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| Title: |
|
Structure of the X-Ray--emitting Gas in the Hydra A Cluster of Galaxies |
| Authors: |
|
Ikebe, Y.; Makishima, K.; Ezawa, H.; Fukazawa, Y.; Hirayama, M.; Honda, H.; Ishisaki, Y.; Kikuchi, K.; Kubo, H.; Murakami, T.; Ohashi, T.; Takahashi, T.; Yamashita, K. |
| Journal: |
|
Astrophysical Journal v.481, p.660 |
| ../publication Date: |
|
05/1997 |
| Origin: |
|
APJ |
| ApJ Keywords: |
|
GALAXIES: CLUSTERS: INDIVIDUAL NAME: HYDRA A, GALAXIES: INTERGALACTIC MEDIUM, X-RAYS: GALAXIES |
| Abstract Copyright: |
|
(c) 1997: The American Astronomical Society |
| Bibliographic Code: |
|
1997ApJ...481..660I |
Abstract
The temperature and abundance structure in the intracluster medium (ICM)
of the Hydra A Cluster of galaxies is studied with ASCA and ROSAT. The
effect of the large extended outskirts in the point-spread function of
the X-ray telescope on ASCA is included in this analysis. In the X-ray
brightness profile, the strong central excess above a single beta model,
identified in the Einstein and ROSAT data, is also found in the harder
energy band (>4 keV). A simultaneous fit of five annular spectra
taken with the GIS instrument shows a radial distribution of the
temperature and metal abundance. A significant central enhancement in
the abundance distribution is found, while the temperature profile
suggests that the ICM is approximately isothermal, with a temperature of
~3.5 keV. The ROSAT position-sensitive proportional counter (PSPC)
spectrum in the central 1.'5 region indicates a significantly lower
temperature than the GIS result. A joint analysis of the GIS and PSPC
data reveals that the spectra can be described by a two-temperature
model as well as by a cooling flow model. In both cases, the hot-phase
gas with a temperature of ~3.5 keV occupies more than 90% of the total
emission measure within 1.'5 from the cluster center. The estimated mass
of the cooler (0.5--0.7 keV) component is ~(2--6) x 109 M&sun;, which is
comparable to the mass of hot halos seen in non-cD ellipticals. The
cooling flow model gives the mass deposition rate of 60 +/- 30 M&sun;
yr-1, an order of magnitude lower than the previous estimation.
|
