THE DISTRIBUTION OF DARK AND LUMINOUS MATTER IN ELLIPTICAL GALAXIES

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Session 52 -- Elliptical Galaxies
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

[52.18] THE DISTRIBUTION OF DARK AND LUMINOUS MATTER IN ELLIPTICAL GALAXIES

Natasha A.P. Hazell (Fordham University), Christine Jones (SAO)

Hot x-ray emitting coronae have been detected around elliptical galaxies. This project studied a sample of fourteen elliptical galaxies observed by the ROSAT PSPC. For each galaxy, we found the gas density and temperature as a function of radius from the center. We assumed that the gas in the galaxy is in hydrostatic equlibrium, and used the gas density and temperature to measure the total (dark and luminous) mass around the galaxy. Outside the central cool region, the gas is nearly isothermal with temperatures near 1 keV ($10^7 K$). For each galaxy, our measurements of the total gravitating mass give values on the order of $10^{13}~M_\odot$. The optical and gas mass were found to compose about 11\% of the total mass. The dominant mass in the galaxy halo is dark matter. Typical values for mass-to-light ratios are on the order of 75 - 100 $M_{\odot}$/ $L_{\odot}$.

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