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Infrared observations of serendipitous hard Chandra X-ray sources

C. S. Crawford·A. C. Fabian·P. Gandhi·R. J. Wilman·R. M. Johnstone
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Abstract

We present observations of a sample of optically-faint, hard X-ray sources of the kind likely to be responsible for much of the hard X-ray background. We confirm that such sources are easily detected in the near-infrared, and find that they have a featureless continuum suggesting that the active nucleus is heavily obscured. The infrared colours of the majority of the targets observed are consistent with absorbed elliptical host galaxies at z=1-2. It is likely that we are observing some of the brighter members of the important new class of X-ray Type II quasars.

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C. S. Crawford, A. C. Fabian, P. Gandhi, R. J. Wilman, R. M. Johnstone. 2000-05-11. Infrared observations of serendipitous hard Chandra X-ray sources. https://doi.org/10.1046/j.1365-8711.2001.04335.x

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