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Title: Early-type galaxies in the Chandra cosmos survey

We study a sample of 69 X-ray detected early-type galaxies (ETGs), selected from the Chandra COSMOS survey, to explore the relation between the X-ray luminosity of hot gaseous halos (L{sub X,{sub gas}}) and the integrated stellar luminosity (L{sub K} ) of the galaxies, in a range of redshift extending out to z = 1.5. In the local universe, a tight, steep relationship has been established between these two quantities (L{sub X,gas}∼L{sub K}{sup 4.5}), suggesting the presence of largely virialized halos in X-ray luminous systems. We use well-established relations from the study of local universe ETGs, together with the expected evolution of the X-ray emission, to subtract the contribution of low-mass X-ray binary populations from the X-ray luminosity of our sample. Our selection minimizes the presence of active galactic nuclei (AGNs), yielding a sample representative of normal passive COSMOS ETGs; therefore, the resulting luminosity should be representative of gaseous halos, although we cannot exclude other sources such as obscured AGNs or enhanced X-ray emission connected with embedded star formation in the higher-z galaxies. We find that most of the galaxies with estimated L{sub X} < 10{sup 42} erg s{sup –1} and z < 0.55 follow the L{sub X,{sub gas}}-L{sub K} relationmore » of local universe ETGs. For these galaxies, the gravitational mass can be estimated with a certain degree of confidence from the local virial relation. However, the more luminous (10{sup 42} erg s{sup –1}« less
Authors:
 [1] ; ; ; ;  [2] ;  [3] ;  [4]
  1. Yale Center for Astronomy and Astrophysics, 260 Whitney Avenue, New Haven, CT 06520 (United States)
  2. Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
  3. Universitá degli Studi di Bologna, Dipartimento di Astronomia, Via Ranzani 1, I-40127 Bologna (Italy)
  4. Great Neck South High School, 341 Lakeville Road Great Neck, NY 11020 (United States)
Publication Date:
OSTI Identifier:
22365620
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 790; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; EVOLUTION; FEEDBACK; GALAXY NUCLEI; LUMINOSITY; MASS; RED SHIFT; STARS; UNIVERSE; X RADIATION; X-RAY GALAXIES