TY  - JOUR
A1  - Christensen, Lise Bech
A1  - Schulte-Ladbeck, R. E.
A1  - Sanchez, Sebastian F.
A1  - Becker, Thomas
A1  - Jahnke, Knud
A1  - Kelz, A.
A1  - Roth, Martin M.
A1  - Wisotzki, Lutz
T1  - Abundances and kinematics of a candidate sub-damped Lymana galaxy toward PHL 1226
N2  - The spectrum of the quasar PHL 1226 is known to have a strong Mg II and sub-damped Lymanalpha (sub-DLA) absorption line system with N(H I) = (5 +/- 2) x 10(19) cm(-2) at z = 0.1602. Using integral field spectra from the Potsdam Multi Aperture Spectrophotometer (PMAS) we investigate a galaxy at an impact parameter of 6".4 which is most probably responsible for the absorption lines. A fainter galaxy at a similar redshift and a slightly larger distance from the QSO is known to exist, but we assume that the absorption is caused by the more nearby galaxy. From optical Balmer lines we estimate an intrinsic reddening consistent with 0, and a moderate star formation rate of 0.5 M-circle dot yr(-1) is inferred from the Ha luminosity. Using nebular emission line ratios we find a solar oxygen abundance 12 + log (O/H) = 8.7 +/- 0.1 and a solar nitrogen to oxygen abundance ratio log (N/O) = -1.0 +/- 0.2. This abundance is larger than those of all known sub-DLA systems derived from analyses of metal absorption lines in quasar spectra. On the other hand, the properties are compatible with the most metal rich galaxies responsible for strong Mg II absorption systems. These two categories can be reconciled if we assume an abundance gradient similar to local galaxies. Under that assumption we predict abundances 12 + log (O/H) = 7.1 and log (N/O) = -1.9 for the sub-DLA cloud, which is similar to high redshift DLA and sub-DLA systems. We find evidence for a rotational velocity of similar to200 km s(-1) over a length of similar to7 kpc. From the geometry and kinematics of the galaxy we estimate that the absorbing cloud does not belong to a rotating disk, but could originate in a rotating halo
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Wisotzki, Lutz
A1  - Becker, Thomas
A1  - Christensen, Lise Bech
A1  - Helms, Andreas
A1  - Jahnke, Knud
A1  - Kelz, A.
A1  - Roth, Martin M.
A1  - Sanchez, Sebastian F.
T1  - Integral-field spectrophotometry of the quadruple QSO HE 0435-1223 : Evidence for microlensing
N2  - We present the first spatially resolved spectroscopic observations of the recently discovered quadruple QSO and gravitational lens HE 0435-1223. Using the Potsdam Multi-Aperture Spectrophotometer (PMAS), we show that all four QSO components have very similar but not identical spectra. In particular, the spectral slopes of components A, B, and D are indistinguishable, implying that extinction due to dust plays no major role in the lensing galaxy. While also the emission line profiles are identical within the error bars, as expected from lensing, the equivalent widths show significant differences between components. Most likely, microlensing is responsible for this phenomenon. This is also consistent with the fact that component D, which shows the highest relative continuum level, has brightened by 0.07 mag since Dec. 2001. We find that the emission line flux ratios between the components are in better agreement with simple lens models than broad band or continuum measurements, but that the discrepancies between model and data are still unacceptably large. Finally, we present a detection of the lensing galaxy, although this is close to the limits of the data. Comparing with a model galaxy spectrum, we obtain a redshift estimate of zlens=0.44+/- 0.02.
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Christensen, Lise Bech
A1  - Sanchez, Sebastian F.
A1  - Jahnke, Knud
A1  - Becker, Thomas
A1  - Wisotzki, Lutz
A1  - Kelz, A.
A1  - Popovic, L. C.
A1  - Roth, Martin M.
T1  - Integral field spectroscopy of extended Ly alpha emission from the DLA galaxy in Q2233+131
N2  - This paper presents observations of an extended Lyman-alpha emission nebula surrounding the galaxy responsible for the Damped Lyman-alpha Absorption (DLA) line in the spectrum of the quasar Q2233+131. With the Potsdam Multi Aperture Spectrophotometer (PMAS) we measure the properties of the extended Lyalpha emission in an area of 3" x 5" having a total line flux of (2.8 +/- 0.3) x 10(-16) erg cm(-2) s(-1), which at redshift z = 3.15 corresponds to a luminosity of (2.4(-0.2)(+0.3)) x 10(43) erg s(-1) and a size of 23 x 38 kpc. The location of the emission is spatially coincident with the previously detected DLA galaxy, but extends significantly beyond its limb. We argue that the Lya emission is likely to be caused by an outflow from the DLA galaxy, presumably powered by star formation. In the case of negligible dust extinction, the Lya luminosity indicates a star-formation rate of 19 +/- 10 M-. yr(-1) consistent with that derived from the UV continuum flux from the parent galaxy. The wind velocity indicated by the integral field spectra is of the order of several hundred km s(-1). We find no indication of emission originating in a rotating disk
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Wisotzki, Lutz
A1  - Becker, Thomas
A1  - Christensen, Lise Bech
A1  - Jahnke, Knud
A1  - Helms, Andreas
A1  - Kelz, A.
A1  - Roth, Martin M.
A1  - Sanchez, Sebastian F.
T1  - Integral field spectrophotometry of gravitationally lensed QSOs with PMAS
N2  - We present spatially resolved spectrophotometric observations of multiply imaged QSOs, using the Potsdam Multi- Aperture Spectrophotometer (PMAS), with the intention to search for spectral differences between components indicative of either microlensing or dust extinction. For the quadruple QSO HE 0435-1223 we find that the continuum shapes are indistinguishable, therefore differential extinction is negligible. The equivalent widths of the broad emission lines are however significantly different, and we argue that this is most likely due to microlensing. Contrariwise, the two components of the well-known object UM 673 have virtually identical emission line properties, but the continuum slopes differ significantly and indicate different dust extinction along both lines of sight
Y1  - 2004
SN  - 0004-6337
ER  - 
TY  - JOUR
A1  - Christensen, Lise Bech
A1  - Sanchez, Sebastian F.
A1  - Jahnke, Knud
A1  - Becker, Thomas
A1  - Kelz, A.
A1  - Wisotzki, Lutz
A1  - Roth, Martin M.
T1  - Integral field observations of damped Lyman-alpha galaxies
N2  - We report preliminary results from a targeted investigation on quasars containing damped Lyman-alpha absorption (DLA) lines as well strong metal absorption lines, carried out with the Potsdam Multi Aperture Spectrophotometer (PMAS). We search for line-emitting objects at the same redshift as the absorption lines and close to the line of sight of the QSOs. We have observed and detected the already confirmed absorbing galaxies in Q2233+131 (Z(abs) = 3.15) and Q0151+045 (Z(abs),= 0.168), while failing to find spectral signatures for the z = 0.091 absorber in Q0738+313. From the Q2233+131 DLA galaxy, we have detected extended Lyalpha emission from an area of 3" x 5"
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Jahnke, Knud
A1  - Wisotzki, Lutz
A1  - Sanchez, Sebastian F.
A1  - Christensen, Lise Bech
A1  - Becker, Thomas
A1  - Kelz, A.
A1  - Roth, Martin M.
T1  - Integral field spectroscopy of QSO host galaxies
N2  - We describe a project to study the state of the ISM in similar to20 low redshift (z < 0.3) QSO host galaxies observed with the PMAS integral field spectrograph. We describe the development of the method to access the stellar and gas components of the spectrum without the strong nuclear emission, in order to access the host galaxy properties in the central region. It shows that integral field spectroscopy promises to be very efficient in studying the gas distribution and its velocity field, and also the spatially resolved stellar population in the host galaxies of luminous AGN
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Wisotzki, Lutz
A1  - Schechter, P. L.
A1  - Chen, H. W.
A1  - Richstone, D.
A1  - Jahnke, Knud
A1  - Sanchez, Sebastian F.
A1  - Reimers, Dieter
T1  - HE 0047-1756 : a new gravitationally lensed double QSO
N2  - The quasar HE 0047-1756, at z = 1.67, is found to be split into two images 1."144 apart by an intervening galaxy acting as a gravitational lens. The flux ratio for the two components is roughly 3.5:1, depending slightly upon wavelength. The lensing galaxy is seen on images obtained in the i (800 nm) and K-s bands (2.1 mum); there is also a nearby faint object which may be responsible for some shear. The spectra of the two quasar images are nearly identical, but the emission line ratio between the two components scale differently from the continuum. Moreover, the fainter component has a bluer continuum slope than the brighter one. We argue that these small differences are probably due to microlensing. There is evidence for a partial Einstein ring emanating from the brighter image toward the fainter one
Y1  - 2004
SN  - 0004-6361
ER  - 
TY  - JOUR
A1  - Wolf, Thomas J. A.
A1  - Sanchez, David M.
A1  - Yang, J.
A1  - Parrish, R. M.
A1  - Nunes, J. P. F.
A1  - Centurion, M.
A1  - Coffee, R.
A1  - Cryan, J. P.
A1  - Gühr, Markus
A1  - Hegazy, Kareem
A1  - Kirrander, Adam
A1  - Li, R. K.
A1  - Ruddock, J.
A1  - Shen, Xiaozhe
A1  - Vecchione, T.
A1  - Weathersby, S. P.
A1  - Weber, Peter M.
A1  - Wilkin, K.
A1  - Yong, Haiwang
A1  - Zheng, Q.
A1  - Wang, X. J.
A1  - Minitti, Michael P.
A1  - Martinez, Todd J.
T1  - The photochemical ring-opening of 1,3-cyclohexadiene imaged by ultrafast electron diffraction
JF  - Nature chemistry
N2  - The ultrafast photoinduced ring-opening of 1,3-cyclohexadiene constitutes a textbook example of electrocyclic reactions in organic chemistry and a model for photobiological reactions in vitamin D synthesis. Although the relaxation from the photoexcited electronic state during the ring-opening has been investigated in numerous studies, the accompanying changes in atomic distance have not been resolved. Here we present a direct and unambiguous observation of the ring-opening reaction path on the femtosecond timescale and subangstrom length scale using megaelectronvolt ultrafast electron diffraction. We followed the carbon-carbon bond dissociation and the structural opening of the 1,3-cyclohexadiene ring by the direct measurement of time-dependent changes in the distribution of interatomic distances. We observed a substantial acceleration of the ring-opening motion after internal conversion to the ground state due to a steepening of the electronic potential gradient towards the product minima. The ring-opening motion transforms into rotation of the terminal ethylene groups in the photoproduct 1,3,5-hexatriene on the subpicosecond timescale.
KW  - Organic chemistry
KW  - Photochemistry
KW  - Physical chemistry
KW  - Theoretical chemistry
Y1  - 2019
U6  - https://doi.org/10.1038/s41557-019-0252-7
SN  - 1755-4330
SN  - 1755-4349
VL  - 11
IS  - 6
SP  - 504
EP  - 509
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Dengler, Jürgen
A1  - Wagner, Viktoria
A1  - Dembicz, Iwona
A1  - Garcia-Mijangos, Itziar
A1  - Naqinezhad, Alireza
A1  - Boch, Steffen
A1  - Chiarucci, Alessandro
A1  - Conradi, Timo
A1  - Filibeck, Goffredo
A1  - Guarino, Riccardo
A1  - Janisova, Monika
A1  - Steinbauer, Manuel J.
A1  - Acic, Svetlana
A1  - Acosta, Alicia T. R.
A1  - Akasaka, Munemitsu
A1  - Allers, Marc-Andre
A1  - Apostolova, Iva
A1  - Axmanova, Irena
A1  - Bakan, Branko
A1  - Baranova, Alina
A1  - Bardy-Durchhalter, Manfred
A1  - Bartha, Sandor
A1  - Baumann, Esther
A1  - Becker, Thomas
A1  - Becker, Ute
A1  - Belonovskaya, Elena
A1  - Bengtsson, Karin
A1  - Benito Alonso, Jose Luis
A1  - Berastegi, Asun
A1  - Bergamini, Ariel
A1  - Bonini, Ilaria
A1  - Bruun, Hans Henrik
A1  - Budzhak, Vasyl
A1  - Bueno, Alvaro
A1  - Antonio Campos, Juan
A1  - Cancellieri, Laura
A1  - Carboni, Marta
A1  - Chocarro, Cristina
A1  - Conti, Luisa
A1  - Czarniecka-Wiera, Marta
A1  - De Frenne, Pieter
A1  - Deak, Balazs
A1  - Didukh, Yakiv P.
A1  - Diekmann, Martin
A1  - Dolnik, Christian
A1  - Dupre, Cecilia
A1  - Ecker, Klaus
A1  - Ermakov, Nikolai
A1  - Erschbamer, Brigitta
A1  - Escudero, Adrian
A1  - Etayo, Javier
A1  - Fajmonova, Zuzana
A1  - Felde, Vivian A.
A1  - Fernandez Calzado, Maria Rosa
A1  - Finckh, Manfred
A1  - Fotiadis, Georgios
A1  - Fracchiolla, Mariano
A1  - Ganeva, Anna
A1  - Garcia-Magro, Daniel
A1  - Gavilan, Rosario G.
A1  - Germany, Markus
A1  - Giladi, Itamar
A1  - Gillet, Francois
A1  - Giusso del Galdo, Gian Pietro
A1  - Gonzalez, Jose M.
A1  - Grytnes, John-Arvid
A1  - Hajek, Michal
A1  - Hajkova, Petra
A1  - Helm, Aveliina
A1  - Herrera, Mercedes
A1  - Hettenbergerova, Eva
A1  - Hobohm, Carsten
A1  - Huellbusch, Elisabeth M.
A1  - Ingerpuu, Nele
A1  - Jandt, Ute
A1  - Jeltsch, Florian
A1  - Jensen, Kai
A1  - Jentsch, Anke
A1  - Jeschke, Michael
A1  - Jimenez-Alfaro, Borja
A1  - Kacki, Zygmunt
A1  - Kakinuma, Kaoru
A1  - Kapfer, Jutta
A1  - Kavgaci, Ali
A1  - Kelemen, Andras
A1  - Kiehl, Kathrin
A1  - Koyama, Asuka
A1  - Koyanagi, Tomoyo F.
A1  - Kozub, Lukasz
A1  - Kuzemko, Anna
A1  - Kyrkjeeide, Magni Olsen
A1  - Landi, Sara
A1  - Langer, Nancy
A1  - Lastrucci, Lorenzo
A1  - Lazzaro, Lorenzo
A1  - Lelli, Chiara
A1  - Leps, Jan
A1  - Loebel, Swantje
A1  - Luzuriaga, Arantzazu L.
A1  - Maccherini, Simona
A1  - Magnes, Martin
A1  - Malicki, Marek
A1  - Marceno, Corrado
A1  - Mardari, Constantin
A1  - Mauchamp, Leslie
A1  - May, Felix
A1  - Michelsen, Ottar
A1  - Mesa, Joaquin Molero
A1  - Molnar, Zsolt
A1  - Moysiyenko, Ivan Y.
A1  - Nakaga, Yuko K.
A1  - Natcheva, Rayna
A1  - Noroozi, Jalil
A1  - Pakeman, Robin J.
A1  - Palpurina, Salza
A1  - Partel, Meelis
A1  - Paetsch, Ricarda
A1  - Pauli, Harald
A1  - Pedashenko, Hristo
A1  - Peet, Robert K.
A1  - Pielech, Remigiusz
A1  - Pipenbaher, Natasa
A1  - Pirini, Chrisoula
A1  - Pleskova, Zuzana
A1  - Polyakova, Mariya A.
A1  - Prentice, Honor C.
A1  - Reinecke, Jennifer
A1  - Reitalu, Triin
A1  - Pilar Rodriguez-Rojo, Maria
A1  - Rolecek, Jan
A1  - Ronkin, Vladimir
A1  - Rosati, Leonardo
A1  - Rosen, Ejvind
A1  - Ruprecht, Eszter
A1  - Rusina, Solvita
A1  - Sabovljevic, Marko
A1  - Maria Sanchez, Ana
A1  - Savchenko, Galina
A1  - Schuhmacher, Oliver
A1  - Skornik, Sonja
A1  - Sperandii, Marta Gaia
A1  - Staniaszek-Kik, Monika
A1  - Stevanovic-Dajic, Zora
A1  - Stock, Marin
A1  - Suchrow, Sigrid
A1  - Sutcliffe, Laura M. E.
A1  - Swacha, Grzegorz
A1  - Sykes, Martin
A1  - Szabo, Anna
A1  - Talebi, Amir
A1  - Tanase, Catalin
A1  - Terzi, Massimo
A1  - Tolgyesi, Csaba
A1  - Torca, Marta
A1  - Torok, Peter
A1  - Tothmeresz, Bela
A1  - Tsarevskaya, Nadezda
A1  - Tsiripidis, Ioannis
A1  - Tzonev, Rossen
A1  - Ushimaru, Atushi
A1  - Valko, Orsolya
A1  - van der Maarel, Eddy
A1  - Vanneste, Thomas
A1  - Vashenyak, Iuliia
A1  - Vassilev, Kiril
A1  - Viciani, Daniele
A1  - Villar, Luis
A1  - Virtanen, Risto
A1  - Kosic, Ivana Vitasovic
A1  - Wang, Yun
A1  - Weiser, Frank
A1  - Went, Julia
A1  - Wesche, Karsten
A1  - White, Hannah
A1  - Winkler, Manuela
A1  - Zaniewski, Piotr T.
A1  - Zhang, Hui
A1  - Ziv, Yaron
A1  - Znamenskiy, Sergey
A1  - Biurrun, Idoia
T1  - GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands
JF  - Phytocoenologia
N2  - GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board.
KW  - biodiversity
KW  - European Vegetation Archive (EVA)
KW  - Eurasian Dry Grassland Group (EDGG)
KW  - grassland vegetation
KW  - GrassPlot
KW  - macroecology
KW  - multi-taxon
KW  - nested plot
KW  - scale-dependence
KW  - species-area relationship (SAR)
KW  - sPlot
KW  - vegetation-plot database
Y1  - 2018
U6  - https://doi.org/10.1127/phyto/2018/0267
SN  - 0340-269X
VL  - 48
IS  - 3
SP  - 331
EP  - 347
PB  - Cramer
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Selsing, Jonatan
A1  - Malesani, D.
A1  - Goldoni, P.
A1  - Fynbo, Johan
A1  - Krühler, T.
A1  - Antonelli, L. A.
A1  - Arabsalmani, M.
A1  - Bolmer, J.
A1  - Cano, Z.
A1  - Christensen, L.
A1  - Covino, S.
A1  - De Cia, A.
A1  - de Ugarte Postigo, A.
A1  - Flores, H.
A1  - Fliis, M.
A1  - Gomboc, A.
A1  - Greiner, J.
A1  - Groot, P.
A1  - Hammer, F.
A1  - Hartoog, O. E.
A1  - Heintz, K. E.
A1  - Hjorth, J.
A1  - Jakobsson, P.
A1  - Japelj, J.
A1  - Kann, D. A.
A1  - Kaper, L.
A1  - Ledoux, C.
A1  - Leloudas, G.
A1  - Levan, A. J.
A1  - Maiorano, E.
A1  - Melandri, A.
A1  - Milvang-Jensen, B.
A1  - Palazzi, E.
A1  - Palmerio, J. T.
A1  - Perley, D. A.
A1  - Pian, E.
A1  - Piranomonte, S.
A1  - Pugliese, G.
A1  - Sanchez-Ramirez, R.
A1  - Savaglio, S.
A1  - Schady, P.
A1  - Schulze, S.
A1  - Sollerman, J.
A1  - Sparre, Martin
A1  - Tagliaferri, G.
A1  - Tanvir, N. R.
A1  - Thone, C. C.
A1  - Vergani, S. D.
A1  - Vreeswijk, P.
A1  - Watson, D.
A1  - Wiersema, K.
A1  - Wijers, R.
A1  - Xu, D.
A1  - Zafar, T.
T1  - The X-shooter GRB afterglow legacy sample (XS-GRB)
JF  - Astronomy and astrophysics : an international weekly journal
N2  - In this work we present spectra of all gamma-ray burst (GRB) afterglows that have been promptly observed with the X-shooter spectrograph until 31/03/2017. In total, we have obtained spectroscopic observations of 103 individual GRBs observed within 48 hours of the GRB trigger. Redshifts have been measured for 97 per cent of these, covering a redshift range from 0.059 to 7.84. Based on a set of observational selection criteria that minimise biases with regards to intrinsic properties of the GRBs, the follow-up effort has been focused on producing a homogeneously selected sample of 93 afterglow spectra for GRBs discovered by the Swift satellite. We here provide a public release of all the reduced spectra, including continuum estimates and telluric absorption corrections. For completeness, we also provide reductions for the 18 late-time observations of the underlying host galaxies. We provide an assessment of the degree of completeness with respect to the parent GRB population, in terms of the X-ray properties of the bursts in the sample and find that the sample presented here is representative of the full Swift sample. We have constrained the fraction of dark bursts to be <28 per cent and confirm previous results that higher optical darkness is correlated with increased X-ray absorption. For the 42 bursts for which it is possible, we have provided a measurement of the neutral hydrogen column density, increasing the total number of published HI column density measurements by similar to 33 per cent. This dataset provides a unique resource to study the ISM across cosmic time, from the local progenitor surroundings to the intervening Universe.
KW  - gamma-ray burst: general
KW  - galaxies: high-redshift
KW  - ISM: general
KW  - techniques: spectroscopic
KW  - catalogs
KW  - galaxies: star formation
Y1  - 2019
U6  - https://doi.org/10.1051/0004-6361/201832835
SN  - 1432-0746
SN  - 0004-6361
VL  - 623
PB  - EDP Sciences
CY  - Les Ulis
ER  -