IAU Symposium Abstract S186-060P


Associated X-ray emission, Ionized Gas, and Dust Extinction in NGC 5846


Paul Goudfrooij1 and Ginevra Trinchieri2,3
1 Space Telescope Science Institute, Baltimore, U.S.A. < goudfroo@stsci.edu >
2 Max-Planck-Institut f\"ur extraterrestrische Physik, Garching, Germany < ginevra@rosat.mpe-garching.mpg.de >
3 Osservatorio Astronomico di Brera, Milano, Italy



We present new optical multicolor imagery as well as ROSAT PSPC and HRI X-ray imagery of the X-ray-bright elliptical galaxy NGC 5846. A filamentary dust lane is detected in the central region of NGC 5846, with a morphology strikingly similar to that observed for the optical nebulosity {\it and\/} the X-ray emission. A physical connection between the different phases of the interstellar medium therefore seems likely. The extinction properties of the dust are entirely ``normal'', following the Galactic extinction curve. The energy deposited from the hot gas into heating of the dust grains is consistent with the temperature distribution of the X-ray-emitting gas, which is found to be lowest in the dusty regions. We argue that the dust as well as the optical nebulosity are products of a past interaction with a small, gas-rich galaxy, not remnants of a cooling flow.