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For refcode 1998MNRAS.296..977B:
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NED Abstract

Copyright by Royal Astronomical Society. 1998MNRAS.296..977B X-ray spectral analysis of elliptical galaxies from ASCA: the Fe abundance in a multiphase medium David A. Buote and A. C. Fabian Accepted 1998 January 12. Received 1998 January 12; in original form 1997 July 14 ABSTRACT We present spectral analysis of ASCA data of 17 elliptical and three lenticular galaxies most of which have high L_x_/L_B_. Single-temperature models (MEKAL and Raymond-Smith) give unacceptable fits (X_red_^2^ > 1.5) in most cases and, in agreement with previous studIes, give very subsolar abundances, (Z) = 0.19 +/- 0.12 Z_sun_ (MEKAL). The spectra for approximately half the sample are fitted better by a cooling-flow model, which in three cases gives a substantially better fit. The abundances derived from the cooling-flow model are also significantly larger, (Z) = 0.6 +/- 0.5 Z_sun_. We empirically tested the reliability of the plasma codes in the Fe L region and found no evidence for serious problems with the determined temperatures and abundances. Two-temperature models give substantially better fits that are formally acceptable (X_red_^2^ ~ 1.0) in all but a few cases. The highest signal-to- noise ratio galaxies (which also have highest L_x_/L_B_) have fitted temperatures <2 keV for both components consistent with each being distinct phases of hot gas. The lowest signal-to-noise ratio galaxies (which also have lowest L_x_/L_B_) generally have a hot component with temperature, T_H_ ~> 5 keV, which is consistent with emission from discrete sources. (We discuss the origin of these two components from analysis of L_X_ - L_B_ and L_x_/L_B_.) The abundances of these two-temperature models are approximately solar, (Z) = 0.9 +/- 0.7 Z_sun_(MEKAL), consistent with a recent multiphase model for the evolution of hot gas in ellipticals. Finally, for several galaxies we find evidence for absorption in excess of the Galactic value and discuss its implications. Key words: galaxies: elliptical and lenticular, CD - galaxies: evolution - galaxies: general - X-rays: galaxies.
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