SIMBAD references

2005MNRAS.358..693C - Mon. Not. R. Astron. Soc., 358, 693-704 (2005/April-1)

X-ray spectral analysis of optically faint sources in the Chandra deep fields.

CIVANO F., COMASTRI A. and BRUSA M.

Abstract (from CDS):

We present the results of a detailed spectral analysis of optically faint hard X-ray sources in the Chandra deep fields selected on the basis of their high X-ray to optical flux ratio (X/O). The stacked spectra of high X/O sources in both Chandra deep fields, fitted with a single power-law model, are much harder than the spectrum of the X-ray background (XRB). The average slope is also insensitive to the 2-8 keV flux, being approximately constant around Γ≃ 1 over more than two decades, strongly indicating that high X/O sources represent the most obscured component of the XRB. For about half of the sample, a redshift estimate (in most of the cases a photometric redshift) is available from the literature. Individual fits of a few of the brightest objects and of stacked spectra in different redshift bins imply column densities in the range 1022-1023.5/cm2. A trend of increasing absorption towards higher redshifts is suggested.

Abstract Copyright: 2005 RAS

Journal keyword(s): surveys - galaxies: active - X-rays: diffuse background - X-ray: galaxies - X-rays: general

Simbad objects: 113

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2020.02.21-11:31:12

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