TY  - JOUR
A1  - Abdalla, H.
A1  - Abramowski, A.
A1  - Aharonian, Felix A.
A1  - Benkhali, F. Ait
A1  - Akhperjanian, A. G.
A1  - Andersson, T.
A1  - Anguener, E. O.
A1  - Arrieta, M.
A1  - Aubert, P.
A1  - Backes, M.
A1  - Balzer, A.
A1  - Barnard, M.
A1  - Becherini, Y.
A1  - Tjus, J. Becker
A1  - Berge, D.
A1  - Bernhard, S.
A1  - Bernlorhr, K.
A1  - Blackwell, R.
A1  - Bottcher, M.
A1  - Boisson, C.
A1  - Bolmont, J.
A1  - Bordas, Pol
A1  - Bregeon, J.
A1  - Brun, F.
A1  - Brun, P.
A1  - Bryan, M.
A1  - Bulik, T.
A1  - Capasso, M.
A1  - Carr, J.
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chakraborty, N.
A1  - Chalme-Calvet, R.
A1  - Chaves, R. C. G.
A1  - Chen, A.
A1  - Chevalier, J.
A1  - Chretien, M.
A1  - Colafrancesco, S.
A1  - Cologna, G.
A1  - Condon, B.
A1  - Conrad, J.
A1  - Cui, Y.
A1  - Davids, I. D.
A1  - Decock, J.
A1  - Degrange, B.
A1  - Deil, C.
A1  - Devin, J.
A1  - deWilt, P.
A1  - Dirson, L.
A1  - Djannati-Atai, A.
A1  - Domainko, W.
A1  - Donath, A.
A1  - Dubus, G.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Eger, P.
A1  - Ernenwein, J. -P.
A1  - Eschbach, S.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Fernandes, M. V.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Foerster, A.
A1  - Funk, S.
A1  - Fuessling, M.
A1  - Gabici, S.
A1  - Gajdus, M.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Giavitto, G.
A1  - Giebels, B.
A1  - Glicenstein, J. F.
A1  - Gottschall, D.
A1  - Goyal, A.
A1  - Grondin, M. -H.
A1  - Hadasch, D.
A1  - Hahn, J.
A1  - Haupt, M.
A1  - Hawkes, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hervet, O.
A1  - Hinton, J. A.
A1  - Hofmann, W.
A1  - Hoischen, Clemens
A1  - Holler, M.
A1  - Horns, D.
A1  - Ivascenko, A.
A1  - Jacholkowska, A.
A1  - Jamrozy, M.
A1  - Janiak, M.
A1  - Jankowsky, D.
A1  - Jankowsky, F.
A1  - Jingo, M.
A1  - Jogler, T.
A1  - Jouvin, L.
A1  - Jung-Richardt, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katz, U.
A1  - Kerszberg, D.
A1  - Khelifi, B.
A1  - Er, M. Kie Ff
A1  - King, J.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Kolitzus, D.
A1  - Komin, Nu.
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Kraus, M.
A1  - Krayzel, F.
A1  - Kruger, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lau, J.
A1  - Lees, J. -P.
A1  - Lefaucheur, J.
A1  - Lefranc, V.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Leser, E.
A1  - Lohse, T.
A1  - Lorentz, M.
A1  - Liu, R.
A1  - Lopez-Coto, R.
A1  - Lypova, I.
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Mariaud, C.
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - Meintjes, P. J.
A1  - Meyer, M.
A1  - Mitchell, A. M. W.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Mohrmann, L.
A1  - Mora, K.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - de Naurois, M.
A1  - Niederwanger, F.
A1  - Niemiec, J.
A1  - Oakes, L.
A1  - Odaka, H.
A1  - Oettl, S.
A1  - Ohm, S.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, M.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perennes, C.
A1  - Petrucci, P. -O.
A1  - Peyaud, B.
A1  - Piel, Q.
A1  - Pita, S.
A1  - Poon, H.
A1  - Prokhorov, D.
A1  - Prokoph, H.
A1  - Puehlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - de los Reyes, R.
A1  - Rieger, F.
A1  - Romoli, C.
A1  - Rosier-Lees, S.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Salek, D.
A1  - Sanchez, D. A.
A1  - Santangelo, Andrea
A1  - Sasaki, M.
A1  - Schlickeiser, R.
A1  - Schussler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwemmer, S.
A1  - Settimo, M.
A1  - Seyffert, A. S.
A1  - Shafi, N.
A1  - Shilon, I.
A1  - Simoni, R.
A1  - Sol, H.
A1  - Spanier, F.
A1  - Spengler, G.
A1  - Spies, F.
A1  - Ert, Ff
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian Michael
A1  - Stinzing, F.
A1  - Stycz, K.
A1  - Sushch, I.
A1  - Tavernet, J. -P.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tibaldo, L.
A1  - Tiziani, D.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Tuffs, R.
A1  - Uchiyama, Y.
A1  - van der Walt, D. J.
A1  - van Eldik, C.
A1  - van Rensburg, C.
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Veh, J.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Vink, J.
A1  - Voisin, F.
A1  - Voelk, H. J.
A1  - Vuillaume, T.
A1  - Wadiasingh, Z.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Wagner, R. M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Yang, R.
A1  - Zabalza, V.
A1  - Zaborov, D.
A1  - Zacharias, M.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zefi, F.
A1  - Ziegler, A.
A1  - Zywucka, N.
T1  - Characterizing the gamma-ray long-term variability of PKS2155 304 with HESS and Fermi-LAT
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Studying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155 304 is analyzed in the high (HE, 100MeV < E < 300 GeV) and very high energy (VHE, E > 200 GeV) gamma-ray domain. Over the course of similar to 9 yr of H. E. S. S. observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index beta(VHE) = 1 .10(+ 0 : 10) (0 : 13)) on timescales larger than one day. An analysis of similar to 5.5 yr of HE Fermi-LAT data gives consistent results (beta(HE) = 1 : 20(+ 0 : 21) (0 : 23), on timescales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior (beta similar to 2) seen on shorter timescales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection.
KW  - galaxies: active
KW  - BL Lacertae objects: individual: PKS 2155-304
KW  - gamma rays: galaxies
KW  - galaxies: jets
KW  - galaxies: nuclei
KW  - radiation mechanisms: non-thermal
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201629419
SN  - 1432-0746
SN  - 0004-6361
VL  - 598
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Abdalla, Hassan E.
A1  - Abramowski, Attila
A1  - Aharonian, Felix A.
A1  - Benkhali, Faical  Ait
A1  - Akhperjanian, A. G.
A1  - Andersson, T.
A1  - Anguner, Ekrem Oǧuzhan
A1  - Arakawa, M.
A1  - Arrieta, M.
A1  - Aubert, Pierre
A1  - Backes, Michael
A1  - Balzer, Arnim
A1  - Barnard, Michelle
A1  - Becherini, Yvonne
A1  - Tjus, J. Becker
A1  - Berge, David
A1  - Bernhard, Sabrina
A1  - Bernlöhr, K.
A1  - Blackwell, R.
A1  - Böttcher, Markus
A1  - Boisson, Catherine
A1  - Bolmont, J.
A1  - Bonnefoy, S.
A1  - Bordas, Pol
A1  - Bregeon, Johan
A1  - Brun, Francois
A1  - Brun, Pierre
A1  - Bryan, Mark
A1  - Buechele, M.
A1  - Bulik, Tomasz
A1  - Capasso, M.
A1  - Carr, John
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chakraborty, N.
A1  - Chaves, Ryan C. G.
A1  - Chen, Andrew
A1  - Chevalier, J.
A1  - Coffaro, M.
A1  - Colafrancesco, Sergio
A1  - Cologna, Gabriele
A1  - Condon, B.
A1  - Conrad, Jan
A1  - Cui, Y.
A1  - Davids, I. D.
A1  - Decock, J.
A1  - Degrange, B.
A1  - Deil, C.
A1  - Devin, J.
A1  - de Wilt, P.
A1  - Dirson, L.
A1  - Djannati-Atai, A.
A1  - Domainko, W.
A1  - Donath, A.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Eger, P.
A1  - Ernenwein, J. -P.
A1  - Eschbach, S.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Fernandes, M. V.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Foerster, A.
A1  - Funk, S.
A1  - Fuessling, M.
A1  - Gabici, S.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Giavitto, G.
A1  - Giebels, B.
A1  - Glicenstein, J. F.
A1  - Gottschall, D.
A1  - Goyal, A.
A1  - Grondin, M. -H.
A1  - Hahn, J.
A1  - Haupt, M.
A1  - Hawkes, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hinton, James Anthony
A1  - Hofmann, W.
A1  - Hoischen, Clemens
A1  - Holch, Tim Lukas
A1  - Holler, M.
A1  - Horns, D.
A1  - Ivascenko, A.
A1  - Iwasaki, H.
A1  - Jacholkowska, A.
A1  - Jamrozy, M.
A1  - Janiak, M.
A1  - Jankowsky, D.
A1  - Jankowsky, F.
A1  - Jingo, M.
A1  - Jogler, T.
A1  - Jouvin, L.
A1  - Jung-Richardt, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katsuragawa, M.
A1  - Katz, U.
A1  - Kerszberg, D.
A1  - Khangulyan, D.
A1  - Khelifi, B.
A1  - King, J.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Kolitzus, D.
A1  - Komin, Nu.
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Kraus, M.
A1  - Kruger, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lau, J.
A1  - Lees, J. -P.
A1  - Lefaucheur, J.
A1  - Lefranc, V.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Leser, Eva
A1  - Lohse, T.
A1  - Lorentz, M.
A1  - Liu, R.
A1  - Lopez-Coto, R.
A1  - Lypova, I.
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Mariaud, C.
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - Meintjes, P. J.
A1  - Meyer, M.
A1  - Mitchell, A. M. W.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Mohrmann, L.
A1  - Mora, K.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - Nakashima, S.
A1  - de Naurois, M.
A1  - Niederwanger, F.
A1  - Niemiec, J.
A1  - Oakes, L.
A1  - Odaka, H.
A1  - Ohm, S.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, M.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perennes, C.
A1  - Petrucci, P. -O.
A1  - Peyaud, B.
A1  - Piel, Q.
A1  - Pita, S.
A1  - Poon, H.
A1  - Prokhorov, D.
A1  - Prokoph, H.
A1  - Puehlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Rauth, R.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - de los Reyes, R.
A1  - Richter, S.
A1  - Rieger, F.
A1  - Romoli, C.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Saito, S.
A1  - Salek, D.
A1  - Sanchez, David M.
A1  - Santangelo, Andrea
A1  - Sasaki, M.
A1  - Schlickeiser, R.
A1  - Schussler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwemmer, S.
A1  - Seglar-Arroyo, M.
A1  - Settimo, M.
A1  - Seyffert, A. S.
A1  - Shafi, N.
A1  - Shilon, I.
A1  - Simoni, R.
A1  - Sol, H.
A1  - Spanier, F.
A1  - Spengler, G.
A1  - Spies, F.
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian
A1  - Stycz, K.
A1  - Sushch, Iurii
A1  - Takahashi, T.
A1  - Tavernet, J. -P.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tibaldo, L.
A1  - Tiziani, D.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Tsuji, N.
A1  - Tuffs, R.
A1  - Uchiyama, Y.
A1  - van der Walt, D. J.
A1  - van Eldik, C.
A1  - van Rensburg, C.
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Veh, J.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Vink, J.
A1  - Voisin, F.
A1  - Voelk, H. J.
A1  - Vuillaume, T.
A1  - Wadiasingh, Z.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Wagner, R. M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Yang, R.
A1  - Zaborov, D.
A1  - Zacharias, M.
A1  - Zanin, R.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zefi, F.
A1  - Ziegler, A.
A1  - Zywucka, N.
T1  - Measurement of the EBL spectral energy distribution using the VHE gamma-ray spectra of HESS blazars
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Very high-energy gamma rays (VHE, E greater than or similar to 100 GeV) propagating over cosmological distances can interact with the low-energy photons of the extragalactic background light (EBL) and produce electron-positron pairs. The transparency of the Universe to VHE gamma rays is then directly related to the spectral energy distribution (SED) of the EBL. The observation of features in the VHE energy spectra of extragalactic sources allows the EBL to be measured, which otherwise is very difficult. An EBL model-independent measurement of the EBL SED with the H.E.S.S. array of Cherenkov telescopes is presented. It was obtained by extracting the EBL absorption signal from the reanalysis of high-quality spectra of blazars. From H.E.S.S. data alone the EBL signature is detected at a significance of 9.5 sigma, and the intensity of the EBL obtained in different spectral bands is presented together with the associated gamma-ray horizon.
KW  - gamma rays: galaxies
KW  - BL Lacertae objects: general
KW  - cosmic background radiation
KW  - infrared: diffuse background
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201731200
SN  - 1432-0746
VL  - 606
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Abdalla, Hassan E.
A1  - Abramowski, Attila
A1  - Aharonian, Felix A.
A1  - Benkhali, Faical  Ait
A1  - Anguner, Ekrem Oǧuzhan
A1  - Arakawa, M.
A1  - Arrieta, M.
A1  - Aubert, Pierre
A1  - Backes, Michael
A1  - Balzer, Arnim
A1  - Barnard, Michelle
A1  - Becherini, Yvonne
A1  - Tjus, J. Becker
A1  - Berge, David
A1  - Bernhard, Sabrina
A1  - Bernlöhr, K.
A1  - Blackwell, R.
A1  - Böttcher, Markus
A1  - Boisson, Catherine
A1  - Bolmont, J.
A1  - Bonnefoy, S.
A1  - Bordas, Pol
A1  - Bregeon, Johan
A1  - Brun, Francois
A1  - Brun, Pierre
A1  - Bryan, Mark
A1  - Buechele, M.
A1  - Bulik, Tomasz
A1  - Capasso, M.
A1  - Caroff, S.
A1  - Carosi, A.
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chakraborty, N.
A1  - Chaves, Ryan C. G.
A1  - Chen, Andrew
A1  - Chevalier, J.
A1  - Colafrancesco, Sergio
A1  - Condon, B.
A1  - Conrad, Jan
A1  - Davids, I. D.
A1  - Decock, J.
A1  - Deil, C.
A1  - Devin, J.
A1  - deWilt, P.
A1  - Dirson, L.
A1  - Djannati-Atai, A.
A1  - Donath, A.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Emery, G.
A1  - Ernenwein, J. -P.
A1  - Eschbach, S.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Fernandes, M. V.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Funk, S.
A1  - Fuessling, M.
A1  - Gabici, S.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Gate, F.
A1  - Giavitto, G.
A1  - Giebels, B.
A1  - Glawion, D.
A1  - Glicenstein, J. F.
A1  - Gottschall, D.
A1  - Grondin, M. -H.
A1  - Hahn, J.
A1  - Haupt, M.
A1  - Hawkes, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hinton, James Anthony
A1  - Hofmann, W.
A1  - Hoischen, Clemens
A1  - Holch, Tim Lukas
A1  - Holler, M.
A1  - Horns, D.
A1  - Ivascenko, A.
A1  - Iwasaki, H.
A1  - Jacholkowska, A.
A1  - Jamrozy, M.
A1  - Jankowsky, D.
A1  - Jankowsky, F.
A1  - Jingo, M.
A1  - Jouvin, L.
A1  - Jung-Richardt, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katsuragawa, M.
A1  - Katz, U.
A1  - Kerszberg, D.
A1  - Khangulyan, D.
A1  - Khelifi, B.
A1  - King, J.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Komin, Nu.
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Kraus, M.
A1  - Kruer, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lau, J.
A1  - Lees, J. -P.
A1  - Lefaucheur, J.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Leser, Eva
A1  - Lohse, T.
A1  - Lorentz, M.
A1  - Liu, R.
A1  - Lopez-Coto, R.
A1  - Lypova, I.
A1  - Malyshev, D.
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Mariaud, C.
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - Meintjes, P. J.
A1  - Meyer, M.
A1  - Mitchell, A. M. W.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Mohrmann, L.
A1  - Mora, K.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - Nakashima, S.
A1  - de Naurois, M.
A1  - Ndiyavala, H.
A1  - Niederwanger, F.
A1  - Niemiec, J.
A1  - Oakes, L.
A1  - Odaka, H.
A1  - Ohm, S.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, M.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perennes, C.
A1  - Petrucci, P. -O.
A1  - Peyaud, B.
A1  - Piel, Q.
A1  - Pita, S.
A1  - Poireau, V.
A1  - Poon, H.
A1  - Prokhorov, D.
A1  - Prokoph, H.
A1  - Puehlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Rauth, R.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - de los Reyes, R.
A1  - Rieger, F.
A1  - Rinchiuso, L.
A1  - Romoli, C.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Saito, S.
A1  - Sanchez, David M.
A1  - Santangelo, Andrea
A1  - Sasaki, M.
A1  - Schlickeiser, R.
A1  - Schussler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwemmer, S.
A1  - Seglar-Arroyo, M.
A1  - Settimo, M.
A1  - Seyffert, A. S.
A1  - Shafi, N.
A1  - Shilon, I.
A1  - Shiningayamwe, K.
A1  - Simoni, R.
A1  - Sol, H.
A1  - Spanier, F.
A1  - Spir-Jacob, M.
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian
A1  - Steppa, Constantin Beverly
A1  - Sushch, Iurii
A1  - Takahashi, T.
A1  - Tavernet, J. -P.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tibaldo, L.
A1  - Tiziani, D.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Tsirou, M.
A1  - Tsuji, N.
A1  - Tuffs, R.
A1  - Uchiyama, Y.
A1  - van der Walt, D. J.
A1  - van Eldik, C.
A1  - van Rensburg, C.
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Veh, J.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Vink, J.
A1  - Voisin, F.
A1  - Voelk, H. J.
A1  - Vuillaume, T.
A1  - Wadiasingh, Z.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Wagner, R. M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Yang, R.
A1  - Zaborov, D.
A1  - Zacharias, M.
A1  - Zanin, R.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zefi, F.
A1  - Ziegler, A.
A1  - Zorn, J.
A1  - Zywucka, N.
T1  - TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with HESS
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
N2  - We search for high-energy gamma-ray emission from the binary neutron star merger GW170817 with the H.E.S.S. Imaging Air Cherenkov Telescopes. The observations presented here have been obtained starting only 5.3 hr after GW170817. The H.E.S.S. target selection identified regions of high probability to find a counterpart of the gravitational-wave event. The first of these regions contained the counterpart SSS17a that has been identified in the optical range several hours after our observations. We can therefore present the first data obtained by a ground-based pointing instrument on this object. A subsequent monitoring campaign with the H.E.S.S. telescopes extended over several days, covering timescales from 0.22 to 5.2 days and energy ranges between 270 GeV to 8.55 TeV. No significant gamma-ray emission has been found. The derived upper limits on the very-high-energy gamma-ray flux for the first time constrain non-thermal, high-energy emission following the merger of a confirmed binary neutron star system.
KW  - gamma-ray burst: individual (GRB 170817A)
KW  - gamma rays: general
KW  - gravitational waves
Y1  - 2017
U6  - https://doi.org/10.3847/2041-8213/aa97d2
SN  - 2041-8205
SN  - 2041-8213
VL  - 850
SP  - 628
EP  - 650
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Abeysekara, A. U.
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Cerruti, M.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Huetten, M.
A1  - Hanna, D.
A1  - Hervet, O.
A1  - Holder, J.
A1  - Humensky, T. B.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Maier, G.
A1  - McArthur, S.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Petrashyk, A.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Sadeh, I.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tyler, J.
A1  - Vassiliev, V. V.
A1  - Wakely, S. P.
A1  - Weiner, O. M.
A1  - Weinstein, A.
A1  - Wilcox, P.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zitzer, B.
T1  - Discovery of Very-high-energy Emission from RGB J2243+203 and Derivation of Its Redshift Upper Limit
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series
N2  - Very-high-energy (VHE; > 100 GeV) gamma-ray emission from the blazar RGB J2243+203 was discovered with the VERITAS Cherenkov telescope array, during the period between 2014 December 21 and 24. The VERITAS energy spectrum from this source can be fitted by a power law with a photon index of 4.6 +/- 0.5, and a flux normalization at 0.15 TeV of (6.3 +/- 1.1) x 10(-10) cm(-2) s(-1) TeV-1. The integrated Fermi-LAT flux from 1 to 100 GeV during the VERITAS detection is (4.1 +/- 0.8) x 10(-8) cm(-2) s(-1), which is an order of magnitude larger than the four-year-averaged flux in the same energy range reported in the 3FGL catalog, (4.0 +/- 0.1 x 10(-9) cm(-2) s(-1)). The detection with VERITAS triggered observations in the X-ray band with the Swift-XRT. However, due to scheduling constraints Swift-XRT observations were performed 67 hr after the VERITAS detection, rather than simultaneously with the VERITAS observations. The observed X-ray energy spectrum between 2 and 10 keV can be fitted with a power law with a spectral index of 2.7 +/- 0.2, and the integrated photon flux in the same energy band is (3.6 +/- 0.6) x 10(-13) cm(-2) s(-1). EBL-model-dependent upper limits of the blazar redshift have been derived. Depending on the EBL model used, the upper limit varies in the range from z < 0.9 to z < 1.1.
KW  - galaxies: individual (RGB J2243+203)
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4365/aa8d76
SN  - 0067-0049
SN  - 1538-4365
VL  - 233
SP  - 1188
EP  - 1204
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Abeysekara, A. U.
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, Wystan
A1  - Bird, Ralph
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cerruti, M.
A1  - Chen, X.
A1  - Ciupik, L.
A1  - Cui, W.
A1  - Dickinson, H. J.
A1  - Eisch, J. D.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Hutten, M.
A1  - Hakansson, N.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Humensky, T. B.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Maier, G.
A1  - McArthur, S.
A1  - McCann, A.
A1  - Meagher, K.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nguyen, T.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Pelassa, V.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weiner, O. M.
A1  - Weinstein, A.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Fegan, S.
A1  - Giebels, B.
A1  - Horan, D.
A1  - Berdyugin, A.
A1  - Kuan, J.
A1  - Lindfors, E.
A1  - Nilsson, K.
A1  - Oksanen, A.
A1  - Prokoph, H.
A1  - Reinthal, R.
A1  - Takalo, L.
A1  - Zefi, F.
T1  - A Luminous and Isolated Gamma-Ray Flare from the Blazar B2 1215+30
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - B2 1215+30 is a BL-Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes and subsequently confirmed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2. 1215+30 during routine monitoring observations of the blazar 1ES. 1218+304, located in the same field of view. The TeV flux reached 2.4 times the Crab Nebula flux with a variability timescale of <3.6 hr. Multiwavelength observations with Fermi-LAT, Swift, and the Tuorla Observatory revealed a correlated high GeV flux state and no significant optical counterpart to the flare, with a spectral energy distribution where the gamma-ray luminosity exceeds the synchrotron luminosity. When interpreted in the framework of a onezone leptonic model, the observed emission implies a high degree of beaming, with Doppler factor delta > 10, and an electron population with spectral index p < 2.3.
KW  - BL Lacertae objects: individual (B2 1215+30, VER J1217+301)
KW  - galaxies: active
KW  - galaxies: jets
KW  - galaxies: nuclei
KW  - gamma rays: galaxies
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/836/2/205
SN  - 0004-637X
SN  - 1538-4357
VL  - 836
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Acero, F.
A1  - Aloisio, R.
A1  - Amans, J.
A1  - Amato, Elena
A1  - Antonelli, L. A.
A1  - Aramo, C.
A1  - Armstrong, T.
A1  - Arqueros, F.
A1  - Asano, Katsuaki
A1  - Ashley, M.
A1  - Backes, M.
A1  - Balazs, C.
A1  - Balzer, A.
A1  - Bamba, Aya
A1  - Barkov, Maxim
A1  - Barrio, J. A.
A1  - Benbow, Wystan
A1  - Bernloehr, K.
A1  - Beshley, V.
A1  - Bigongiari, C.
A1  - Biland, A.
A1  - Bilinsky, A.
A1  - Bissaldi, Elisabetta
A1  - Biteau, J.
A1  - Blanch, O.
A1  - Blasi, P.
A1  - Blazek, J.
A1  - Boisson, C.
A1  - Bonanno, G.
A1  - Bonardi, A.
A1  - Bonavolonta, C.
A1  - Bonnoli, G.
A1  - Braiding, C.
A1  - Brau-Nogue, S.
A1  - Bregeon, J.
A1  - Brown, A. M.
A1  - Bugaev, V.
A1  - Bulgarelli, A.
A1  - Bulik, T.
A1  - Burton, Michael
A1  - Burtovoi, A.
A1  - Busetto, G.
A1  - Bottcher, M.
A1  - Cameron, R.
A1  - Capalbi, M.
A1  - Caproni, Anderson
A1  - Caraveo, P.
A1  - Carosi, R.
A1  - Cascone, E.
A1  - Cerruti, M.
A1  - Chaty, Sylvain
A1  - Chen, A.
A1  - Chen, X.
A1  - Chernyakova, M.
A1  - Chikawa, M.
A1  - Chudoba, J.
A1  - Cohen-Tanugi, J.
A1  - Colafrancesco, S.
A1  - Conforti, V.
A1  - Contreras, J. L.
A1  - Costa, A.
A1  - Cotter, G.
A1  - Covino, Stefano
A1  - Covone, G.
A1  - Cumani, P.
A1  - Cusumano, G.
A1  - Daniel, M.
A1  - Dazzi, F.
A1  - De Angelis, A.
A1  - De Cesare, G.
A1  - De Franco, A.
A1  - De Frondat, F.
A1  - Dal Pino, E. M. de Gouveia
A1  - De Lisio, C.
A1  - Lopez, R. de los Reyes
A1  - De Lotto, B.
A1  - de Naurois, M.
A1  - De Palma, F.
A1  - Del Santo, M.
A1  - Delgado, C.
A1  - della Volpe, D.
A1  - Di Girolamo, T.
A1  - Di Giulio, C.
A1  - Di Pierro, F.
A1  - Di Venere, L.
A1  - Doro, M.
A1  - Dournaux, J.
A1  - Dumas, D.
A1  - Dwarkadas, Vikram V.
A1  - Diaz, C.
A1  - Ebr, J.
A1  - Egberts, Kathrin
A1  - Einecke, S.
A1  - Elsaesser, D.
A1  - Eschbach, S.
A1  - Falceta-Goncalves, D.
A1  - Fasola, G.
A1  - Fedorova, E.
A1  - Fernandez-Barral, A.
A1  - Ferrand, Gilles
A1  - Fesquet, M.
A1  - Fiandrini, E.
A1  - Fiasson, A.
A1  - Filipovic, Miroslav D.
A1  - Fioretti, V.
A1  - Font, L.
A1  - Fontaine, Gilles
A1  - Franco, F. J.
A1  - Freixas Coromina, L.
A1  - Fujita, Yutaka
A1  - Fukui, Y.
A1  - Funk, S.
A1  - Forster, A.
A1  - Gadola, A.
A1  - Lopez, R. Garcia
A1  - Garczarczyk, M.
A1  - Giglietto, N.
A1  - Giordano, F.
A1  - Giuliani, A.
A1  - Glicenstein, J.
A1  - Gnatyk, R.
A1  - Goldoni, P.
A1  - Grabarczyk, T.
A1  - Graciani, R.
A1  - Graham, J.
A1  - Grandi, P.
A1  - Granot, Jonathan
A1  - Green, A. J.
A1  - Griffiths, S.
A1  - Gunji, S.
A1  - Hakobyan, H.
A1  - Hara, S.
A1  - Hassan, T.
A1  - Hayashida, M.
A1  - Heller, M.
A1  - Helo, J. C.
A1  - Hinton, J.
A1  - Hnatyk, B.
A1  - Huet, J.
A1  - Huetten, M.
A1  - Humensky, T. B.
A1  - Hussein, M.
A1  - Horandel, J.
A1  - Ikeno, Y.
A1  - Inada, T.
A1  - Inome, Y.
A1  - Inoue, S.
A1  - Inoue, T.
A1  - Inoue, Y.
A1  - Ioka, K.
A1  - Iori, Maurizio
A1  - Jacquemier, J.
A1  - Janecek, P.
A1  - Jankowsky, D.
A1  - Jung, I.
A1  - Kaaret, P.
A1  - Katagiri, H.
A1  - Kimeswenger, S.
A1  - Kimura, Shigeo S.
A1  - Knodlseder, J.
A1  - Koch, B.
A1  - Kocot, J.
A1  - Kohri, K.
A1  - Komin, N.
A1  - Konno, Y.
A1  - Kosack, K.
A1  - Koyama, S.
A1  - Kraus, Michaela
A1  - Kubo, Hidetoshi
A1  - Mezek, G. Kukec
A1  - Kushida, J.
A1  - La Palombara, N.
A1  - Lalik, K.
A1  - Lamanna, G.
A1  - Landt, H.
A1  - Lapington, J.
A1  - Laporte, P.
A1  - Lee, S.
A1  - Lees, J.
A1  - Lefaucheur, J.
A1  - Lenain, J. -P.
A1  - Leto, Giuseppe
A1  - Lindfors, E.
A1  - Lohse, T.
A1  - Lombardi, S.
A1  - Longo, F.
A1  - Lopez, M.
A1  - Lucarelli, F.
A1  - Luque-Escamilla, Pedro Luis
A1  - Lopez-Coto, R.
A1  - Maccarone, M. C.
A1  - Maier, G.
A1  - Malaguti, G.
A1  - Mandat, D.
A1  - Maneva, G.
A1  - Mangano, S.
A1  - Marcowith, Alexandre
A1  - Marti, J.
A1  - Martinez, M.
A1  - Martinez, G.
A1  - Masuda, S.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Melioli, Claudio
A1  - Mineo, T.
A1  - Mirabal, N.
A1  - Mizuno, T.
A1  - Moderski, R.
A1  - Mohammed, M.
A1  - Montaruli, T.
A1  - Moralejo, A.
A1  - Mori, K.
A1  - Morlino, G.
A1  - Morselli, A.
A1  - Moulin, Emmanuel
A1  - Mukherjee, R.
A1  - Mundell, C.
A1  - Muraishi, H.
A1  - Murase, Kohta
A1  - Nagataki, Shigehiro
A1  - Nagayoshi, T.
A1  - Naito, T.
A1  - Nakajima, D.
A1  - Nakamori, T.
A1  - Nemmen, R.
A1  - Niemiec, Jacek
A1  - Nieto, D.
A1  - Nievas-Rosillo, M.
A1  - Nikolajuk, M.
A1  - Nishijima, K.
A1  - Noda, K.
A1  - Nogues, L.
A1  - Nosek, D.
A1  - Novosyadlyj, B.
A1  - Nozaki, S.
A1  - Ohira, Yutaka
A1  - Ohishi, M.
A1  - Ohm, S.
A1  - Okumura, A.
A1  - Ong, R. A.
A1  - Orito, R.
A1  - Orlati, A.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Padovani, Marco
A1  - Palacio, J.
A1  - Palatka, M.
A1  - Paredes, Josep M.
A1  - Pavy, S.
A1  - Persic, M.
A1  - Petrucci, P.
A1  - Petruk, Oleh
A1  - Pisarski, A.
A1  - Pohl, Martin
A1  - Porcelli, A.
A1  - Prandini, E.
A1  - Prast, J.
A1  - Principe, G.
A1  - Prouza, M.
A1  - Pueschel, Elisa
A1  - Puelhofer, G.
A1  - Quirrenbach, A.
A1  - Rameez, M.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - Ribo, M.
A1  - Rico, J.
A1  - Rizi, V.
A1  - Rodriguez, J.
A1  - Fernandez, G. Rodriguez
A1  - Rodriguez Vazquez, J. J.
A1  - Romano, Patrizia
A1  - Romeo, G.
A1  - Rosado, J.
A1  - Rousselle, J.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Sadeh, I.
A1  - Safi-Harb, S.
A1  - Saito, T.
A1  - Sakaki, N.
A1  - Sanchez, D.
A1  - Sangiorgi, P.
A1  - Sano, H.
A1  - Santander, M.
A1  - Sarkar, S.
A1  - Sawada, M.
A1  - Schioppa, E. J.
A1  - Schoorlemmer, H.
A1  - Schovanek, P.
A1  - Schussler, F.
A1  - Sergijenko, O.
A1  - Servillat, M.
A1  - Shalchi, A.
A1  - Shellard, R. C.
A1  - Siejkowski, H.
A1  - Sillanpaa, A.
A1  - Simone, D.
A1  - Sliusar, V.
A1  - Sol, H.
A1  - Stanic, S.
A1  - Starling, R.
A1  - Stawarz, L.
A1  - Stefanik, S.
A1  - Stephan, M.
A1  - Stolarczyk, T.
A1  - Szanecki, M.
A1  - Szepieniec, T.
A1  - Tagliaferri, G.
A1  - Tajima, H.
A1  - Takahashi, M.
A1  - Takeda, J.
A1  - Tanaka, M.
A1  - Tanaka, S.
A1  - Tejedor, L. A.
A1  - Telezhinsky, Igor O.
A1  - Temnikov, P.
A1  - Terada, Y.
A1  - Tescaro, D.
A1  - Teshima, M.
A1  - Testa, V.
A1  - Thoudam, S.
A1  - Tokanai, F.
A1  - Torres, D. F.
A1  - Torresi, E.
A1  - Tosti, G.
A1  - Townsley, C.
A1  - Travnicek, P.
A1  - Trichard, C.
A1  - Trifoglio, M.
A1  - Tsujimoto, S.
A1  - Vagelli, V.
A1  - Vallania, P.
A1  - Valore, L.
A1  - van Driel, W.
A1  - van Eldik, C.
A1  - Vandenbroucke, Justin
A1  - Vassiliev, V.
A1  - Vecchi, M.
A1  - Vercellone, Stefano
A1  - Vergani, S.
A1  - Vigorito, C.
A1  - Vorobiov, S.
A1  - Vrastil, M.
A1  - Vazquez Acosta, M. L.
A1  - Wagner, S. J.
A1  - Wagner, R.
A1  - Wakely, S. P.
A1  - Walter, R.
A1  - Ward, J. E.
A1  - Watson, J. J.
A1  - Weinstein, A.
A1  - White, M.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Wischnewski, R.
A1  - Wojcik, P.
A1  - Yamamoto, T.
A1  - Yamamoto, H.
A1  - Yamazaki, Ryo
A1  - Yanagita, S.
A1  - Yang, L.
A1  - Yoshida, T.
A1  - Yoshida, M.
A1  - Yoshiike, S.
A1  - Yoshikoshi, T.
A1  - Zacharias, M.
A1  - Zampieri, L.
A1  - Zanin, R.
A1  - Zavrtanik, M.
A1  - Zavrtanik, D.
A1  - Zdziarski, A.
A1  - Zech, Alraune
A1  - Zechlin, Hannes
A1  - Zhdanov, V.
A1  - Ziegler, A.
A1  - Zorn, J.
T1  - Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
KW  - cosmic rays
KW  - gamma rays: ISM
KW  - ISM: individual objects (RX J1713.7-3946, G347.3-0.5)
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa6d67
SN  - 0004-637X
SN  - 1538-4357
VL  - 840
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Ahnen, M. L.
A1  - Ansoldi, S.
A1  - Antonelli, L. A.
A1  - Antoranz, P.
A1  - Babic, A.
A1  - Banerjee, B.
A1  - Bangale, P.
A1  - de Almeida, U. Barres
A1  - Barrio, J. A.
A1  - Gonzalez, J. Becerra
A1  - Bednarek, W.
A1  - Bernardini, E.
A1  - Berti, A.
A1  - Biasuzzi, B.
A1  - Biland, A.
A1  - Blanch, O.
A1  - Bonnefoy, S.
A1  - Bonnoli, G.
A1  - Borracci, F.
A1  - Bretz, T.
A1  - Buson, S.
A1  - Carosi, A.
A1  - Chatterjee, A.
A1  - Clavero, R.
A1  - Colin, P.
A1  - Colombo, E.
A1  - Contreras, J. L.
A1  - Cortina, J.
A1  - Covino, S.
A1  - Da Vela, P.
A1  - Dazzi, F.
A1  - De Angelis, A.
A1  - De Lotto, B.
A1  - Wilhelmi, E. de Ona
A1  - Di Pierro, F.
A1  - Doert, M.
A1  - Dominguez, A.
A1  - Prester, D. Dominis
A1  - Dorner, D.
A1  - Doro, M.
A1  - Einecke, S.
A1  - Glawion, D. Eisenacher
A1  - Elsaesser, D.
A1  - Engelkemeier, M.
A1  - Ramazani, V. Fallah
A1  - Fernandez-Barral, A.
A1  - Fidalgo, D.
A1  - Fonseca, M. V.
A1  - Font, L.
A1  - Frantzen, K.
A1  - Fruck, C.
A1  - Galindo, D.
A1  - Lopez, R. J. Garcia
A1  - Garczarczyk, M.
A1  - Terrats, D. Garrido
A1  - Gaug, M.
A1  - Giammaria, P.
A1  - Godinovic, N.
A1  - Gonzalez Munoz, A.
A1  - Gora, D.
A1  - Guberman, D.
A1  - Hadasch, D.
A1  - Hahn, A.
A1  - Hanabata, Y.
A1  - Hayashida, M.
A1  - Herrera, J.
A1  - Hose, J.
A1  - Hrupec, D.
A1  - Hughes, G.
A1  - Idec, W.
A1  - Kodani, K.
A1  - Konno, Y.
A1  - Kubo, H.
A1  - Kushida, J.
A1  - La Barbera, A.
A1  - Lelas, D.
A1  - Lindfors, E.
A1  - Lombardi, S.
A1  - Longo, F.
A1  - Lopez, M.
A1  - Lopez-Coto, R.
A1  - Majumdar, P.
A1  - Makariev, M.
A1  - Mallot, K.
A1  - Maneva, G.
A1  - Manganaro, M.
A1  - Mannheim, K.
A1  - Maraschi, L.
A1  - Marcote, B.
A1  - Mariotti, M.
A1  - Martinez, M.
A1  - Mazin, D.
A1  - Menzel, U.
A1  - Miranda, J. M.
A1  - Mirzoyan, R.
A1  - Moralejo, A.
A1  - Moretti, E.
A1  - Nakajima, D.
A1  - Neustroev, V.
A1  - Niedzwiecki, A.
A1  - Rosillo, M. Nievas
A1  - Nilsson, K.
A1  - Nishijima, K.
A1  - Noda, K.
A1  - Nogues, L.
A1  - Overkemping, A.
A1  - Paiano, S.
A1  - Palacio, J.
A1  - Palatiello, M.
A1  - Paneque, D.
A1  - Paoletti, R.
A1  - Paredes, J. M.
A1  - Paredes-Fortuny, X.
A1  - Pedaletti, G.
A1  - Peresano, M.
A1  - Perri, L.
A1  - Persic, M.
A1  - Poutanen, J.
A1  - Moroni, P. G. Prada
A1  - Prandini, E.
A1  - Puljak, I.
A1  - Reichardt, I.
A1  - Rhode, W.
A1  - Ribo, M.
A1  - Rico, J.
A1  - Rodriguez Garcia, J.
A1  - Saito, T.
A1  - Satalecka, K.
A1  - Schroder, S.
A1  - Schultz, C.
A1  - Schweizer, T.
A1  - Shore, S. N.
A1  - Sillanpaa, A.
A1  - Sitarek, J.
A1  - Snidaric, I.
A1  - Sobczynska, D.
A1  - Stamerra, A.
A1  - Steinbring, T.
A1  - Strzys, M.
A1  - Suric, T.
A1  - Takalo, L.
A1  - Tavecchio, F.
A1  - Temnikov, P.
A1  - Terzic, T.
A1  - Tescaro, D.
A1  - Teshima, M.
A1  - Thaele, J.
A1  - Torres, D. F.
A1  - Toyama, T.
A1  - Treves, A.
A1  - Vanzo, G.
A1  - Verguilov, V.
A1  - Vovk, I.
A1  - Ward, J. E.
A1  - Will, M.
A1  - Wu, M. H.
A1  - Zanin, R.
A1  - Abeysekara, A. U.
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Dickinson, H. J.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Flinders, A.
A1  - Fortson, L.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Huetten, M.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Humensky, T. B.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Krennrich, F.
A1  - Lang, M. J.
A1  - Maier, G.
A1  - McCann, A.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, N.
A1  - Park, N.
A1  - Perkins, J.
A1  - Pichel, A.
A1  - Pohl, M.
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rovero, A. C.
A1  - Rulten, C.
A1  - Sadeh, I.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Wilcox, P.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zitzer, B.
A1  - Razzaque, S.
A1  - Villata, M.
A1  - Raiteri, C. M.
A1  - Aller, H. D.
A1  - Aller, M. F.
A1  - Larionov, V. M.
A1  - Arkharov, A. A.
A1  - Blinov, D. A.
A1  - Efimova, N. V.
A1  - Grishina, T. S.
A1  - Hagen-Thorn, V. A.
A1  - Kopatskaya, E. N.
A1  - Larionova, L. V.
A1  - Larionova, E. G.
A1  - Morozova, D. A.
A1  - Troitsky, I. S.
A1  - Ligustri, R.
A1  - Calcidese, P.
A1  - Berdyugin, A.
A1  - Kurtanidze, O. M.
A1  - Nikolashvili, M. G.
A1  - Kimeridze, G. N.
A1  - Sigua, L. A.
A1  - Kurtanidze, S. O.
A1  - Chigladze, R. A.
A1  - Chen, W. P.
A1  - Koptelova, E.
A1  - Sakamoto, T.
A1  - Sadun, A. C.
A1  - Moody, J. W.
A1  - Pace, C.
A1  - Pearson, R.
A1  - Yatsu, Y.
A1  - Mori, Y.
A1  - Carraminyana, A.
A1  - Carrasco, L.
A1  - de la Fuente, E.
A1  - Norris, J. P.
A1  - Smith, P. S.
A1  - Wehrle, A.
A1  - Gurwell, M. A.
A1  - Zook, A.
A1  - Pagani, C.
A1  - Perri, M.
A1  - Capalbi, M.
A1  - Cesarini, A.
A1  - Krimm, H. A.
A1  - Kovalev, Y. Y.
A1  - Kovalev, Yu. A.
A1  - Ros, E.
A1  - Pushkarev, A. B.
A1  - Lister, M. L.
A1  - Sokolovsky, K. V.
A1  - Kadler, M.
A1  - Piner, G.
A1  - Lahteenmaki, A.
A1  - Tornikoski, M.
A1  - Angelakis, E.
A1  - Krichbaum, T. P.
A1  - Nestoras, I.
A1  - Fuhrmann, L.
A1  - Zensus, J. A.
A1  - Cassaro, P.
A1  - Orlati, A.
A1  - Maccaferri, G.
A1  - Leto, P.
A1  - Giroletti, M.
A1  - Richards, J. L.
A1  - Max-Moerbeck, W.
A1  - Readhead, A. C. S.
T1  - Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims. We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the gamma-ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV to hard X-rays; and GASP-WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the gamma-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Methods. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the "single-curve SSC model adjustment" typically reported in the literature. Results. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X-rays and very-high-energy (> 100 GeV, VHE) gamma-rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA), cannot be satisfactorily reproduced by either a one-zone or a two-independent-zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub-hour timescales (detected at VHE gamma rays). Conclusions. The higher variability in the VHE emission and lack of correlation with the X-ray emission indicate that, at least during the 4.5-month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE gamma rays do not make a dominant contribution to the similar to 1 keV emission. Alternatively, there could be a very variable component contributing to the VHE gamma-ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid-scan show that there is some degeneracy in both the one-zone and the two-zone SSC scenarios probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The observed gamma-ray flaring activity, with the EVPA rotation coincident with the first gamma-ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties.
KW  - BL Lacertae objects: individual: Markarian 501
KW  - methods: data analysis
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201629540
SN  - 1432-0746
VL  - 603
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Allen, C.
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Bourbeau, E.
A1  - Brose, Robert
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Chen, Xuhui
A1  - Christiansen, J. L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Daniel, M. K.
A1  - Eisch, J. D.
A1  - Falcone, Abe
A1  - Feng, Q.
A1  - Fernandez-Alonso, M.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Flinders, A.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Huetten, M.
A1  - Hakansson, N.
A1  - Hanna, D.
A1  - Hervet, O.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Maier, G.
A1  - McArthur, S.
A1  - McCann, A.
A1  - Meagher, K.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nguyen, T.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Petrashyk, A.
A1  - Pichel, A.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rovero, A. C.
A1  - Rulten, C.
A1  - Sadeh, I.
A1  - Santander, Marcos
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
T1  - Very-High-Energy gamma-Ray Observations of the Blazar 1ES 2344+514 with VERITAS
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present very-high-energy gamma-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8 sigma in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3 sigma level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (x(2)/NDF = 7.89/6) by a power-law function with an index Gamma = 2.46 +/- 0.06(stat) +/- 0.20(sys) and extends to at least 8 TeV. The extragalactic-backgroundlight-deabsorbed spectrum is adequately fit (x(2)/NDF = 6.73/6) by a power-law function with an index Gamma = 2.15 +/- 0.06(stat) +/- 0.20(sys) while an F-test indicates that the power law with an exponential cut-off function provides a marginally better fit (x(2)/NDF = 2.56/5) at the 2.1 sigma level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.
KW  - astroparticle physics
KW  - BL Lacertae objects: individual: 1ES 2344+514=VERJ2347+517
KW  - gamma-rays: galaxies
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx1756
SN  - 0035-8711
SN  - 1365-2966
VL  - 471
SP  - 2117
EP  - 2123
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Almeida, Leonardo A.
A1  - Sana, H.
A1  - Taylor, W.
A1  - Barbá, Rodolfo
A1  - Bonanos, Alceste Z.
A1  - Crowther, Paul
A1  - Damineli, Augusto
A1  - de Koter, A.
A1  - de Mink, Selma E.
A1  - Evans, C. J.
A1  - Gieles, Mark
A1  - Grin, Nathan J.
A1  - Hénault-Brunet, V.
A1  - Langer, Norbert
A1  - Lennon, D.
A1  - Lockwood, Sean
A1  - Maíz Apellániz, Jesús
A1  - Moffat, A. F. J.
A1  - Neijssel, C.
A1  - Norman, C.
A1  - Ramírez-Agudelo, O. H.
A1  - Richardson, N. D.
A1  - Schootemeijer, Abel
A1  - Shenar, Tomer
A1  - Soszyński, Igor
A1  - Tramper, Frank
A1  - Vink, J. S.
T1  - The tarantula massive binary monitoring
BT  - I. Observational campaign and OB-type spectroscopic binaries
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context:
Massive binaries play a crucial role in the Universe. Knowing the distributions of their orbital parameters is important for a wide range of topics from stellar feedback to binary evolution channels and from the distribution of supernova types to gravitational wave progenitors, yet no direct measurements exist outside the Milky Way.
Aims:
The Tarantula Massive Binary Monitoring project was designed to help fill this gap by obtaining multi-epoch radial velocity (RV) monitoring of 102 massive binaries in the 30 Doradus region.
Methods: 
In this paper we analyze 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined (SB1) and 31 double-lined (SB2) spectroscopic binaries.
Results: 
Overall, the binary fraction and orbital properties across the 30 Doradus region are found to be similar to existing Galactic samples. This indicates that within these domains environmental effects are of second order in shaping the properties of massive binary systems. A small difference is found in the distribution of orbital periods, which is slightly flatter (in log space) in 30 Doradus than in the Galaxy, although this may be compatible within error estimates and differences in the fitting methodology. Also, orbital periods in 30 Doradus can be as short as 1.1 d, somewhat shorter than seen in Galactic samples. Equal mass binaries (q> 0.95) in 30 Doradus are all found outside NGC 2070, the central association that surrounds R136a, the very young and massive cluster at 30 Doradus’s core. Most of the differences, albeit small, are compatible with expectations from binary evolution. One outstanding exception, however, is the fact that earlier spectral types (O2–O7) tend to have shorter orbital periods than later spectral types (O9.2–O9.7).
Conclusions: 
Our results point to a relative universality of the incidence rate of massive binaries and their orbital properties in the metallicity range from solar (Z⊙) to about half solar. This provides the first direct constraints on massive binary properties in massive star-forming galaxies at the Universe’s peak of star formation at redshifts z ~ 1 to 2 which are estimated to have Z ~ 0.5 Z⊙.
KW  - stars: early-type
KW  - stars: massive
KW  - binaries: spectroscopic
KW  - binaries: close
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201629844
SN  - 1432-0746
VL  - 598
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - THES
A1  - Anders, Friedrich
T1  - Disentangling the chemodynamical history of the Milky Way disc with asteroseismology and spectroscopy
T1  - Die chemodynamische Entwicklung der Milchstraßenscheibe im Lichte asteroseismischer und spektroskopischer Himmelsdurchmusterungen
N2  - Galaxies are among the most complex systems that can currently be modelled with a computer. A realistic simulation must take into account cosmology and gravitation as well as effects of plasma, nuclear, and particle physics that occur on very different time, length, and energy scales. The Milky Way is the ideal test bench for such simulations, because we can observe millions of its individual stars whose kinematics and chemical composition are records of the evolution of our Galaxy. Thanks to the advent of multi-object spectroscopic surveys, we can systematically study stellar populations in a much larger volume of the Milky Way. While the wealth of new data will certainly revolutionise our picture of the formation and evolution of our Galaxy and galaxies in general, the big-data era of Galactic astronomy also confronts us with new observational, theoretical, and computational challenges.

This thesis aims at finding new observational constraints to test Milky-Way models, primarily based on infra-red spectroscopy from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and asteroseismic data from the CoRoT mission. We compare our findings with chemical-evolution models and more sophisticated chemodynamical simulations. In particular we use the new powerful technique of combining asteroseismic and spectroscopic observations that allows us to test the time dimension of such models for the first time. With CoRoT and APOGEE (CoRoGEE) we can infer much more precise ages for distant field red-giant stars, opening up a new window for Galactic archaeology. 
Another important aspect of this work is the forward-simulation approach that we pursued when interpreting these complex datasets and comparing them to chemodynamical models. 

The first part of the thesis contains the first chemodynamical study conducted with the APOGEE survey. Our sample comprises more than 20,000 red-giant stars located within 6 kpc from the Sun, and thus greatly enlarges the Galactic volume covered with high-resolution spectroscopic observations. Because APOGEE is much less affected by interstellar dust extinction, the sample covers the disc regions very close to the Galactic plane that are typically avoided by optical surveys. This allows us to investigate the chemo-kinematic properties of the Milky Way's thin disc outside the solar vicinity. We measure, for the first time with high-resolution data, the radial metallicity gradient of the disc as a function of distance from the Galactic plane, demonstrating that the gradient flattens and even changes its sign for mid-plane distances greater than 1 kpc.
Furthermore, we detect a gap between the high- and low-[$\alpha$/Fe] sequences in the chemical-abundance diagram (associated with the thin and thick disc) that unlike in previous surveys can hardly be explained by selection effects. Using 6D kinematic information, we also present chemical-abundance diagrams cleaned from stars on kinematically hot orbits. The data allow us to confirm without doubt that the scale length of the (chemically-defined) thick disc is significantly shorter than that of the thin disc.

In the second part, we present our results of the first combination of asteroseismic and spectroscopic data in the context of Galactic Archaeology. We analyse APOGEE follow-up observations of 606 solar-like oscillating red giants in two CoRoT fields close to the Galactic plane. These stars cover a large radial range of the Galactic disc (4.5 kpc $\lesssim R_{\rm Gal}\lesssim15$ kpc) and a large age baseline (0.5 Gyr $\lesssim \tau\lesssim$ 13 Gyr), allowing us to study the age- and radius-dependence of the [$\alpha$/Fe] vs. [Fe/H] distributions. We find that the age distribution of the high-[$\alpha$/Fe] sequence appears to be broader than expected from a monolithically-formed old thick disc that stopped to form stars 10 Gyr ago. In particular, we discover a significant population of apparently young, [$\alpha$/Fe]-rich stars in the CoRoGEE data whose existence cannot be explained by standard chemical-evolution models. These peculiar stars are much more abundant in the inner CoRoT field LRc01 than in the outer-disc field LRc01, suggesting that at least part of this population has a chemical-evolution rather than a stellar-evolution origin, possibly due to a peculiar chemical-enrichment history of the inner disc. We also find that strong radial migration is needed to explain the abundance of super-metal-rich stars in the outer disc. 

Finally, we use the CoRoGEE sample to study the time evolution of the radial metallicity gradient in the thin disc, an observable that has been the subject of observational and theoretical debate for more than 20 years. By dividing the CoRoGEE dataset into six age bins, performing a careful statistical analysis of the radial [Fe/H], [O/H], and [Mg/Fe] distributions, and accounting for the biases introduced by the observation strategy, we obtain reliable gradient measurements. The slope of the radial [Fe/H] gradient of the young red-giant population ($-0.058\pm0.008$ [stat.] $\pm0.003$ [syst.] dex/kpc) is consistent with recent Cepheid data. For the age range of $1-4$ Gyr, the gradient steepens slightly ($-0.066\pm0.007\pm0.002$ dex/kpc), before flattening again to reach a value of  $\sim-0.03$ dex/kpc for stars with ages between 6 and 10 Gyr. This age dependence of the [Fe/H] gradient can be explained by a nearly constant negative [Fe/H] gradient of $\sim-0.07$ dex/kpc in the interstellar medium over the past 10 Gyr, together with stellar heating and migration. Radial migration also offers a new explanation for the puzzling observation that intermediate-age open clusters in the solar vicinity (unlike field stars) tend to have higher metallicities than their younger counterparts. We suggest that non-migrating clusters are more likely to be kinematically disrupted, which creates a bias towards high-metallicity migrators from the inner disc and may even steepen the intermediate-age cluster abundance gradient.
N2  - Galaxien gehören zu den komplexesten physikalischen Systemen, die derzeit mit Computern modelliert werden können. Eine realistische Galaxiensimulation muss kosmologische Effekte genauso berücksichtigen wie die Gesetze der Plasma-, Kern-, und Teilchenphysik. Die Milchstraße ist ein ideales Labor für die Überprüfung solcher Simulationen, da moderne Teleskope die Kinematik und chemische Zusammensetzung von Millionen von Milchstraßensternen einzeln analysieren können und uns so einen Einblick in die Entstehungsgeschichte unserer Galaxie geben. Dank groß angelegter spektroskopischer Himmelsdurchmusterungen lassen sich seit Neuestem auch stellare Populationen in fernen Regionen der Milchstraße systematisch studieren. Dieser Datenreichtum hat das Potential, unseren Blick auf die Entstehung unserer kosmischen Heimat zu revolutionieren, konfrontiert die Forschung aber auch mit neuen beobachtungstechnischen, theoretischen und numerischen Herausforderungen.

Das Ziel dieser Arbeit ist es, moderne numerische Modelle der Milchstraße mittels neuer Beobachtungen zu testen. Hierbei benutzen wir vor Allem Infrarotspektroskopiedaten des Apache Point Observatory Galactic Evolution Experiment (APOGEE), sowie asteroseismische Daten der europäischen Exoplanetenmission CoRoT. Wir vergleichen unsere Resultate mit semianalytischen chemischen Entwicklungsmodellen und komplexeren chemodynamischen Simulationen, wobei uns die Kombination von asteroseismischen und spektroskopischen Daten erlaubt, zum ersten Mal die Zeitdimension solcher Modelle zu testen. Mit den CoRoT-APOGEE-Beobachtungen (kurz: CoRoGEE) lassen sich viel präzisere Altersbestimmungen für entfernte Riesensterne berechnen. Ein weiterer wichtiger Bestandteil dieser Arbeit ist die Verwendung sogenannter Mock-Beobachtungen, bei denen ein chemodynamisches Milchstraßenmodell so ``beobachtet'' wird wie die Milchstraße selbst, unter möglichst realistischer Berücksichtigung aller Beobachtungseffekte. Dies erlaubt uns akkuratere Vergleiche von Modellen und Daten, und ermöglicht eine einfachere Interpretation.

Der erste Teil dieser Arbeit enthält eine chemodynamische Untersuchung von mehr als 20,000 roten Riesensternen, die sich bis zu 6 kpc (20,000 Lichtjahre) entfernt befinden. Diese Studie, die mit den ersten APOGEE-Daten gemacht wurde, konnte so das galaktische Volumen, das mit hochauflösender Spektroskopie je beobachtet wurde, dramatisch vergrößern. Weil die Sensitivität von APOGEE als Infrarotexperiment weit weniger durch interstellare Extinktion behindert wird, dringt unsere Stichprobe außerdem in die Regionen nahe der galaktischen Ebene vor, die typischerweise von optischen Durchmusterungen vermieden werden. Das erlaubt es uns, die chemodynamischen Eigenschaften der dünnen Milchstraßenscheibe außerhalb der unmittelbaren Sonnenumgebung zu studieren. Wir können beispielsweise zum ersten Mal mit hochauflösender Spektroskopie den radialen Metallizitätsgradienten der Scheibe als Funktion des Abstands von der Scheibenebene messen und zeigen, dass dieser Gradient oberhalb von 1 kpc positiv ist. Außerdem detektieren wir eine Lücke zwischen den Populationen I und II im chemischen [$\alpha$/Fe]-[Fe/H]-Häufigkeitsdiagramm, die im Gegensatz zur früheren Datenerhebungen schwerlich durch Selektionseffekte erklärt werden kann. Da für viele Sterne zudem 6-dimensionale Phasenrauminformationen vorliegen, können wir außerdem chemische Häufigkeitsdiagramme analysieren, in denen stellare Passanten aus anderen galaktischen Regionen ausgeblendet werden. Unsere Daten bestätigen zweifelsfrei die kurze Skalenlänge der dicken Milchstraßenscheibe (Population II).  

Im zweiten Teil der Arbeit nutzen wir zum ersten Mal kombinierte seismisch-spektroskopische Beobachtungen zum Zwecke der Galaktischen Archäologie. Wir analysieren dabei APOGEE-Beobachtungen von 606 roten Riesensternen in zwei CoRoT-Himmelsfeldern nahe der Galaktischen Ebene. Die Sterne sind über einen weiten Bereich der Galaktischen Scheibe verteilt (4.5 kpc $\lesssim R_{\rm Gal}\lesssim15$ kpc) und decken eine große Altersspanne ab (0.5 Gyr $\lesssim \tau\lesssim$ 13 Gyr), was es uns erlaubt, sowohl die Alters- als auch die radiale Abhängigkeit der [$\alpha$/Fe]-[Fe/H]-Verteilungen zu untersuchen. Dabei konstatieren wir, dass die Altersverteilung der Population-II-Sterne breiter ist als man es für ein monolithisches Kollaps-Szenario der dicken Scheibe erwarten würde. Vor Allem liegt das an einer vorher nicht bekannten, aber signifikanten Population scheinbar junger [$\alpha$/Fe]-reicher Sterne, deren Existenz mit Standardmodellen für die chemische Evolution der Galaktischen Scheibe nicht erklärbar ist. Diese eigentümlichen Objekte sind viel häufiger in der inneren Scheibe zu finden als in der äußeren, was darauf hindeutet, dass zumindest ein Teil dieser Population tatsächlich einen physikalischen Ursprung hat (etwa eine besondere chemische Entwicklung nahe des Galaktischen Balkens) und nicht etwa auf systematische Fehler in der Altersbestimmung zurückzuführen ist. Ein weiteres Resultat ergibt sich aus der Fülle von super-metallreichen Sternen in der äußeren Scheibe: der Effekt radialer Sternmigration scheint dort eine größere Rolle zu spielen als bisher angenommen.

Im letzten Teil nutzen wir die CoRoGEE-Stichprobe, um die Zeitentwicklung des radialen Metallizitätsgradienten der dünnen Scheibe zu studieren; eine Unbekannte, die sowohl unter Theoretikern als auch unter Beobachtern in den letzten zwanzig Jahren immer wieder für Diskussionen sorgte. Wir teilen dazu die CoRoGEE-Daten in sechs Altersgruppen ein und  erhalten durch eine sorgfältige statistische Analyse der radialen [Fe/H] Verteilungen unter Berücksichtigung systematischer Unsicherheiten verlässliche Werte für den Metallizitätsgradienten. Dessen Anstieg für die junge Population der roten Riesen  ($-0.058\pm0.008$ [stat.] $\pm0.003$ [syst.] dex/kpc) ist konsistent mit den neuesten Messungen an Cepheiden. Im Altersbereich $1-4$ Gyr verzeichnen wir einen leicht steileren Gradienten ($-0.066\pm0.007\pm0.002$ dex/kpc), der für ältere Sterne (6--10 Gyr) wieder flacher ausfällt ($\sim-0.03$ dex/kpc). Diese Altersabhängigkeit des Metallizitätsgradienten lässt sich unter anderem durch ein Modell erklären, in dem der Metallizitätsgradient des interstellaren Medium etwa konstant bei $~-0.07$ dex/kpc liegt und in alten stellaren Populationen durch kinematische Effekte wie stellare Migration verwaschen wird. Stellare radiale Migration eröffnet uns außerdem eine elegante Erklärung für die verwundernde Tatsche, dass Sternhaufen mittleren Alters in der Sonnenumgebung oft höhere Metallizitäten aufweisen als junge Haufen. Um das zu erklären, schlagen wir ein Szenario vor, in dem nichtmigrierende Haufen eher durch gravitative Wechselwirkungen in der Scheibe zersöort werden als migrierende, was in der Sonnenumgebung eine Verzerrung zu Gunsten metallreicherer Haufen aus der inneren Scheibe nach sich zöge und, wie ebenfalls beobachtet, zur Folge hätte, dass der Metallizitätsgradient der mittelalten Haufenpopulation viel steiler wäre als der der jungen Haufen.
KW  - galactic astronomy
KW  - Milky Way evolution
KW  - Milky Way chemodynamics
KW  - red giant stars
KW  - asteroseismology
KW  - spectroscopy
KW  - galaktische Astrophysik
KW  - Entstehung der Milchstraße
KW  - Chemodynamik der Milchstraße
KW  - rote Riesensterne
KW  - Asteroseismologie
KW  - Spektroskopie
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-396681
ER  - 
TY  - GEN
A1  - Angüner, Ekrem Oǧuzhan
A1  - Aharonian, Felix A.
A1  - Bordas, Pol
A1  - Casanova, Sabrina
A1  - Hoischen, Clemens
A1  - Oya, I.
A1  - Ziegler, A.
T1  - HESS J1826-130
BT  - a very hard gamma-Ray spectrum source in the Galactic Plane
T2  - AIP conference proceedings / American Institute of Physics
N2  - HESS J1826-130 is an unidentified hard spectrum source discovered by H.E.S.S. along the Galactic plane, the spectral index being Gamma = 1.6 with an exponential cut-off at about 12 TeV. While the source does not have a clear counterpart at longer wavelengths, the very hard spectrum emission at TeV energies implies that electrons or protons accelerated up to several hundreds of TeV are responsible for the emission. In the hadronic case, the VHE emission can be produced by runaway cosmic-rays colliding with the dense molecular clouds spatially coincident with the H.E.S.S. source.
Y1  - 2017
SN  - 978-0-7354-1456-3
U6  - https://doi.org/10.1063/1.4968928
SN  - 0094-243X
SN  - 1551-7616
VL  - 1792
IS  - 1
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Anielski, Alexander
A1  - Barbosa Pfannes, Eva Katharina
A1  - Beta, Carsten
T1  - Adaptive microfluidic gradient generator for quantitative chemotaxis experiments
JF  - Review of scientific instruments : a monthly journal devoted to scientific instruments, apparatus, and techniques
N2  - Chemotactic motion in a chemical gradient is an essential cellular function that controls many processes in the living world. For a better understanding and more detailed modelling of the underlying mechanisms of chemotaxis, quantitative investigations in controlled environments are needed. We developed a setup that allows us to separately address the dependencies of the chemotactic motion on the average background concentration and on the gradient steepness of the chemoattractant. In particular, both the background concentration and the gradient steepness can be kept constant at the position of the cell while it moves along in the gradient direction. This is achieved by generating a well-defined chemoattractant gradient using flow photolysis. In this approach, the chemoattractant is released by a light-induced reaction from a caged precursor in a microfluidic flow chamber upstream of the cell. The flow photolysis approach is combined with an automated real-time cell tracker that determines changes in the cell position and triggers movement of the microscope stage such that the cell motion is compensated and the cell remains at the same position in the gradient profile. The gradient profile can be either determined experimentally using a caged fluorescent dye or may be alternatively determined by numerical solutions of the corresponding physical model. To demonstrate the function of this adaptive microfluidic gradient generator, we compare the chemotactic motion of Dictyostelium discoideum cells in a static gradient and in a gradient that adapts to the position of the moving cell. Published by AIP Publishing.
Y1  - 2017
U6  - https://doi.org/10.1063/1.4978535
SN  - 0034-6748
SN  - 1089-7623
VL  - 88
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Bourbeau, E.
A1  - Brantseg, T.
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cerruti, M.
A1  - Christiansen, J. L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Daniel, M. K.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Geringer-Sameth, A.
A1  - Griffin, S.
A1  - Grube, J.
A1  - Hütten, M.
A1  - Hakansson, N.
A1  - Hanna, D.
A1  - Hervet, O.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Hummensky, B.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Koushiappas, S.
A1  - Krause, M.
A1  - Krennrich, F.
A1  - Lang, M. J.
A1  - Lin, T. T. Y.
A1  - McArthur, S.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Pohl, M.
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Sadeh, I.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Smith, A. W.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Trepanier, S.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Zitzer, B.
T1  - Dark matter constraints from a joint analysis of dwarf Spheroidal galaxy observations with VERITAS
JF  - Physical review : D, Particles, fields, gravitation, and cosmology
N2  - We present constraints on the annihilation cross section of weakly interacting massive particles dark matter based on the joint statistical analysis of four dwarf galaxies with VERITAS. These results are derived from an optimized photon weighting statistical technique that improves on standard imaging atmospheric Cherenkov telescope (IACT) analyses by utilizing the spectral and spatial properties of individual photon events. We report on the results of similar to 230 hours of observations of five dwarf galaxies and the joint statistical analysis of four of the dwarf galaxies. We find no evidence of gamma-ray emission from any individual dwarf nor in the joint analysis. The derived upper limit on the dark matter annihilation cross section from the joint analysis is 1.35 x 10(-23) cm(3) s(-1) at 1 TeV for the bottom quark (b (b) over bar) final state, 2.85 x 10(-24) cm(3) s(-1) at 1 TeV for the tau lepton (tau+tau(-)) final state and 1.32 x 10-25 cm(3) s(-1) at 1 TeV for the gauge boson (gamma gamma) final state.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevD.95.082001
SN  - 2470-0010
SN  - 2470-0029
VL  - 95
IS  - 8
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, Ralph
A1  - Bourbeau, E.
A1  - Bouvier, A.
A1  - Buchovecky, M.
A1  - Bugaev, V.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Ciupik, L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Daniel, M. K.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Hanna, D.
A1  - Hervet, O.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Hutten, M.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Lang, M. J.
A1  - Lin, T. T. Y.
A1  - Maier, G.
A1  - McArthur, S.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rulten, C.
A1  - Sadeh, I.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Trepanier, S.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Wilcox, P.
A1  - Williams, D. A.
A1  - Zitzer, B.
T1  - Gamma-ray observations under bright moonlight with VERITAS
JF  - Astroparticle physics
N2  - Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have been carried out with the VERITAS IACTs under bright moonlight (defined as about three times the night-sky-background (NSB) of a dark extragalactic field, typically occurring when Moon illumination > 35%) in two observing modes, firstly by reducing the voltage applied to the PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to the cameras. This has allowed observations at up to about 30 times previous NSB levels (around 80% Moon illumination), resulting in 30% more observing time between the two modes over the course of a year. These additional observations have already allowed for the detection of a flare from the 1ES 1727 + 502 and for an observing program targeting a measurement of the cosmic-ray positron fraction. We provide details of these new observing modes and their performance relative to the standard VERITAS observations. (C) 2017 Elsevier B.V. All rights reserved.
KW  - Instrumentation
KW  - Moonlight
KW  - Observing methods
KW  - VERITAS
KW  - IACT
Y1  - 2017
U6  - https://doi.org/10.1016/j.astropartphys.2017.03.001
SN  - 0927-6505
SN  - 1873-2852
VL  - 91
SP  - 34
EP  - 43
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, W.
A1  - Buchovecky, M.
A1  - Bugaev, V.
A1  - Cerruti, M.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Falcone, A.
A1  - Alonso, M. Fernandez
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Griffin, S.
A1  - Hutten, M.
A1  - Hervet, O.
A1  - Holder, J.
A1  - Humensky, T. B.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Krennrich, F.
A1  - Lang, M. J.
A1  - Lin, T. T. Y.
A1  - Maier, G.
A1  - McArthur, S.
A1  - Moriarty, P.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Pohl, M.
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rovero, A. C.
A1  - Sadeh, I.
A1  - Shahinyan, K.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Weisgarber, T.
A1  - Wilcox, P.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zitzer, B.
T1  - Search for Magnetically Broadened Cascade Emission from Blazars with VERITAS
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We present a search for magnetically broadened gamma-ray emission around active galactic nuclei (AGNs), using VERITAS observations of seven hard-spectrum blazars. A cascade process occurs when multi-TeV gamma-rays from an AGN interact with extragalactic background light (EBL) photons to produce electron-positron pairs, which then interact with cosmic microwave background photons via inverse-Compton scattering to produce gamma-rays. Due to the deflection of the electron- positron pairs, a non-zero intergalactic magnetic field (IGMF) would potentially produce detectable effects on the angular distribution of the cascade emission. In particular, an angular broadening compared to the unscattered emission could occur. Through non-detection of angularly broadened emission from 1ES 1218 vertical bar 304, the source with the largest predicted cascade fraction, we exclude a range of IGMF strengths around 10(-14) G at the 95% confidence level. The extent of the exclusion range varies with the assumptions made about the intrinsic spectrum of 1ES. 1218+304 and the EBL model used in the simulation of the cascade process. All of the sources are used to set limits on the flux due to extended emission.
KW  - BL Lacertae objects: general
KW  - galaxies: active
KW  - gamma rays: galaxies
KW  - magnetic fields
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/835/2/288
SN  - 0004-637X
SN  - 1538-4357
VL  - 835
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Archer, A.
A1  - Benbow, Wystan
A1  - Bird, Ralph
A1  - Bourbeau, E.
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Cerruti, M.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Dwarkadas, Vikram V.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Griffin, S.
A1  - Huetten, M.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kelley-Hoskins, N.
A1  - Kertzman, M.
A1  - Kieda, D.
A1  - Krause, M.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Maier, G.
A1  - McArthur, S.
A1  - McCann, A.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, Nahee
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Sadeh, I.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Slane, P.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Trepanier, S.
A1  - Tyler, J.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Weisgarber, T.
A1  - Wilcox, P.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zitzer, B.
T1  - Gamma-ray Observations of Tycho's Supernova Remnant with VERITAS and Fermi
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
KW  - material
KW  - data behind figure
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/836/1/23
SN  - 0004-637X
SN  - 1538-4357
VL  - 836
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Arora, Ashima
A1  - Mawass, Mohamad-Assaad
A1  - Sandig, Oliver
A1  - Luo, Chen
A1  - Uenal, Ahmet A.
A1  - Radu, Florin
A1  - Valencia, Sergio
A1  - Kronast, Florian
T1  - Spatially resolved investigation of all optical magnetization switching in TbFe alloys
JF  - Scientific reports
N2  - Optical control of magnetization using femtosecond laser without applying any external magnetic field offers the advantage of switching magnetic states at ultrashort time scales. Recently, all-optical helicity-dependent switching (AO-HDS) has drawn a significant attention for potential information and data storage device applications. In this work, we employ element and magnetization sensitive photoemission electron microscopy (PEEM) to investigate the role of heating in AO-HDS for thin films of the rare-earth transition-metal alloy TbFe. Spatially resolved measurements in a 3–5&#8201;&#956;m sized stationary laser spot demonstrate that AO-HDS is a local phenomenon in the vicinity of thermal demagnetization in a ‘ring’ shaped region. The efficiency of AO-HDS further depends on a local temperature profile around the demagnetized region and thermally activated domain wall motion. We also demonstrate that the thickness of the film determines the preferential switching direction for a particular helicity.
Y1  - 2017
U6  - https://doi.org/10.1038/s41598-017-09615-1
SN  - 2045-2322
VL  - 7
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Aseev, Nikita
A1  - Shprits, Yuri Y.
A1  - Drozdov, Alexander
A1  - Kellerman, Adam C.
A1  - Usanova, Maria E.
A1  - Wang, D.
A1  - Zhelavskaya, Irina
T1  - Signatures of Ultrarelativistic Electron Loss in the Heart of the Outer Radiation Belt Measured by Van Allen Probes
JF  - Journal of geophysical research : Space physics
N2  - Up until recently, signatures of the ultrarelativistic electron loss driven by electromagnetic ion cyclotron (EMIC) waves in the Earth's outer radiation belt have been limited to direct or indirect measurements of electron precipitation or the narrowing of normalized pitch angle distributions in the heart of the belt. In this study, we demonstrate additional observational evidence of ultrarelativistic electron loss that can be driven by resonant interaction with EMIC waves. We analyzed the profiles derived from Van Allen Probe particle data as a function of time and three adiabatic invariants between 9 October and 29 November 2012. New local minimums in the profiles are accompanied by the narrowing of normalized pitch angle distributions and ground&#8208;based detection of EMIC waves. Such a correlation may be indicative of ultrarelativistic electron precipitation into the Earth's atmosphere caused by resonance with EMIC waves.
Y1  - 2017
U6  - https://doi.org/10.1002/2017JA024485
SN  - 2169-9380
SN  - 2169-9402
VL  - 122
SP  - 10102
EP  - 10111
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - THES
A1  - Bekeraitė, Simona
T1  - Distribution functions of rotating galaxies
T1  - Verteilungsfunktionen rotierender Galaxien
BT  - an Integral Field Spectroscopy perspective
BT  - eine Perspektive der Integrale-Feld-Spektroskopie
N2  - The work done during the PhD studies has been focused on measurements of distribution functions of rotating galaxies using integral field spectroscopy observations. 

Throughout the main body of research presented here we have been using CALIFA (Calar Alto Legacy Integral Field Area) survey stellar velocity fields to obtain robust measurements of circular velocities for rotating galaxies of all morphological types. A crucial part of the work was enabled by well-defined CALIFA sample selection criteria: it enabled reconstructing sample-independent distributions of galaxy properties.

In Chapter 2, we measure the distribution in absolute magnitude - circular velocity space for a well-defined sample of 199 rotating CALIFA galaxies using their stellar kinematics. Our aim in this analysis is to avoid subjective selection criteria and to take volume and large-scale structure factors into account. Using stellar velocity fields instead of gas emission line kinematics allows including rapidly rotating early type galaxies. Our initial sample contains 277 galaxies with available stellar velocity fields and growth curve r-band photometry. After rejecting 51 velocity fields that could not be modelled due to the low number of bins, foreground contamination or significant interaction we perform Markov Chain Monte Carlo (MCMC) modelling of the velocity fields, obtaining the rotation curve and kinematic parameters and their realistic uncertainties. We perform an extinction correction and calculate the circular velocity v_circ accounting for pressure support a given galaxy has. The resulting galaxy distribution on the M_r - v_circ plane is then modelled as a mixture of two distinct populations, allowing robust and reproducible rejection of outliers, a significant fraction of which are slow rotators. The selection effects are understood well enough that the incompleteness of the sample can be corrected and the 199 galaxies can be weighted by volume and large-scale structure factors enabling us to fit a volume-corrected Tully-Fisher relation (TFR). More importantly, we also provide the volume-corrected distribution of galaxies in the M_r - v_circ plane, which can be compared with cosmological simulations. The joint distribution of the luminosity and circular velocity space densities, representative over the range of -20 > M_r > -22 mag, can place more stringent constraints on the galaxy formation and evolution scenarios than linear TFR fit parameters or the luminosity function alone.

In Chapter 3, we measure one of the marginal distributions of the M_r - v_circ distribution: the circular velocity function of rotating galaxies. The velocity function is a fundamental observable statistic of the galaxy population, being of a similar importance as the luminosity function, but much more difficult to measure. We present the first directly measured circular velocity function that is representative between 60 < v_circ < 320 km s^-1 for galaxies of all morphological types at a given rotation velocity. For the low mass galaxy population 60 < v_circ < 170 km s^-1, we use the HIPASS velocity function. For the massive galaxy population 170 < v_circ < 320 km s^-1, we use stellar circular velocities from CALIFA. The CALIFA velocity function includes homogeneous velocity measurements of both late and early-type rotation-supported galaxies. It has the crucial advantage of not missing gas-poor massive ellipticals that HI surveys are blind to. We show that both velocity functions can be combined in a seamless manner, as their ranges of validity overlap. The resulting observed velocity function is compared to velocity functions derived from cosmological simulations of the z = 0 galaxy population. We find that dark matter-only simulations show a strong mismatch with the observed VF. Hydrodynamic Illustris simulations fare better, but still do not fully reproduce observations.

In Chapter 4, we present some other work done during the PhD studies, namely, a method that improves the precision of specific angular measurements by combining simultaneous Markov Chain Monte Carlo modelling of ionised gas 2D velocity fields and HI linewidths. To test the method we use a sample of 25 galaxies from the Sydney-AAO Multi-object Integral field (SAMI) survey that had matching ALFALFA HI linewidths. Such a method allows constraining the rotation curve both in the inner regions of a galaxy and in its outskirts, leading to increased precision of specific angular momentum measurements. It could be used to further constrain the observed relation between galaxy mass, specific angular momentum and morphology (Obreschkow & Glazebrook 2014).

Mathematical and computational methods are presented in the appendices.
N2  - Die Arbeit, die während dises Promotionsstudiums durchgeführt wurde, konzentrierte sich auf die Messungen von Verteilungsfunktionen rotierender Galaxien, unter Verwendung von integralen Feldspektroskopiebeobachtungen.

Im Rahmen der hier vorgestellten Hauptforschung haben wir CALIFA (Calar Alto Legacy Integral Field Area) mit stellaren Geschwindigkeitsfeldern verwendet, um robuste Messungen von Kreisförmigen Geschwindigkeiten für rotierende Galaxien aller Morphologien zu erhalten. Der entscheidende Teil dieser Arbeit wurde durch wohl definierte CALIFA-Probenselektionskriterien ermöglicht: Es ermöglichte die Rekonstruktion von probenunabhängigen Verteilungen von Galaxieneigenschaften.

In Kapitel 2 messen wir die Verteilung in absoluten Magnituden für eine wohldefinierte Stichprobe von 199 rotierenden CALIFA-Galaxien unter Berücksichtigung ihrer stellaren Kinematik. Die Selektionseffekte sind verstanden genug damit die Unvollständigkeit der Probe korrigiert werden kann und uns ermöglichen eine volumenkorrigierte Tully-Fisher-Relation (TFR) anzupassen. Noch wichtiger ist es, dass wir auch die volumenkorrigierte Verteilung von Galaxien in der Mr -vcirc Ebene bereitstellen, die mit kosmologischen Simulationen verglichen werden können.

In Kapitel 3 messen wir die Kreisgeschwindigkeitsfunktion der rotierenden Galaxien. Die Geschwindigkeitsfunktion ist eine fundamentale, beobachtbare Messgröße der Galaxienpopulationen, welche von ähnlicher Bedeutung ist wie die Helligkeitsfunktion, aber viel schwerer zu messen ist. Wir präsentieren die erste direkt gemessene Kreisgeschwindigkeitsfunktion, die bei einer gegebenen Rotationsgeschwindigkeit zwischen 60 < vcirc < 320 km s ^-1 für Galaxien aller morphologischen Typen repräsentativ ist. Für die Galaxienpopulation mit niedrigen Massen verwenden wir die HIPASSGeschwindigkeitsfunktion. Für die massiven Galaxienpopulationen verwenden wir stellare Kreisgeschwindigkeiten von CALIFA.

Die CALIFA-Geschwindigkeitsfunktion umfasst homogene Geschwindigkeitsmessungen sowohl der späten als auch der frühen Rotations-gestützten Galaxien. Wir zeigen, dass beide Geschwindigkeitsfunktionen nahtlos kombiniert werden können, da sich ihre Gültigkeitsbereiche überschneiden. Die resultierende beobachtete Geschwindigkeitsfunktion wird mit Geschwindigkeitsfunktionen verglichen, die von kosmologischen Simulationen bei lokale Galaxien abgeleitet sind. Wir finden, dass dunkle Materie-Simulationen und hydrodynamische Illustris Simulationen reproduzieren immer noch nicht vollständig die Beobachtungen.

In Kapitel 4 stellen wir einige andere Arbeiten vor, die während der Promotion durchgeführt wurden. Mathematische und rechnerische Methoden werden in den Anhängen dargestellt.
KW  - galaxies: kinematics and dynamics
KW  - Galaxien: Kinematik und Dynamik
KW  - galaxies: statistics
KW  - galaxies: evolution
KW  - Galaxien: Statistiken
KW  - Galaxien: Evolution
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-420950
ER  - 
TY  - JOUR
A1  - Benduhn, Johannes
A1  - Tvingstedt, Kristofer
A1  - Piersimoni, Fortunato
A1  - Ullbrich, Sascha
A1  - Fan, Yeli
A1  - Tropiano, Manuel
A1  - McGarry, Kathryn A.
A1  - Zeika, Olaf
A1  - Riede, Moritz K.
A1  - Douglas, Christopher J.
A1  - Barlow, Stephen
A1  - Marder, Seth R.
A1  - Neher, Dieter
A1  - Spoltore, Donato
A1  - Vandewal, Koen
T1  - Intrinsic non-radiative voltage losses in fullerene-based organic solar cells
JF  - Nature Energy
N2  - Organic solar cells demonstrate external quantum efficiencies and fill factors approaching those of conventional photovoltaic technologies. However, as compared with the optical gap of the absorber materials, their open-circuit voltage is much lower, largely due to the presence of significant non-radiative recombination. Here, we study a large data set of published and new material combinations and find that non-radiative voltage losses decrease with increasing charge-transfer-state energies. This observation is explained by considering non-radiative charge-transfer-state decay as electron transfer in the Marcus inverted regime, being facilitated by a common skeletal molecular vibrational mode. Our results suggest an intrinsic link between non-radiative voltage losses and electron-vibration coupling, indicating that these losses are unavoidable. Accordingly, the theoretical upper limit for the power conversion efficiency of single-junction organic solar cells would be reduced to about 25.5% and the optimal optical gap increases to (1.45-1.65) eV, that is, (0.2-0.3) eV higher than for technologies with minimized non-radiative voltage losses.
Y1  - 2017
U6  - https://doi.org/10.1038/nenergy.2017.53
SN  - 2058-7546
VL  - 2
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Beta, Carsten
A1  - Kruse, Karsten
T1  - Intracellular oscillations and waves
JF  - Annual review of condensed matter physics
N2  - Dynamic processes in living cells are highly organized in space and time. Unraveling the underlying molecular mechanisms of spatiotemporal pattern formation remains one of the outstanding challenges at the interface between physics and biology. A fundamental recurrent pattern found in many different cell types is that of self-sustained oscillations. They are involved in a wide range of cellular functions, including second messenger signaling, gene expression, and cytoskeletal dynamics. Here, we review recent developments in the field of cellular oscillations and focus on cases where concepts from physics have been instrumental for understanding the underlying mechanisms. We consider biochemical and genetic oscillators as well as oscillations that arise from chemo-mechanical coupling. Finally, we highlight recent studies of intracellular waves that have increasingly moved into the focus of this research field.
KW  - self-sustained oscillations
KW  - biochemical oscillators
KW  - genetic networks
KW  - chemomechanical coupling
KW  - actin waves
Y1  - 2017
SN  - 978-0-8243-5008-6
U6  - https://doi.org/10.1146/annurev-conmatphys-031016-025210
SN  - 1947-5454
VL  - 8
SP  - 239
EP  - 264
PB  - Annual Reviews
CY  - Palo Alto
ER  - 
TY  - JOUR
A1  - Bohdan, Artem
A1  - Niemiec, Jacek
A1  - Kobzar, Oleh
A1  - Pohl, Martin
T1  - Electron Pre-acceleration at Nonrelativistic High-Mach-number Perpendicular Shocks
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We perform particle-in-cell simulations of perpendicular nonrelativistic collisionless shocks to study electron heating and pre-acceleration for parameters that permit the extrapolation to the conditions at young supernova remnants. Our high-resolution large-scale numerical experiments sample a representative portion of the shock surface and demonstrate that the efficiency of electron injection is strongly modulated with the phase of the shock reformation. For plasmas with low and moderate temperature (plasma beta beta p =5.10(-4) and 0.5 beta p =), we explore the nonlinear shock structure and electron pre-acceleration for various orientations of the large-scale magnetic field with respect to the simulation plane, while keeping it at 90 degrees to the shock normal. Ion reflection off of the shock leads to the formation of magnetic filaments in the shock ramp, resulting from Weibel-type instabilities, and electrostatic Buneman modes in the shock foot. In all of the cases under study, the latter provides first-stage electron energization through the shock-surfing acceleration mechanism. The subsequent energization strongly depends on the field orientation and proceeds through adiabatic or second-order Fermi acceleration processes for configurations with the out-of-plane and in-plane field components, respectively. For strictly out-of-plane field, the fraction of suprathermal electrons is much higher than for other configurations, because only in this case are the Buneman modes fully captured by the 2D simulation grid. Shocks in plasma with moderate bp provide more efficient pre-acceleration. The relevance of our results to the physics of fully 3D systems is discussed.
KW  - acceleration of particles
KW  - instabilities
KW  - ISM: supernova remnants
KW  - methods: numerical
KW  - plasmas
KW  - shock
Y1  - 2017
U6  - https://doi.org/10.3847/1538-4357/aa872a
SN  - 0004-637X
SN  - 1538-4357
VL  - 847
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Bolotov, Maxim I.
A1  - Smirnov, Lev A.
A1  - Osipov, Grigory V.
A1  - Pikovskij, Arkadij
T1  - Breathing chimera in a system of phase oscillators
JF  - JETP Letters
N2  - Chimera states consisting of synchronous and asynchronous domains in a medium of nonlinearly coupled phase oscillators have been considered. Stationary inhomogeneous solutions of the Ott-Antonsen equation for a complex order parameter that correspond to fundamental chimeras have been constructed. The direct numerical simulation has shown that these structures under certain conditions are transformed to oscillatory (breathing) chimera regimes because of the development of instability.
Y1  - 2017
U6  - https://doi.org/10.1134/S0021364017180059
SN  - 0021-3640
SN  - 1090-6487
VL  - 106
SP  - 393
EP  - 399
PB  - Pleiades Publ.
CY  - New York
ER  - 
TY  - JOUR
A1  - Borde, Ron
A1  - Smith, Jordan J.
A1  - Sutherland, Rachel
A1  - Nathan, Nicole
A1  - Lubans, David Revalds
T1  - Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis
JF  - Obesity reviews : an official journal of the International Association for the Study of Obesity
N2  - Objective: The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions. Methods: A systematic search was performed to identify randomized controlled trials targeting adolescents (age: >= 10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored. Results: Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects. Conclusion: Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols.
KW  - Accelerometer
KW  - physical activity
KW  - school
KW  - youth
Y1  - 2017
U6  - https://doi.org/10.1111/obr.12517
SN  - 1467-7881
SN  - 1467-789X
VL  - 18
SP  - 476
EP  - 490
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bouakline, Foudhil
A1  - Lorenz, Ulrich J.
A1  - Melani, Giacomo
A1  - Paramonov, Guennaddi K.
A1  - Saalfrank, Peter
T1  - Isotopic effects in vibrational relaxation dynamics of H on a Si(100) surface
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - In a recent paper [U. Lorenz and P. Saalfrank, Chem. Phys. 482, 69 (2017)], we proposed a robust scheme to set up a system-bath model Hamiltonian, describing the coupling of adsorbate vibrations (system) to surface phonons (bath), from first principles. The method is based on an embedded cluster approach, using orthogonal coordinates for system and bath modes, and an anharmonic phononic expansion of the system-bath interaction up to second order. In this contribution, we use this model Hamiltonian to calculate vibrational relaxation rates of H–Si and D–Si bending modes, coupled to a fully H(D)-covered Si(100)-(2×1) surface, at zero temperature. The D–Si bending mode has an anharmonic frequency lying inside the bath frequency spectrum, whereas the H–Si bending mode frequency is outside the bath Debye band. Therefore, in the present calculations, we only take into account one-phonon system-bath couplings for the D–Si system and both one- and two-phonon interaction terms in the case of H–Si. The computation of vibrational lifetimes is performed with two different approaches, namely, Fermi’s golden rule, and a generalized Bixon-Jortner model built in a restricted vibrational space of the adsorbate-surface zeroth-order Hamiltonian. For D–Si, the Bixon-Jortner Hamiltonian can be solved by exact diagonalization, serving as a benchmark, whereas for H–Si, an iterative scheme based on the recursive residue generation method is applied, with excellent convergence properties. We found that the lifetimes obtained with perturbation theory, albeit having almost the same order of magnitude—a few hundred fs for D–Si and a couple of ps for H–Si—, are strongly dependent on the discretized numerical representation of the bath spectral density. On the other hand, the Bixon-Jortner model is free of such numerical deficiencies, therefore providing better estimates of vibrational relaxation rates, at a very low computational cost. The results obtained with this model clearly show a net exponential decay of the time-dependent survival probability for the H–Si initial vibrational state, allowing an easy extraction of the bending mode “lifetime.” This is in contrast with the D–Si system, whose survival probability exhibits a non-monotonic decay, making it difficult to define such a lifetime. This different behavior of the vibrational decay is rationalized in terms of the power spectrum of the adsorbate-surface system. In the case of D–Si, it consists of several, non-uniformly distributed peaks around the bending mode frequency, whereas the H–Si spectrum exhibits a single Lorentzian lineshape, whose width corresponds to the calculated lifetime. The present work gives some insight into mechanisms of vibration-phonon coupling at surfaces. It also serves as a benchmark for multidimensional system-bath quantum dynamics, for comparison with approximate schemes such as reduced, open-system density matrix theory (where the bath is traced out and a Liouville-von Neumann equation is solved) or approximate wavefunction methods to solve the combined system-bath Schrödinger equation.
Y1  - 2017
U6  - https://doi.org/10.1063/1.4994635
SN  - 0021-9606
SN  - 1089-7690
VL  - 147
IS  - 14
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Bozzo, Enrico
A1  - Bernardini, F.
A1  - Ferrigno, Carlo
A1  - Falanga, M.
A1  - Romano, Patrizia
A1  - Oskinova, Lida
T1  - The accretion environment of supergiant fast X-ray transients probed with XMM-Newton
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. Supergiant fast X-ray (SFXT) transients are a peculiar class of supergiant X-ray binaries characterized by a remarkable variability in the X-ray domain, widely ascribed to accretion from a clumpy stellar wind. Aims. In this paper we performed a systematic and homogeneous analysis of the sufficiently bright X-ray flares observed with XMM-Newton from the supergiant fast X-ray transients to probe spectral variations on timescales as short as a few hundred seconds. Our ultimate goal is to investigate whether SFXT flares and outbursts are triggered by the presence of clumps, and to reveal whether strongly or mildly dense clumps are required. Methods. For all sources, we employ a technique developed by our group already exploited in a number of our previous papers, making use of an adaptive rebinned hardness ratio to optimally select the time intervals for the spectral extraction. A total of twelve observations performed in the direction of five SFXTs are reported, providing the largest sample of events available so far. Results. Using the original results reported here and those obtained with our technique from the analysis of two previously published XMM-Newton observations of IGR J17544-2619 and IGR J18410-0535, we show that both strongly and mildly dense clumps can trigger these events. In the former case, the local absorption column density may increase by a factor of >> 3, while in the latter case, the increase is only a factor of similar to 2-3 (or lower). An increase in the absorption column density is generally recorded during the rise of the flares/outbursts, while a drop follows when the source achieves peak flux. In a few cases, a re-increase of the absorption column density after the flare is also detected, and we discovered one absorption event related to the passage of an unaccreted clump in front of the compact object. Overall, there seems to be no obvious correlation between the dynamic ranges in the X-ray fluxes and absorption column densities in supergiant fast X-ray transients, with an indication that lower densities are recorded at the highest fluxes. Conclusions. The spectral variations measured in all sources are in agreement with the idea that the flares/outbursts are triggered by the presence of dense structures in the wind interacting with the X-rays from the compact object (leading to photoionization). The lack of correlation between the dynamic ranges in the X-ray fluxes and absorption column densities can be explained by the presence of accretion inhibition mechanism(s). Based on the knowledge acquired so far on the SFXTs, we propose a classification of the flares/outbursts from these sources in order to drive future observational investigations. We suggest that the difference between the classes of flares/outbursts is related to the fact that the mechanism(s) inhibiting accretion can be overcome more easily in some sources compared to others. We also investigate the possibility that different stellar wind structures, other than clumps, could provide the means to temporarily overcome the inhibition of accretion in supergiant fast X-ray transients.
KW  - X-rays: individuals: IGRJ18450-0435
KW  - X-rays: individuals: IGRJ17544-2619
KW  - X-rays: binaries
KW  - X-rays: individuals: SAXJ1818.6-1703
KW  - X-rays: individuals: IGRJ17354-3255
KW  - X-rays: individuals: IGRJ16328-4726
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201730398
SN  - 1432-0746
VL  - 608
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Bozzo, Enrico
A1  - Oskinova, Lida
A1  - Lobel, A.
A1  - Hamann, Wolf-Rainer
T1  - The super-orbital modulation of supergiant high-mass X-ray binaries
JF  - Astronomy and astrophysics : an international weekly journal
N2  - The long-term X-ray light curves of classical supergiant X-ray binaries and supergiant fast X-ray transients show relatively similar super-orbital modulations, which are still lacking a sound interpretation. We propose that these modulations are related to the presence of corotating interaction regions (CIRs) known to thread the winds of OB supergiants. To test this hypothesis, we couple the outcomes of three-dimensional (3D) hydrodynamic models for the formation of CIRs in stellar winds with a simplified recipe for the accretion onto a neutron star. The results show that the synthetic X-ray light curves are indeed modulated by the presence of the CIRs. The exact period and amplitude of these modulations depend on a number of parameters governing the hydrodynamic wind models and on the binary orbital configuration. To compare our model predictions with the observations, we apply the 3D wind structure previously shown to well explain the appearance of discrete absorption components in the UV time series of a prototypical B0.5I-type supergiant. Using the orbital parameters of IGRJ 16493-4348, which has the same B0.5I donor spectral type, the period and modulations in the simulated X-ray light curve are similar to the observed ones, thus providing support to our scenario. We propose that the presence of CIRs in donor star winds should be considered in future theoretical and simulation efforts of wind-fed X-ray binaries.
KW  - X-rays: stars
KW  - X-rays: binaries
KW  - gamma rays: stars
KW  - stars: massive
KW  - stars: neutron
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201731930
SN  - 1432-0746
VL  - 606
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Bruno, Giovanni
A1  - Vogel, Sven C.
T1  - Simultaneous determination of high-temperature crystal structure and texture of synthetic porous cordierite
JF  - Journal of applied crystallography
N2  - The evolution of the crystal structure and crystallographic texture of porous synthetic cordierite was studied by in situ high-temperature neutron diffraction up to 1373 K, providing the first in situ high-temperature texture measurement of this technologically important material. It was observed that the crystal texture slightly weakens with increasing temperature, concurrently with subtle changes in the crystal structure. These changes are in agreement with previous work, leading the authors to the conclusion that high-temperature neutron diffraction allows reliable crystallographic characterization of materials with moderate texture. It was also observed that structural changes occur at about the glass transition temperature of the cordierite glass (between 973 and 1073 K). Crystal structure refinements were conducted with and without quantitative texture analysis being part of the Rietveld refinement, and a critical comparison of the results is presented, contributing to the sparse body of literature on combined texture and crystal structure refinements.
KW  - synthetic extruded cordierite
KW  - crystal texture
KW  - high temperature
KW  - atomic distances
KW  - atomic displacement parameters
KW  - neutron diffraction
Y1  - 2017
U6  - https://doi.org/10.1107/S160057671700406X
SN  - 1600-5767
VL  - 50
SP  - 749
EP  - 762
PB  - International Union of Crystallography
CY  - Chester
ER  - 
TY  - JOUR
A1  - Buschhüter, David
A1  - Spoden, Christian
A1  - Borowski, Andreas
T1  - Physics knowledge of first semester physics students in Germany
BT  - a comparison of 1978 and 2013 cohorts
JF  - International journal of science education
N2  - Over the last decades, the percentage of the age group choosing to pursue university studies has increased significantly across the world. At the same time, there are university teachers who believe that the standards have fallen. There is little research on whether students nowadays demonstrate knowledge or abilities similar to that of the preceding cohorts. However, in times of educational expansion, empirical evidence on student test performance is extremely helpful in evaluating how well educational systems cope with the increasing numbers of students. In this study, we compared a sample of 2322 physics freshmen from 2013 with another sample of 2718 physics freshmen from 1978 at universities in Germany with regard to their physics knowledge based on their results in the same entrance test. Previous results on mathematics knowledge and abilities in the same sample of students indicated that there was no severe decline in their average achievement. This paper compares the physics knowledge of the same two samples of students. Contrary to their mathematics results, their physics results showed a substantial decrease in physics knowledge as measured by the test.
KW  - University physics
KW  - entrance test
KW  - generational comparison
Y1  - 2017
U6  - https://doi.org/10.1080/09500693.2017.1318457
SN  - 0950-0693
SN  - 1464-5289
VL  - 39
IS  - 9
SP  - 1109
EP  - 1132
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Cabeza, Sandra
A1  - Mishurova, Tatiana
A1  - Garcés, Gonzales
A1  - Sevostianov, Igor
A1  - Requena, Guillermo
A1  - Bruno, Giovanni
T1  - Stress-induced damage evolution in cast AlSi12CuMgNi alloy with one- and two-ceramic reinforcements
JF  - Journal of materials science
N2  - Two composites, consisting of an as-cast AlSi12CuMgNi alloy reinforced with 15 vol% Al2O3 short fibres and with 7 vol% Al2O3 short fibres + 15 vol% SiC particles, were studied. Synchrotron computed tomography disclosed distribution, orientation, and volume fraction of the different phases. In-situ compression tests during neutron diffraction in direction parallel to the fibres plane revealed the load partition between phases. Internal damage (fragmentation) of the Si phase and Al2O3 fibres was directly observed in CT reconstructions. Significant debonding between Al matrix and SiC particles was also found. Finally, based on the Maxwell scheme, a micromechanical model was utilized for the new composite with two-ceramic reinforcements; it rationalizes the experimental data and predicts the evolution of all internal stress components in each phase.
Y1  - 2017
U6  - https://doi.org/10.1007/s10853-017-1182-7
SN  - 0022-2461
SN  - 1573-4803
VL  - 52
SP  - 10198
EP  - 10216
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Caetano, Daniel L. Z.
A1  - de Carvalho, Sidney J.
A1  - Metzler, Ralf
A1  - Cherstvy, Andrey G.
T1  - Critical adsorption of periodic and random polyampholytes onto charged surfaces
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - How different are the properties of critical adsorption of polyampholytes and polyelectrolytes onto charged surfaces? How important are the details of polyampholyte charge distribution on the onset of critical adsorption transition? What are the scaling relations governing the dependence of critical surface charge density on salt concentration in the surrounding solution? Here, we employ Metropolis Monte Carlo simulations and uncover the scaling relations for critical adsorption for quenched periodic and random charge distributions along the polyampholyte chains. We also evaluate and discuss the dependence of the adsorbed layer width on solution salinity and details of the charge distribution. We contrast our findings to the known results for polyelectrolyte adsorption onto oppositely charged surfaces, in particular, their dependence on electrolyte concentration.
Y1  - 2017
U6  - https://doi.org/10.1039/c7cp04040g
SN  - 1463-9076
SN  - 1463-9084
VL  - 19
SP  - 23397
EP  - 23413
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - THES
A1  - Can Ucar, Mehmet
T1  - Elastic interactions between antagonistic molecular motors
Y1  - 2017
ER  - 
TY  - JOUR
A1  - Cao, Xing
A1  - Shprits, Yuri Y.
A1  - Ni, Binbin
A1  - Zhelavskaya, Irina
T1  - Scattering of Ultra-relativistic Electrons in the Van Allen Radiation Belts Accounting for Hot Plasma Effects
JF  - Scientific reports
N2  - Electron flux in the Earth’s outer radiation belt is highly variable due to a delicate balance between competing acceleration and loss processes. It has been long recognized that Electromagnetic Ion Cyclotron (EMIC) waves may play a crucial role in the loss of radiation belt electrons. Previous theoretical studies proposed that EMIC waves may account for the loss of the relativistic electron population. However, recent observations showed that while EMIC waves are responsible for the significant loss of ultra-relativistic electrons, the relativistic electron population is almost unaffected. In this study, we provide a theoretical explanation for this discrepancy between previous theoretical studies and recent observations. We demonstrate that EMIC waves mainly contribute to the loss of ultra-relativistic electrons. This study significantly improves the current understanding of the electron dynamics in the Earth’s radiation belt and also can help us understand the radiation environments of the exoplanets and outer planets.
Y1  - 2017
U6  - https://doi.org/10.1038/s41598-017-17739-7
SN  - 2045-2322
VL  - 7
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Cappel, Ute B.
A1  - Svanstrom, Sebastian
A1  - Lanzilotto, Valeria
A1  - Johansson, Fredrik O. L.
A1  - Aitola, Kerttu
A1  - Philippe, Bertrand
A1  - Giangrisostomi, Erika
A1  - Ovsyannikov, Ruslan
A1  - Leitner, Torsten
A1  - Föhlisch, Alexander
A1  - Svensson, Svante
A1  - Martensson, Nils
A1  - Boschloo, Gerrit
A1  - Lindblad, Andreas
A1  - Rensmo, Hakan
T1  - Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells
JF  - ACS applied materials & interfaces
N2  - Metal halide perovskites have emerged as materials of high interest for solar energy-to-electricity conversion, and in particular, the use of mixed-ion structures has led to high power conversion efficiencies and improved stability. For this reason, it is important to develop means to obtain atomic level understanding of the photoinduced behavior of these materials including processes such as photoinduced phase separation and ion migration. In this paper, we implement a new methodology combining visible laser illumination of a mixed-ion perovskite ((FAP-bI(3))(0.85)(MAPbBr(3))(0.15)) with the element specificity and chemical sensitivity of core-level photoelectron spectroscopy. By carrying out measurements at a synchrotron beamline optimized for low X-ray fluxes, we are able to avoid sample changes due to X-ray illumination and are therefore able to monitor what sample changes are induced by visible illumination only. We find that laser illumination causes partially reversible chemistry in the surface region, including enrichment of bromide at the surface, which could be related to a phase separation into bromide- and iodide-rich phases. We also observe a partially reversible formation of metallic lead in the perovskite structure. These processes occur on the time scale of minutes during illumination. The presented methodology has a large potential for understanding light-induced chemistry in photoactive materials and could specifically be extended to systematically study the impact of morphology and composition on the photostability of metal halide perovskites.
KW  - photoelectron spectroscopy
KW  - laser illumination
KW  - lead halide perovskite
KW  - ion migration
KW  - phase separation
KW  - stability
Y1  - 2017
U6  - https://doi.org/10.1021/acsami.7b10643
SN  - 1944-8244
VL  - 9
SP  - 34970
EP  - 34978
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Cerruti, M.
A1  - Benbow, W.
A1  - Chen, Xu
A1  - Dumm, J. P.
A1  - Fortson, L. F.
A1  - Shahinyan, K.
T1  - Luminous and high-frequency peaked blazars: the origin of the gamma-ray emission from PKS 1424+240
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. The current generation of ground-based Cherenkov telescopes, together with the LAT instrument on-board the Fermi satellite, have greatly increased our knowledge of gamma-ray blazars. Among them, the high-frequency-peaked BL Lacertae object (HBL) PKS 1424+240 (z similar or equal to 0.6) is the farthest persistent emitter of very-high-energy (VHE; E >= 100 GeV) gamma-ray photons. Current emission models can satisfactorily reproduce typical blazar emission assuming that the dominant emission process is synchrotron-self-Compton (SSC) in HBLs; and external-inverse-Compton (EIC) in low-frequency-peaked BL Lacertae objects and flat-spectrum-radio-quasars. Alternatively, hadronic models are also able to correctly reproduce the gamma-ray emission from blazars, although they are in general disfavored for bright quasars and rapid flares. Aims. The blazar PKS 1424+240 is a rare example of a luminous HBL, and we aim to determine which is the emission process most likely responsible for its gamma-ray emission. This will impact more generally our comprehension of blazar emission models, and how they are related to the luminosity of the source and the peak frequency of the spectral energy distribution. Methods. We have investigated different blazar emission models applied to the spectral energy distribution of PKS 1424+240. Among leptonic models, we study a one-zone SSC model (including a systematic study of the parameter space), a two-zone SSC model, and an EIC model. We then investigated a blazar hadronic model, and finally a scenario in which the gamma-ray emission is associated with cascades in the line-of-sight produced by cosmic rays from the source. Results. After a systematic study of the parameter space of the one-zone SSC model, we conclude that this scenario is not compatible with gamma-ray observations of PKS 1424+240. A two-zone SSC scenario can alleviate this issue, as well as an EIC solution. For the latter, the external photon field is assumed to be the infra-red radiation from the dusty torus, otherwise the VHE gamma-ray emission would have been significantly absorbed. Alternatively, hadronic models can satisfactorily reproduce the gamma-ray emission from PKS 1424+240, both as in-source emission and as cascade emission.
KW  - relativistic processes
KW  - BL Lacertae objects: general
KW  - BL Lacertae objects: individual: PKS 1424+240
KW  - astroparticle physics
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201730799
SN  - 1432-0746
VL  - 606
SP  - 35411
EP  - 35418
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Cestnik, Rok
A1  - Rosenblum, Michael
T1  - Reconstructing networks of pulse-coupled oscillators from spike trains
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - We present an approach for reconstructing networks of pulse-coupled neuronlike oscillators from passive observation of pulse trains of all nodes. It is assumed that units are described by their phase response curves and that their phases are instantaneously reset by incoming pulses. Using an iterative procedure, we recover the properties of all nodes, namely their phase response curves and natural frequencies, as well as strengths of all directed connections.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevE.96.012209
SN  - 2470-0045
SN  - 2470-0053
VL  - 96
SP  - 3455
EP  - 3461
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Chechkin, Aleksei V.
A1  - Kantz, Holger
A1  - Metzler, Ralf
T1  - Ageing effects in ultraslow continuous time random walks
JF  - The European physical journal : B, Condensed matter and complex systems
N2  - In ageing systems physical observables explicitly depend on the time span elapsing between the original initiation of the system and the actual start of the recording of the particle motion. We here study the signatures of ageing in the framework of ultraslow continuous time random walk processes with super-heavy tailed waiting time densities. We derive the density for the forward or recurrent waiting time of the motion as function of the ageing time, generalise the Montroll-Weiss equation for this process, and analyse the ageing behaviour of the ensemble and time averaged mean squared displacements.
Y1  - 2017
U6  - https://doi.org/10.1140/epjb/e2017-80270-9
SN  - 1434-6028
SN  - 1434-6036
VL  - 90
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Chechkin, Aleksei V.
A1  - Seno, Flavio
A1  - Metzler, Ralf
A1  - Sokolov, Igor M.
T1  - Brownian yet Non-Gaussian Diffusion: From Superstatistics to Subordination of Diffusing Diffusivities
JF  - Physical review : X, Expanding access
N2  - A growing number of biological, soft, and active matter systems are observed to exhibit normal diffusive dynamics with a linear growth of the mean-squared displacement, yet with a non-Gaussian distribution of increments. Based on the Chubinsky-Slater idea of a diffusing diffusivity, we here establish and analyze a minimal model framework of diffusion processes with fluctuating diffusivity. In particular, we demonstrate the equivalence of the diffusing diffusivity process with a superstatistical approach with a distribution of diffusivities, at times shorter than the diffusivity correlation time. At longer times, a crossover to a Gaussian distribution with an effective diffusivity emerges. Specifically, we establish a subordination picture of Brownian but non-Gaussian diffusion processes, which can be used for a wide class of diffusivity fluctuation statistics. Our results are shown to be in excellent agreement with simulations and numerical evaluations.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevX.7.021002
SN  - 2160-3308
VL  - 7
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Chen, Zupeng
A1  - Savateev, Aleksandr
A1  - Pronkin, Sergey
A1  - Papaefthimiou, Vasiliki
A1  - Wolff, Christian Michael
A1  - Willinger, Marc Georg
A1  - Willinger, Elena
A1  - Neher, Dieter
A1  - Antonietti, Markus
A1  - Dontsova, Dariya
T1  - "The Easier the Better" Preparation of Efficient Photocatalysts-Metastable Poly(heptazine imide) Salts
JF  - Advanced materials
N2  - Cost-efficient, visible-light-driven hydrogen production from water is an attractive potential source of clean, sustainable fuel. Here, it is shown that thermal solid state reactions of traditional carbon nitride precursors (cyanamide, melamine) with NaCl, KCl, or CsCl are a cheap and straightforward way to prepare poly(heptazine imide) alkali metal salts, whose thermodynamic stability decreases upon the increase of the metal atom size. The chemical structure of the prepared salts is confirmed by the results of X-ray photoelectron and infrared spectroscopies, powder X-ray diffraction and electron microscopy studies, and, in the case of sodium poly(heptazine imide), additionally by atomic pair distribution function analysis and 2D powder X-ray diffraction pattern simulations. In contrast, reactions with LiCl yield thermodynamically stable poly(triazine imides). Owing to the metastability and high structural order, the obtained heptazine imide salts are found to be highly active photo-catalysts in Rhodamine B and 4-chlorophenol degradation, and Pt-assisted sacrificial water reduction reactions under visible light irradiation. The measured hydrogen evolution rates are up to four times higher than those provided by a benchmark photocatalyst, mesoporous graphitic carbon nitride. Moreover, the products are able to photocatalytically reduce water with considerable reaction rates, even when glycerol is used as a sacrificial hole scavenger.
KW  - carbon nitride
KW  - glycerol oxidation
KW  - mesocrystals
KW  - poly(heptazine imide)
KW  - water reduction reactions
Y1  - 2017
U6  - https://doi.org/10.1002/adma.201700555
SN  - 0935-9648
SN  - 1521-4095
VL  - 29
SP  - 21800
EP  - 21806
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Cherstvy, Andrey G.
T1  - Shape Morphologies of Icosahedral Two-Component Vesicles
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - What are the features of partitioning of crystalline materials on the surface of a two-component icosahedral vesicle? We model the response of the rigid hardly stretchable crystalline icosahedra upon addition of a softer component on its surface. We demonstrate how the soft phase "invades" the shell regions with the highest elastic energy density around 12 5-fold topological defects. We explore the phase diagram of these inhomogeneous shells as a function of the soft material fraction, shell radius, and elastic moduli of the two phases. The findings are compared with the recent computer simulation findings, and their biological relevance, for example, for the structure of icosahedral viruses, is also discussed.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.jpcb.7b02440
SN  - 1520-6106
VL  - 121
SP  - 7484
EP  - 7491
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Cherstvy, Andrey G.
A1  - Vinod, Deepak
A1  - Aghion, Erez
A1  - Chechkin, Aleksei V.
A1  - Metzler, Ralf
T1  - Time averaging, ageing and delay analysis of financial time series
JF  - New journal of physics
N2  - We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black–Scholes–Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.
KW  - time averaging
KW  - diffusion
KW  - geometric Brownian motion
KW  - financial time series
Y1  - 2017
U6  - https://doi.org/10.1088/1367-2630/aa7199
SN  - 1367-2630
VL  - 19
SP  - 1
EP  - 11
PB  - IOP
CY  - London
ER  - 
TY  - GEN
A1  - Cherstvy, Andrey G.
A1  - Vinod, Deepak
A1  - Aghion, Erez
A1  - Chechkin, Aleksei V.
A1  - Metzler, Ralf
T1  - Time averaging, ageing and delay analysis of financial time series
N2  - We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black–Scholes–Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 347 
KW  - diffusion
KW  - financial time series
KW  - geometric Brownian motion
KW  - time averaging
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400541
ER  - 
TY  - JOUR
A1  - Cherstvy, Andrey G.
A1  - Vinod, Deepak
A1  - Aghion, Erez
A1  - Chechkin, Aleksei V.
A1  - Metzler, Ralf
T1  - Time averaging, ageing and delay analysis of financial time series
JF  - New journal of physics : the open-access journal for physics
N2  - We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black-Scholes-Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.
KW  - time averaging
KW  - diffusion
KW  - geometric Brownian motion
KW  - financial time series
Y1  - 2017
U6  - https://doi.org/10.1088/1367-2630/aa7199
SN  - 1367-2630
VL  - 19
SP  - 135
EP  - 147
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Collado-Fregoso, Elisa
A1  - Hood, Samantha N.
A1  - Shoaee, Safa
A1  - Schröder, Bob C.
A1  - McCulloch, Iain
A1  - Kassal, Ivan
A1  - Neher, Dieter
A1  - Durrant, James R.
T1  - Intercalated vs Nonintercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited
JF  - The journal of physical chemistry letters
N2  - In this Letter, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and nonintercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the nonintercalated system and almost vanishes when energetic disorder is included in the model. Despite these differences, both femtosecond-resolved transient absorption spectroscopy (TAS) and time-delayed collection field (TDCF) exhibit extensive first-order losses in both systems, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene-aggregated domains (1:4 PBTTT:PC70BM) is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short-circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges and their impact upon charge generation and recombination.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.jpclett.7b01571
SN  - 1948-7185
VL  - 8
SP  - 4061
EP  - 4068
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Cooper, Ryan C.
A1  - Bruno, Giovanni
A1  - Wheeler, M. R.
A1  - Pandey, A.
A1  - Watkins, T. R.
A1  - Shyarn, A.
T1  - Effect of microcracking on the uniaxial tensile response of beta-eucryptite ceramics
BT  - Experiments and constitutive model
JF  - Acta Materialia
N2  - A constitutive model for the nonlinear or "pseudoplastic" mechanical behavior in a linear-elastic solid with thermally induced microcracks is developed and applied to experimental results. The model is termed strain dependent microcrack density approximation (SDMDA) and is an extension of the modified differential scheme that describes the slope of the stress-strain curves of microcracked solids. SDMDA allows a continuous variation in the microcrack density with tensile loading. Experimental uniaxial tensile response of beta-eucryptite glass and ceramics with controlled levels of microcracking is reported. It is demonstrated that SDMDA can well describe the extent of non-linearity in the experimental uniaxial tensile response of beta-eucryptite with varying levels of microcracking. The advantages of the SDMDA are discussed in regard to tensile loading.
KW  - behavior
Y1  - 2017
U6  - https://doi.org/10.1016/j.actamat.2017.06.033
SN  - 1359-6454
SN  - 1873-2453
VL  - 135
SP  - 361
EP  - 371
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Couto, Rafael C.
A1  - Cruz, Vinicius V.
A1  - Ertan, Emelie
A1  - Eckert, Sebastian
A1  - Fondell, Mattis
A1  - Dantz, Marcus
A1  - Kennedy, Brian
A1  - Schmitt, Thorsten
A1  - Pietzsch, Annette
A1  - Guimaraes, Freddy F.
A1  - Agren, Hans
A1  - Odelius, Michael
A1  - Kimberg, Victor
A1  - Föhlisch, Alexander
T1  - Selective gating to vibrational modes through resonant X-ray scattering
JF  - Nature Communications
N2  - The dynamics of fragmentation and vibration of molecular systems with a large number of coupled degrees of freedom are key aspects for understanding chemical reactivity and properties. Here we present a resonant inelastic X-ray scattering (RIXS) study to show how it is possible to break down such a complex multidimensional problem into elementary components. Local multimode nuclear wave packets created by X-ray excitation to different core-excited potential energy surfaces (PESs) will act as spatial gates to selectively probe the particular ground-state vibrational modes and, hence, the PES along these modes. We demonstrate this principle by combining ultra-high resolution RIXS measurements for gas-phase water with state-of-the-art simulations.
Y1  - 2017
U6  - https://doi.org/10.1038/ncomms14165
SN  - 2041-1723
VL  - 8
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - GEN
A1  - Couto, Rafael C.
A1  - Cruz, Vinicius V.
A1  - Ertan, Emelie
A1  - Eckert, Sebastian
A1  - Fondell, Mattis
A1  - Dantz, Marcus
A1  - Kennedy, Brian
A1  - Schmitt, Thorsten
A1  - Pietzsch, Annette
A1  - Guimarães, Freddy F.
A1  - Ågren, Hans
A1  - Gel’mukhanov, Faris
A1  - Odelius, Michael
A1  - Kimberg, Victor
A1  - Föhlisch, Alexander
T1  - Selective gating to vibrational modes through resonant X-ray scattering
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The dynamics of fragmentation and vibration of molecular systems with a large number of coupled degrees of freedom are key aspects for understanding chemical reactivity and properties. Here we present a resonant inelastic X-ray scattering (RIXS) study to show how it is possible to break down such a complex multidimensional problem into elementary components. Local multimode nuclear wave packets created by X-ray excitation to different core-excited potential energy surfaces (PESs) will act as spatial gates to selectively probe the particular ground-state vibrational modes and, hence, the PES along these modes. We demonstrate this principle by combining ultra-high resolution RIXS measurements for gas-phase water with state-of-the-art simulations.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1124 
KW  - potential-energy surface
KW  - raman-scattering
KW  - water-vapor
KW  - spectroscopy
KW  - chemistry
KW  - molecule
KW  - spectrum
KW  - CM(-1)
KW  - states
KW  - NM
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436926
SN  - 1866-8372
IS  - 1124
ER  - 
TY  - JOUR
A1  - Dahlke, Sandro
A1  - Maturilli, Marion
T1  - Contribution of atmospheric advection to the amplified winter warming in the arctic north atlantic region
JF  - Advances in meteorology
N2  - Arctic Amplification of climate warming is caused by various feedback processes in the atmosphere-ocean-ice system and yields the strongest temperature increase during winter in the Arctic North Atlantic region. In our study, we attempt to quantify the advective contribution to the observed atmospheric warming in the Svalbard area. Based on radiosonde measurements from Ny-Ålesund, a strong dependence of the tropospheric temperature on the synoptic flow direction is revealed. Using FLEXTRA backward trajectories, an increase of advection from the lower latitude Atlantic region towards Ny-Ålesund is found that is attributed to a change in atmospheric circulation patterns. We find that about one-quarter (0.45 K per decade) of the observed atmospheric winter near surface warming trend in the North Atlantic region of the Arctic (2 K per decade) is due to increased advection of warm and moist air from the lower latitude Atlantic region, affecting the entire troposphere.
Y1  - 2017
U6  - https://doi.org/10.1155/2017/4928620
SN  - 1687-9309
SN  - 1687-9317
PB  - Hindawi Publ. Corp.
CY  - New York
ER  - 
TY  - JOUR
A1  - Davidsen, Joern
A1  - Kwiatek, Grzegorz
A1  - Charalampidou, Elli-Maria
A1  - Goebel, Thomas H. W.
A1  - Stanchits, Sergei
A1  - Rueck, Marc
A1  - Dresen, Georg
T1  - Triggering Processes in Rock Fracture
JF  - Physical review letters
N2  - We study triggering processes in triaxial compression experiments under a constant displacement rate on sandstone and granite samples using spatially located acoustic emission events and their focal mechanisms. We present strong evidence that event-event triggering plays an important role in the presence of large-scale or macrocopic imperfections, while such triggering is basically absent if no significant imperfections are present. In the former case, we recover all established empirical relations of aftershock seismicity including the Gutenberg-Richter relation, a modified version of the Omori-Utsu relation and the productivity relation-despite the fact that the activity is dominated by compaction-type events and triggering cascades have a swarmlike topology. For the Gutenberg-Richter relations, we find that the b value is smaller for triggered events compared to background events. Moreover, we show that triggered acoustic emission events have a focal mechanism much more similar to their associated trigger than expected by chance.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevLett.119.068501
SN  - 0031-9007
SN  - 1079-7114
VL  - 119
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - De Angelis, A.
A1  - Tatischeff, V.
A1  - Tavani, M.
A1  - Oberlack, U.
A1  - Grenier, I.
A1  - Hanloni, L.
A1  - Walter, R.
A1  - Argan, A.
A1  - Von Ballmoos, P.
A1  - Bulgarelli, A.
A1  - Donnarumma, I.
A1  - Hernanz, M.
A1  - Kuvvetli, I.
A1  - Pearce, M.
A1  - Zdziarski, A.
A1  - Aboudan, A.
A1  - Ajello, M.
A1  - Ambrosi, G.
A1  - Bernard, D.
A1  - Bernardini, E.
A1  - Bonvicini, V.
A1  - Brogna, A.
A1  - Branchesi, M.
A1  - Budtz-Jorgensen, C.
A1  - Bykov, A. M.
A1  - Campana, R.
A1  - Cardillo, M.
A1  - Coppi, P.
A1  - De Martino, D.
A1  - Diehl, R.
A1  - Doro, M.
A1  - Fioretti, V.
A1  - Funk, S.
A1  - Ghisellini, G.
A1  - Grove, E.
A1  - Hamadache, C.
A1  - Hartmann, D. H.
A1  - Hayashida, M.
A1  - Isern, J.
A1  - Kanbach, G.
A1  - Kiener, J.
A1  - Knodlseder, J.
A1  - Labanti, C.
A1  - Laurent, P.
A1  - Limousin, O.
A1  - Longo, F.
A1  - Mannheim, K.
A1  - Marisaldi, M.
A1  - Martinez, M.
A1  - Mazziotta, Mario Nicola
A1  - McEnery, J.
A1  - Mereghetti, S.
A1  - Minervini, G.
A1  - Moiseev, A.
A1  - Morselli, A.
A1  - Nakazawa, K.
A1  - Orleanski, P.
A1  - Paredes, J. M.
A1  - Patricelli, B.
A1  - Pevre, J.
A1  - Piano, G.
A1  - Pohl, Martin
A1  - Ramarijaona, H.
A1  - Rando, R.
A1  - Reichardt, I.
A1  - Roncadelli, M.
A1  - Silva, R.
A1  - Tavecchio, F.
A1  - Thompson, D. J.
A1  - Turolla, R.
A1  - Ulyanov, A.
A1  - Vacchi, A.
A1  - Wu, X.
A1  - Zoglauer, A.
T1  - The e-ASTROGAM mission Exploring the extreme Universe with gamma rays in the MeV - GeV range
JF  - Experimental astronomy : an international journal on astronomical instrumentation and data analysis
N2  - e-ASTROGAM (‘enhanced ASTROGAM’) is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV – the lower energy limit can be pushed to energies as low as 150 keV, albeit with rapidly degrading angular resolution, for the tracker, and to 30 keV for calorimetric detection. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA, ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and the promise of eLISA.
KW  - High-Energy Gamma-Ray Astronomy
KW  - High-Energy Astrophysics
KW  - Nuclear Astrophysics
KW  - Compton and Pair Creation Telescope
KW  - Gamma-Ray Bursts
KW  - Active Galactic Nuclei
KW  - Jets
KW  - Outflows
KW  - Multiwavelength Observations of the Universe
KW  - Counterparts of gravitational waves
KW  - Fermi
KW  - Dark Matter
KW  - Nucleosynthesis
KW  - Early Universe
KW  - Supernovae
KW  - Cosmic Rays
KW  - Cosmic Antimatter
Y1  - 2017
U6  - https://doi.org/10.1007/s10686-017-9533-6
SN  - 0922-6435
SN  - 1572-9508
VL  - 44
SP  - 25
EP  - 82
PB  - Springer
CY  - Dordrecht
ER  -