@article{WambsganssBrunnerSchindleretal.1999,
  author    = {Wambsganß, Joachim and Brunner, H. and Schindler, Sabine and Falco, E.},
  title     = {The gravitationally lensed quasar Q2237+0305 in X-rays: ROSAT/HRI detection of the "Einstein Cross"},
  year      = {1999},
  abstract  = {We report the first detection of the gravitationally lensed quasar Q2237+0305 in X-rays. With a ROSAT/HRI exposure of 53 ksec taken in Nov./Dec. 1997, we found a count rate of 0.006 counts per second for the combined four images. This corresponds to an X-ray flux of 2.2*E(-13) erg/cm(2) /sec and an X-ray luminosity of 4.2*E(45) erg/sec (in the ROSAT energy window 0.1-2.4 keV). The ROSAT/HRI detector is not able to resolve spatially the four quasar images (maximum separation 1.8 arcsec). The analysis is based on about 330 source photons. The signal is consistent with no variability, but with low significance. This detection is promising in view of the upcoming X-ray missions with higher spatial/spectral resolution and/or collecting power (Chandra X-ray Observatory, XMM and ASTRO-E).},
  language  = {en}
}
@article{WambsganssSchindler1999,
  author    = {Wambsganß, Joachim and Schindler, Sabine},
  title     = {ROSAT observations of clusters CL0500-24 \& CL0939+4713},
  year      = {1999},
  language  = {en}
}
@article{GilMerinoSchindler2003,
  author    = {Gil-Merino, Rodrigo and Schindler, Sabine},
  title     = {Galaxy and hot gas distributions in the z=0.52 galaxy cluster RBS380 from CHANDRA and NTT observations},
  year      = {2003},
  abstract  = {We present CHANDRA X-ray and NTT optical observations of the distant z=0.52 galaxy cluster RBS380 -- the most distant cluster of the ROSAT Bright Source (RBS) catalogue. We find diffuse, non-spherically symmetric X-ray emission with a X-ray luminosity of L_X(0.3-10 keV)=1.6 10^(44) erg/s, which is lower than expected from the RBS. The reason is a bright AGN in the centre of the cluster contributing considerably to the X-ray flux. This AGN could not be resolved with ROSAT. In optical wavelength we identify several galaxies belonging to the cluster. The galaxy density is at least 2 times higher than expected for such a X-ray faint cluster, which is another confirmation of the weak correlation between X-ray luminosity and optical richness. The example of the source confusion in this cluster shows how important high- resolution X-ray imaging is for cosmological research.},
  language  = {en}
}
@article{deFilippisSchindlerCastilloMoralesetal.2002,
  author    = {de Filippis, E. and Schindler, Sabine and Castillo-Morales, A. and Schwope, A. D and Wambsganß, Joachim},
  title     = {Discovery of holes in the core of the distant galaxy cluster RBS797 in a CHANDRA observation},
  isbn      = {1-583-81108-7},
  year      = {2002},
  language  = {en}
}
@article{SchindlerCastilloMoralesDeFilippisetal.2001,
  author    = {Schindler, Sabine and Castillo-Morales, A. and De Filippis, E. and Schwope, A. D. and Wambsganß, Joachim},
  title     = {Discovery of depressions in the X-ray emission of the distant galaxy cluster RBS797 in a CHANDRA observation},
  year      = {2001},
  abstract  = {We present CHANDRA observations of the X-ray luminous, distant galaxy cluster RBS797 at z=0.35. In the central region the X-ray emission shows two pronounced X-ray minima, which are located opposite to each other with respect to the cluster centre. These depressions suggest an interaction between the central radio galaxy and the intra-cluster medium, which would be the first detection in such a distant cluster. The minima are symmetric relative to the cluster centre and very deep compared to similar features found in a few other nearby clusters. A spectral and morphological analysis of the overall cluster emission shows that RBS797 is a hot cluster (T=7.7+1.2-1.0 keV) with a total mass of Mtot(r500)= 6.5+1.6-1.2 *E14Msun.},
  language  = {en}
}