@article{WisotzkiBeckerChristensenetal.2003,
  author    = {Wisotzki, Lutz and Becker, Thomas and Christensen, Lise Bech and Helms, Andreas and Jahnke, Knud and Kelz, A. and Roth, Martin M. and Sanchez, Sebastian F.},
  title     = {Integral-field spectrophotometry of the quadruple QSO HE 0435-1223 : Evidence for microlensing},
  year      = {2003},
  abstract  = {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.},
  language  = {en}
}
@article{ChristensenBeckerJahnkeetal.2003,
  author    = {Christensen, Lise Bech and Becker, Thomas and Jahnke, Knud and Kelz, A. and Roth, Martin M. and Sanchez, S. S. and Wisotzki, Lutz},
  title     = {Integral field spectroscopy of SN 2002er with PMAS},
  year      = {2003},
  abstract  = {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.},
  language  = {en}
}
@article{ChristensenSanchezJahnkeetal.2004,
  author    = {Christensen, Lise Bech and Sanchez, Sebastian F. and Jahnke, Knud and Becker, Thomas and Wisotzki, Lutz and Kelz, A. and Popovic, L. C. and Roth, Martin M.},
  title     = {Integral field spectroscopy of extended Ly alpha emission from the DLA galaxy in Q2233+131},
  year      = {2004},
  abstract  = {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},
  language  = {en}
}
@article{WisotzkiBeckerChristensenetal.2004,
  author    = {Wisotzki, Lutz and Becker, Thomas and Christensen, Lise Bech and Jahnke, Knud and Helms, Andreas and Kelz, A. and Roth, Martin M. and Sanchez, Sebastian F.},
  title     = {Integral field spectrophotometry of gravitationally lensed QSOs with PMAS},
  issn      = {0004-6337},
  year      = {2004},
  abstract  = {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},
  language  = {en}
}
@article{ChristensenSanchezJahnkeetal.2004,
  author    = {Christensen, Lise Bech and Sanchez, Sebastian F. and Jahnke, Knud and Becker, Thomas and Kelz, A. and Wisotzki, Lutz and Roth, Martin M.},
  title     = {Integral field observations of damped Lyman-alpha galaxies},
  year      = {2004},
  abstract  = {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"},
  language  = {en}
}
@article{JahnkeWisotzkiSanchezetal.2004,
  author    = {Jahnke, Knud and Wisotzki, Lutz and Sanchez, Sebastian F. and Christensen, Lise Bech and Becker, Thomas and Kelz, A. and Roth, Martin M.},
  title     = {Integral field spectroscopy of QSO host galaxies},
  year      = {2004},
  abstract  = {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},
  language  = {en}
}
@article{ChristensenSchulteLadbeckSanchezetal.2005,
  author    = {Christensen, Lise Bech and Schulte-Ladbeck, R. E. and Sanchez, Sebastian F. and Becker, Thomas and Jahnke, Knud and Kelz, A. and Roth, Martin M. and Wisotzki, Lutz},
  title     = {Abundances and kinematics of a candidate sub-damped Lymana galaxy toward PHL 1226},
  year      = {2005},
  abstract  = {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},
  language  = {en}
}