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Session 83 - Elliptical Galaxies.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center
A signature in the distribution of hot gas in elliptical galaxies will be created by the inflow of material (the cooling flow) or by galaxy-galaxy interactions, so we have searched for these signatures through a careful morphological study of the X-ray emission. We examined the X-Ray emission from several bright ellipticals that are not in the centers of clusters and whose X-Ray emission is not dominated by AGN activity. These galaxies have been observed with the \itROSAT HRI, an instrument with a resolution of about 5\arcsec, whose sensitivity is much better than its predecessor on the \itEinstein observatory. A crucial part of our data analysis is the use of image simulations to quantify the morphology of these galaxies. If there are no competing effects, the X-ray gas will follow the gravitational potential of the galaxy and will allow for a calculation of the mass of the galaxy if there is corresponding kinematic data. High rotation velocities, as seen in NGC 1395 and NGC 1404, will affect the shape of the X-ray isophotes by flattening them along the axis of rotation, and we find evidence of this. Recent merger events may also disturb the structure of the ISM, but as of yet, no correlation between the morphology of the X-ray and optical isophotes in elliptical shell galaxies has been seen.
Program listing for Wednesday