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The Chandra Deep Field North Survey. IX. Extended X-ray Sources

F. E. Bauer·D. M. Alexander·W. N. Brandt·A. E. Hornschemeier·T. Miyaji·G. P. Garmire·D. P. Schneider·M. W. Bautz·G. Chartas·R. E. Griffiths·W. L. W. Sargent
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Abstract

The ~1 Ms Chandra Deep Field North observation is used to study the extended X-ray sources in the region surrounding the Hubble Deep Field North (HDF-N), yielding the most sensitive probe of extended X-ray emission at cosmological distances to date. A total of six such sources are detected, the majority of which align with small numbers of optically bright galaxies. Their angular sizes, band ratios, and X-ray luminosities -- assuming they lie at the same distances as the galaxies coincident with the X-ray emission -- are generally consistent with the properties found for nearby groups of galaxies. One source is notably different and is likely to be a poor-to-moderate X-ray cluster at high redshift (i.e., z > 0.7). We are also able to place strong constraints on the optically detected cluster of galaxies ClG 1236+6215 at z=0.85 and the wide-angle-tail radio galaxy VLA J123725.7+621128 at z~1-2. With rest-frame 0.5--2.0 keV X-ray luminosities of <(3-15)e42 ergs s^{-1}, the environments of both sources are either likely to have a significant deficit of hot intra-cluster gas compared to local clusters of galaxies, or they are X-ray groups. We find the surface density of extended X-ray sources in this observation to be 167 (+97,-67) deg^{-2} at a limiting soft-band flux of approximately 3e-16 ergs s^{-1} cm^{-2}. No evolution in the X-ray luminosity function of clusters is needed to explain this value. (Abridged)

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F. E. Bauer, D. M. Alexander, W. N. Brandt, A. E. Hornschemeier, T. Miyaji, G. P. Garmire, D. P. Schneider, M. W. Bautz, G. Chartas, R. E. Griffiths, W. L. W. Sargent. 2001-11-30. The Chandra Deep Field North Survey. IX. Extended X-ray Sources. https://doi.org/10.1086/338903

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