NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-08-20 T23:27:00 PDT
Help | Comment | NED Home

For refcode 1996ApJ...470L..35D:
Retrieve 30 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
1996ApJ...470L..35D ROSAT TEMPERATURES AND ABUNDANCES FOR A COMPLETE SAMPLE OF ELLIPTICAL GALAXIES DAVID S. DAVIS AND RAYMOND E. WHITE III Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487-0324 Received 1996 April 1; accepted 1996 July 26 ABSTRACT We determine X-ray temperatures and abundances for elliptical galaxies drawn from a complete, optically selected sample. The optical magnitude- limited sample consists of 43 galaxies, complete to a (corrected) B magnitude of m_B_^0^ = 11.36. Of these, 30 have enough X-ray spectral counts to allow temperature determinations. We find that the temperatures of the X-ray-emitting gas in these elliptical galaxies are correlated with the central stellar velocity dispersions: T is proportional to {sigma}^1.45^; this is a shallower trend than the simple thermal relation T is proportional to {sigma}^2^. The diffuse gas is substantially hotter than the kinetic temperature of the luminous stars, since kT > {mu}_p_{sigma}^2^ for all galaxies with measurable temperatures. This strongly indicates that dark matter halos are characterized by velocity dispersions that exceed those of the luminous stars. We see no evidence of emission from X-ray binaries becoming progressively more dominant in lower luminosity elliptical galaxies. We find that so-called "supersoft" sources adhere to the observed kT-{sigma} relation, so they are no softer than expected for their velocity dispersions. We also find that interstellar medium temperatures and abundances are correlated, with the gas in hotter systems being more enriched than in cooler galaxies. However, no correlation is found between gaseous abundances and stellar abundances, as inferred from Mg_2_ indices. Subject headings: galaxies: abundances - galaxies: elliptical and lenticular, cD - galaxies: ISM - X-ray: galaxies
Retrieve 30 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home