ROSAT Observations of Compact Groups of Galaxies
Abstract
A search for X-ray emission from compact groups revealed detection from 8 out of the 12 HCG images extracted from the ROSAT public archive. For two of them the X-ray emission originates from galaxies in the group. On the contrary, three groups show an extended emission clearly caused by hot intracluster gas. A Raymond-Smith hot plasma model provides an excellent fit to the X-ray spectra. The estimated temperatures are distributed in a quite narrow range (from 0.73 to 0.92 keV) and are consistent, within the errors, with 0.9 keV. The luminosity ranging from 0.75 to erg s. The most relevant result is the low metal abundance surely detected in two of them and likely in a third that characterizes the hot gas cloud responsible for the X-ray emission. The data concerning the remaining 3 detected compact groups are not sufficient to discriminate with certainty between diffuse and/or point-like X-ray emission. However the results of the spectral analysis point to the presence of a hot gas again with low metal abundance.
Cite
@article{arxiv.astro-ph/9412040,
title = {ROSAT Observations of Compact Groups of Galaxies},
author = {P. Saracco and P. Ciliegi},
journal= {arXiv preprint arXiv:astro-ph/9412040},
year = {2008}
}
Comments
uuncoded PostScript file (27 pages). Hard copy figures will be sent upon request ([email protected])