TY  - JOUR
A1  - Abdalla, Hassan E.
A1  - Abramowski, A.
A1  - Aharonian, Felix A.
A1  - Benkhali, F. Ait
A1  - Akhperjanian, A. G.
A1  - Andersson, T.
A1  - Anguener, E. O.
A1  - Arakawa, M.
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  - Bernloehr, K.
A1  - Blackwell, R.
A1  - Boettcher, M.
A1  - Boisson, C.
A1  - Bolmont, J.
A1  - Bonnefoy, S.
A1  - Bordas, Pol
A1  - Bregeon, J.
A1  - Brun, F.
A1  - Brun, P.
A1  - Bryan, M.
A1  - Buechele, M.
A1  - Bulik, T.
A1  - Capasso, M.
A1  - Carr, J.
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chakraborty, N.
A1  - Chaves, R. C. G.
A1  - Chen, A.
A1  - Chevalier, J.
A1  - Coffaro, 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  - 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, J. A.
A1  - Hofmann, W.
A1  - Hoischen, Clemens
A1  - Holch, T. L.
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  - Krueger, 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, D. A.
A1  - Santangelo, A.
A1  - Sasaki, M.
A1  - Schlickeiser, R.
A1  - Schuessler, 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, I.
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  - Venters, 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  - Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with HESS
JF  - Astronomy and astrophysics : an international weekly journal
N2  - The diffuse very high-energy (VHE; > 100 GeV) gamma-ray emission observed in the central 200 pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal distance of about 130 pc to the Galactic centre (GC), where the flux rapidly decreases. This was initially interpreted as the result of a burst-like injection of energetic particles 104 yr ago, but a recent more sensitive H.E.S.S. analysis revealed that the cosmic-ray (CR) density profile drops with the distance to the centre, making data compatible with a steady cosmic PeVatron at the GC. In this paper, we extend this analysis to obtain, for the first time, a detailed characterisation of the correlation with matter and to search for additional features and individual gamma-ray sources in the inner 200 pc. Taking advantage of 250 h of H.E.S.S. data and improved analysis techniques, we perform a detailed morphology study of the diffuse VHE emission observed from the GC ridge and reconstruct its total spectrum. To test the various contributions to the total gamma-ray emission, we used an iterative 2D maximum-likelihood approach that allows us to build a phenomenological model of the emission by summing a number of different spatial components. We show that the emission correlated with dense matter covers the full CMZ and that its flux is about half the total diffuse emission flux. We also detect some emission at higher latitude that is likely produced by hadronic collisions of CRs in less dense regions of the GC interstellar medium. We detect an additional emission component centred on the GC and extending over about 15 pc that is consistent with the existence of a strong CR density gradient and confirms the presence of a CR accelerator at the very centre of our Galaxy. We show that the spectrum of full ridge diffuse emission is compatible with that previously derived from the central regions, suggesting that a single population of particles fills the entire CMZ. Finally, we report the discovery of a VHE gamma-ray source near the GC radio arc and argue that it is produced by the pulsar wind nebula candidate G0.13-0.11.
KW  - gamma rays: general
KW  - gamma rays: ISM
KW  - Galaxy: center
KW  - cosmic rays
Y1  - 2018
U6  - https://doi.org/10.1051/0004-6361/201730824
SN  - 1432-0746
VL  - 612
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - GEN
A1  - Barniske, Andreas
A1  - Oskinova, Lida
A1  - Hamann, Wolf-Rainer
T1  - Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas (vol 486, pg 971, 2008)
T2  - Physical chemistry, chemical physics : a journal of European Chemical Societies
KW  - stars: Wolf-Rayet
KW  - HII regions
KW  - Galaxy: center
KW  - stars: individual: WR 102ka
KW  - stars: individual: WR 102c
KW  - errata, addenda
Y1  - 2016
U6  - https://doi.org/10.1051/0004-6361/200809568e
SN  - 1432-0746
VL  - 587
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Steinke, Martin
A1  - Oskinova, Lida
A1  - Hamann, Wolf-Rainer
A1  - Sander, Andreas Alexander Christoph
A1  - Liermann, A.
A1  - Todt, Helge Tobias
T1  - Analysis of the WN star WR102c, its WR nebula, and the associated cluster of massive stars in the Sickle Nebula
JF  - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth
N2  - Context. The massive Wolf-Rayet type star WR102c is located near the Quintuplet Cluster, one of the three massive star clusters in the Galactic centre region. Previous studies indicated that WR102c may have a dusty circumstellar nebula and is among the main ionising sources of the Sickle Nebula associated with the Quintuplet Cluster. Aims. The goals of our study are to derive the stellar parameters of WR102c from the analysis of its spectrum and to investigate its stellar and nebular environment. Methods. We obtained observations with the ESO VLT integral field spectrograph SINFONI in the K-band, extracted the stellar spectra, and analysed them by means of stellar atmosphere models. Results. Our new analysis supersedes the results previously reported for WR102c. We significantly decrease its bolometric luminosity and hydrogen content. We detect four early OB type stars close to WR102c. These stars have radial velocities similar to that of WR102c. We suggest that together with WR102c these stars belong to a distinct star cluster with a total mass of similar to 1000 M-circle dot. We identify a new WR nebula around WR102c in the SINFONI map of the di ff use Br gamma emission and in the HST Pa ff images. The Br gamma line at di ff erent locations is not significantly broadened and similar to the width of nebular emission elsewhere in the H i i region around WR102c. Conclusions. The massive star WR102c located in the Galactic centre region resides in a star cluster containing additional early-type stars. The stellar parameters of WR102c are typical for hydrogen-free WN6 stars. We identify a nebula surrounding WR102c that has a morphology similar to other nebulae around hydrogen-free WR stars, and propose that the formation of this nebula is linked to interaction of the fast stellar wind with the matter ejected at a previous evolutionary stage of WR102c.
KW  - stars: early-type
KW  - stars: individual: WR 102c
KW  - stars: Wolf
KW  - Rayet
KW  - Galaxy: center
KW  - HII regions
KW  - infrared: stars
Y1  - 2016
U6  - https://doi.org/10.1051/0004-6361/201527692
SN  - 1432-0746
VL  - 588
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Archer, A.
A1  - Benbow, W.
A1  - Bird, R.
A1  - Buchovecky, M.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Chen, Xuhui
A1  - Ciupik, L.
A1  - Collins-Hughes, E.
A1  - Connolly, M. P.
A1  - Eisch, J. D.
A1  - Falcone, A.
A1  - Feng, Q.
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  - Gyuk, G.
A1  - Hakansson, Nils
A1  - Hanna, D.
A1  - Holder, J.
A1  - Humensky, T. B.
A1  - Huetten, M.
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  - McArthur, S.
A1  - McCann, A.
A1  - Meagher, K.
A1  - Millis, J.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Park, N.
A1  - Pelassa, V.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Ratliff, G.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rousselle, J.
A1  - Santander, M.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Smith, A. W.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Vassiliev, V. V.
A1  - Wakely, S. P.
A1  - Weiner, O. M.
A1  - Weinstein, A.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zitzer, B.
A1  - Yusef-Zadeh, F.
T1  - TEV GAMMA-RAY OBSERVATIONS OF THE GALACTIC CENTER RIDGE BY VERITAS
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The Galactic Center ridge has been observed extensively in the past by both GeV and TeV gamma-ray instruments revealing a wealth of structure, including a diffuse component and the point sources G0.9+0.1 (a composite supernova remnant) and Sgr A* (believed to be associated with the supermassive black hole located at the center of our Galaxy). Previous very high energy (VHE) gamma-ray observations with the H.E.S.S.. experiment have also detected an extended TeV gamma-ray component along the Galactic plane in the >300 GeV gamma-ray regime. Here we report on observations of the Galactic Center ridge from 2010 to 2014 by the VERITAS telescope array in the >2 TeV energy range. From these observations we (1) provide improved measurements of the differential energy spectrum for Sgr A* in the >2 TeV gamma-ray regime, (2) provide a detection in the >2 TeV gamma-ray emission from the composite SNR G0.9+0.1 and an improved determination of its multi-TeV gamma-ray energy spectrum, and. (3) report on the detection of VER J1746-289, a localized enhancement of >2 TeV gamma-ray emission along the Galactic plane.
KW  - Galaxy: center
KW  - gamma rays: general
KW  - supernovae: individual (G0.9+0.1)
Y1  - 2016
U6  - https://doi.org/10.3847/0004-637X/821/2/129
SN  - 0004-637X
SN  - 1538-4357
VL  - 821
SP  - 162
EP  - 167
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Archer, A.
A1  - Barnacka, Anna
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Berger, K.
A1  - Bird, R.
A1  - Biteau, Jonathan
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Chen, W.
A1  - Chen, Xiaoming
A1  - Ciupik, L.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Dickinson, H. J.
A1  - Dumm, J.
A1  - Eisch, J. D.
A1  - Falcone, A.
A1  - Federici, Simone
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Galante, N.
A1  - Griffin, S.
A1  - Griffiths, S. T.
A1  - Grube, J.
A1  - Gyuk, G.
A1  - Hakansson, Nils
A1  - Hanna, D.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kar, P.
A1  - Kertzman, M.
A1  - Khassen, Y.
A1  - Kieda, D.
A1  - Krawczynski, H.
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  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Perkins, J. S.
A1  - Pohl, Manuela
A1  - Popkow, A.
A1  - Prokoph, H.
A1  - Pueschel, Elisa
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Rajotte, J.
A1  - Reyes, L. C.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Smith, A. W.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Varlotta, A.
A1  - Vincent, S.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Welsing, R.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Zajczyk, A.
A1  - Zitzer, B.
T1  - Very-high energy observations of the galactic center region by veritas IN 2010-2012
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - The Galactic center is an interesting region for high-energy (0.1-100 GeV) and very-high-energy (E > 100 GeV) gamma-ray observations. Potential sources of GeV/TeV gamma-ray emission have been suggested, e.g., the accretion of matter onto the supermassive black hole, cosmic rays from a nearby supernova remnant (e.g., Sgr A East), particle acceleration in a plerion, or the annihilation of dark matter particles. The Galactic center has been detected by EGRET and by Fermi/LAT in the MeV/GeV energy band. At TeV energies, the Galactic center was detected with moderate significance by the CANGAROO and Whipple 10 m telescopes and with high significance by H.E.S.S., MAGIC, and VERITAS. We present the results from three years of VERITAS observations conducted at large zenith angles resulting in a detection of the Galactic center on the level of 18 standard deviations at energies above similar to 2.5 TeV. The energy spectrum is derived and is found to be compatible with hadronic, leptonic, and hybrid emission models discussed in the literature. Future, more detailed measurements of the high-energy cutoff and better constraints on the high-energy flux variability will help to refine and/or disentangle the individual models.
KW  - astroparticle physics
KW  - black hole physics
KW  - Galaxy: center
KW  - gamma rays: galaxies
KW  - methods: data analysis
KW  - radiation mechanisms: non-thermal
Y1  - 2014
U6  - https://doi.org/10.1088/0004-637X/790/2/149
SN  - 0004-637X
SN  - 1538-4357
VL  - 790
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -