Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-13553 Wissenschaftlicher Artikel Christensen, Lise Bech; Schulte-Ladbeck, R. E.; Sanchez, Sebastian F.; Becker, Thomas; Jahnke, Knud; Kelz, A.; Roth, Martin M.; Wisotzki, Lutz Abundances and kinematics of a candidate sub-damped Lymana galaxy toward PHL 1226 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 2005 Institut für Physik und Astronomie OPUS4-15763 Wissenschaftlicher Artikel Wisotzki, Lutz; Becker, Thomas; Christensen, Lise Bech; Helms, Andreas; Jahnke, Knud; Kelz, A.; Roth, Martin M.; Sanchez, Sebastian F. Integral-field spectrophotometry of the quadruple QSO HE 0435-1223 : Evidence for microlensing 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. 2003 Institut für Physik und Astronomie OPUS4-15111 Wissenschaftlicher Artikel Christensen, Lise Bech; Sanchez, Sebastian F.; Jahnke, Knud; Becker, Thomas; Wisotzki, Lutz; Kelz, A.; Popovic, L. C.; Roth, Martin M. Integral field spectroscopy of extended Ly alpha emission from the DLA galaxy in Q2233+131 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 2004 Institut für Physik und Astronomie OPUS4-15393 Wissenschaftlicher Artikel Wisotzki, Lutz; Becker, Thomas; Christensen, Lise Bech; Jahnke, Knud; Helms, Andreas; Kelz, A.; Roth, Martin M.; Sanchez, Sebastian F. Integral field spectrophotometry of gravitationally lensed QSOs with PMAS 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 2004 Institut für Physik und Astronomie OPUS4-15110 Wissenschaftlicher Artikel Christensen, Lise Bech; Sanchez, Sebastian F.; Jahnke, Knud; Becker, Thomas; Kelz, A.; Wisotzki, Lutz; Roth, Martin M. Integral field observations of damped Lyman-alpha galaxies 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" 2004 Institut für Physik und Astronomie OPUS4-15192 Wissenschaftlicher Artikel Jahnke, Knud; Wisotzki, Lutz; Sanchez, Sebastian F.; Christensen, Lise Bech; Becker, Thomas; Kelz, A.; Roth, Martin M. Integral field spectroscopy of QSO host galaxies 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 2004 Institut für Physik und Astronomie OPUS4-15764 Wissenschaftlicher Artikel Christensen, Lise Bech; Becker, Thomas; Jahnke, Knud; Kelz, A.; Roth, Martin M.; Sanchez, S. S.; Wisotzki, Lutz Integral field spectroscopy of SN 2002er with PMAS sent observations of the Type Ia supernova SN 2002er during the brightening phase. The observations were performed with the Potsdam Multi Aperture Spectrophotometer (PMAS) integral field instrument. Due to the 8arcsecx8 arcsec field of view of the spectrograph an accurate background subtraction was possible. Results from analyses of the evolution of absorption features in comparisons with other SNe show that SN 2002er is a fairly bright Type Ia supernova with a peak brightness of MB=-19.6+/-0.1. 2003 Institut für Physik und Astronomie OPUS4-13466 Wissenschaftlicher Artikel Barden, Marco; Rix, Hans-Walter; Somerville, Rachel S.; Bell, Eric F.; Häußler, Boris; Peng, Chen Y.; Borch, Andrea; Beckwith, Steven V. W.; Caldwell, John A. R.; Heymans, Catherine; Jahnke, Knud; Jogee, Shardha; McIntosh, Daniel H.; Meisenheimer, Klaus; Sanchez, Sebastian F.; Wisotzki, Lutz; Wolf, C. GEMS : the surface brightness and surface mass density evolution of disk galaxies We combine HST imaging from the GEMS ( Galaxy Evolution from Morphologies and SEDs) survey with photometric redshifts from COMBO-17 to explore the evolution of disk-dominated galaxies since z less than or similar to 1.1. The sample is composed of all GEMS galaxies with Sersic indices n < 2.5, derived from fits to the galaxy images. We account fully for selection effects through careful analysis of image simulations; we are limited by the depth of the redshift and HST data to the study of galaxies with M-V less than or similar to -20, or equivalently, log (M/M-circle dot) greater than or similar to 10. We find strong evolution in the magnitude-size scaling relation for galaxies with M-V less than or similar to -20, corresponding to a brightening of similar to 1 mag arcsec(-2) in rest-frame V band by z similar to 1. Yet disks at a given absolute magnitude are bluer and have lower stellar mass-to-light ratios at z similar to 1 than at the present day. As a result, our findings indicate weak or no evolution in the relation between stellar mass and effective disk size for galaxies with log (M/M-circle dot) greater than or similar to 10 over the same time interval. This is strongly inconsistent with the most naive theoretical expectation, in which disk size scales in proportion to the halo virial radius, which would predict that disks are a factor of 2 denser at fixed mass at z similar to 1. The lack of evolution in the stellar mass-size relation is consistent with an "inside-out'' growth of galaxy disks on average (galaxies increasing in size as they grow more massive), although we cannot rule out more complex evolutionary scenarios 2005 Institut für Physik und Astronomie OPUS4-13735 Wissenschaftlicher Artikel Kuhlbrodt, B.; Orndahl, E.; Wisotzki, Lutz; Jahnke, Knud High-redshift quasar host galaxies with adaptive optics We present K band adaptive optics observations of three high-redshift ( z similar to 2.2) high-luminosity quasars, all of which were studied for the first time. We also observed several point spread function ( PSF) calibrators, non-simultaneously because of the small field of view. The significant temporal PSF variations on timescales of minutes inhibited a straightforward scaled PSF removal from the quasar images. Characterising the degree of PSF concentration by the radii encircling 20% and 80% of the total flux, respectively, we found that even under very different observing conditions the r(20) vs. r(80) relation varied coherently between individual short exposure images, delineating a well-defined relation for point sources. Placing the quasar images on this relation, we see indications that all three objects were resolved. We designed a procedure to estimate the significance of this result, and to estimate host galaxy parameters, by reproducing the statistical distribution of the individual short exposure images. We find in all three cases evidence for a luminous host galaxy, with a mean absolute magnitude of M-R = - 27.0 and scale lengths around similar to 4 - 12 kpc. Together with a rough estimate of the central black hole masses obtained from C.. line widths, the location of the objects on the bulge luminosity vs. black hole mass relation is not significantly different from the low-redshift regime, assuming only passive evolution of the host galaxy. Corresponding Eddington luminosities are L-nuc/L-Edd similar to 0.1 - 0.6 2005 Institut für Physik und Astronomie OPUS4-15190 Wissenschaftlicher Artikel Jahnke, Knud; Kuhlbrodt, B.; Wisotzki, Lutz Quasar host galaxy star formation activity from multicolour data We investigate multicolour imaging data of a complete sample of 19 low-redshift (z < 0.2) quasar host galaxies. The sample was imaged in four optical (BVRi) and three near-infrared bands (JHK(s)). Galaxy types, structural parameters and robust host galaxy luminosities are extracted for all bands by means of two-dimensional deblending of galaxy and nucleus. For the disc-dominated fraction of host galaxies (Sa and later) the optical and optical-to-near-infrared colours agree well with the average colours of inactive galaxies of the same type. The bulge-dominated galaxies (E/S0), on the other hand, appear a significant 0.3 mag bluer in (V-K) than their inactive counterparts, being as blue as the discs in the sample. This trend is confirmed by fitting population synthesis models to the extracted broad-band spectral energy distributions: the stellar population age of the bulge-dominated hosts lies around a few Gyr, much younger than expected for old evolved ellipticals. Comparison to other studies suggests a strong trend for stellar age in elliptical host galaxies with luminosity. Intermediately luminous elliptical hosts have comparably young populations, either intrinsically or from an enhanced star formation rate potentially due to interaction; the most luminous and massive ellipticals on the contrary show old populations. The correspondence between the nuclear activity and the blue colours suggests a connection between galaxy interaction, induced star formation and the triggering of nuclear activity. However, the existence of very symmetric and undisturbed discs and elliptical host galaxies emphasized that other mechanisms like minor merging or gas accretion must exist 2004 Institut für Physik und Astronomie OPUS4-15191 Wissenschaftlicher Artikel Jahnke, Knud; Sanchez, Sebastian F.; Wisotzki, Lutz; Barden, Marco; Beckwith, Steven V. W.; Bell, Eric F.; Borch, Andrea; Caldwell, John A. R.; Häußler, Boris; Heymans, Catherine; Jogee, Shardha; McIntosh, Daniel H.; Meisenheimer, Klaus; Peng, Chen Y.; Rix, Hans-Walter; Somerville, Rachel S.; Wolf, C. Ultraviolet light from young stars in GEMS quasar host galaxies at 1.8 < z < 2.75 We have performed Hubble Space Telescope imaging of a sample of 23 high-redshift (1.8 10(9) M-circle dot) to provide only poor fit to the data. Power law models, which best fit the data, provide a total mass of M(<10 kpc) = 9.2 x 10(10) M-&ODOT;. We conclude that the recent interaction between HE 1434-1600 and its closest companion has strongly affected the gas velocity and ionization state, from the center of the galaxy to its most external parts 2004 Institut für Geowissenschaften OPUS4-15214 Wissenschaftlicher Artikel Kuhlbrodt, B.; Wisotzki, Lutz; Jahnke, Knud Decomposition of active galactic nucleus host galaxy images We describe an algorithm to decompose deep images of active galactic nuclei into host galaxy and nuclear components. Currently supported are three galaxy models: a de Vaucouleurs spheroidal; an exponential disc; and a two- component disc + bulge model. Key features of the method are: (semi-)analytic representation of a possibly spatially variable point spread function; full two-dimensional convolution of the model galaxy using gradient-controlled adaptive subpixelling; and a multiple iteration scheme. The code is computationally efficient and versatile for a wide range of applications. The quantitative performance is measured by analysing simulated imaging data. We also present examples of the application of the method to small test samples of nearby Seyfert 1 galaxies and quasars at redshifts z < 0.35 2004 Institut für Physik und Astronomie OPUS4-15313 Wissenschaftlicher Artikel Sanchez, Sebastian F.; Jahnke, Knud; Wisotzki, Lutz; McIntosh, Daniel H.; Bell, Eric F.; Barden, Marko; Beckwith, Steven V. W.; Borch, Andrea; Caldwell, John A. R.; Haussler, Boris; Jogee, Shardha; Meisenheimer, Klaus; Peng, Chen Y.; Rix, Hans-Walter; Somerville, Rachel S.; Wolf, C. Colors of active galactic nucleus host galaxies at 0.5 < z < 1.1 from the GEMS survey We present the results from a study of the host galaxies of 15 optically selected active galactic nuclei (AGNs) with 0.5