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Broad band X-ray Telescope observations of the hot interstellar media in NGC 1399 and NGC 4472We present our analysis and interpretation of spatially resolved X-ray spectroscopy of the elliptical galaxies NGC 1399 and NGC 4472 obtained with the Broad Band X-Ray Telescope. The X-ray emission from both galaxies is dominated by thermal emission from a hot interstellar medium. The temperature of the plasma in NGC 1399 is 1.0-1.2 keV with a mild positive temperature gradient; for NGC 4472 the average temperature is 0.7-1.0 keV. The temperature of NGC 1399, when combined with other X-ray and optical data, implies that, if the gas is gravitationally confined, about 70 percent of the mass inside a radius of about 8.6 arcmin (38 kpc) is nonluminous. The derived metallicities and metallicity gradients are consistent with optically determined stellar metallicities, and allow surprisingly small upper limits to be placed on Type Ia supernovae rates in both galaxies. The implications of this for the gasdynamical evolution of the two galaxies are discussed. Limits on the oxygen-to-iron ratio and the line-of-sight column density are derived. There is a possible detection of cold gas in the line of sight to NGC 1399 that exceeds the Galactic value. Constraints on the contribution from a harder spectral component are placed, and likely candidates for the origin of this secondary component are evaluated.
Document ID
19930071060
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Serlemitsos, P. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Loewenstein, M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mushotzky, R. F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Marshall, F. E.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Petre, R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
August 20, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 413
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A55057
Distribution Limits
Public
Copyright
Other

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