Stellar contributions to the hard X-ray galactic ridge

Journal Article · Fri Apr 15 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160906· OSTI ID:5961049

Worrall, D M; Marshall, F E

We compare the number density of serendipitous sources in galactic plane Einstein Observatory IPC fields with predictions based on the intensity of the HEAO 1 A-2 unresolved hard X-ray galactic ridge emission. We conclude that theoretically predicted X-ray source populations of luminosity (8 x 10/sup 32/)--(3 x 10/sup 34/) ergs s/sup -1/ have 2--10 keV local surface densities of less than approx.8 x 10/sup -4/ L/sup -1//sub 32/ pc/sup -2/ and are unlikely to be the dominant contributors to the hard X-ray ridge. A new estimate for Be/neutron star binary systems, such as X Persei, which are in this luminosity range and were previously thought to be potentially large X-ray ridge contributors, gives a 2--10 keV local surface density of approx.2.6 x 10/sup -5/ L/sup -1//sub 32/ pc/sup -2/. Stellar systems of low luminosity, <4 x 10/sup 32/ ergs s/sup -1/, are more likely contributors. We find that RS CVn and cataclysmic variable systems contribute 43% +- 18% of the ridge. This predicts that a more sensitive measurement of the ridge's hard X-ray spectrum should reveal Fe-line emission. We speculate that dM stars are further major contributors.

• Research Organization: Center for Astrophysics and Space Sciences, University of California, San Diego
• OSTI ID: 5961049
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 267:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics &amp; Cosmology-- Quasi-Stellar
Radio
&amp; X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BINARY STARS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DWARF STARS
LUMINOSITY
NEUTRON STARS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SPECTRA
STARS
VARIABLE STARS
X-RAY SPECTRA