Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-Ray Spectral Analysis of Elliptical Galaxies from ASCA: the Fe
  Abundance in a Multi-Phase Medium   We present spectral analysis of ASCA data of 17 elliptical and 3 lenticular
galaxies most of which have high L_x/L_B. Single-temperature models (MEKAL and
Raymond-Smith) give unacceptable fits (chi^2_red > 1.5) in most cases and, in
agreement with previous studies, give very sub-solar abundances, <Z> = 0.19 +/-
0.12 Z_sun (MEKAL). The spectra for approximately half the sample are better
fit with 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 (chi^2_red ~ 1.0) in all but a few cases. The highest S/N 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
S/N 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
multi-phase 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.

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The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-th