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HST Imaging in the Chandra Deep Field South: I. Multiple AGN Populations

E. J. Schreier·A. M. Koekemoer·N. A. Grogin·R. Giacconi·R. Gilli·L. Kewley·C. Norman·G. Hasinger·P. Rosati·A. Marconi·M. Salvati·P. Tozzi
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Abstract

We present preliminary results from imaging three HST/WFPC2 fields in V and I within the Chandra Deep Field South (CDFS). HST's sensitivity and resolution are sufficient to reveal optical counterparts for 24 of the 26 CDFS X-ray sources detected in the 300 ksec X-ray catalog and to determine the morphologies of most of these. We find that the X-ray sources comprise two apparently distinct populations of optical candidates: one optically faint (I > 24) with V - I colors consistent with the I > 24 field population; the other significantly brighter (I < 22) with colors redder than the I < 22 field population. More than 2/3 of the X-ray source counterparts are resolved galaxies. The brighter sources are mostly AGN, based on their high X-ray luminosity. The optically resolved sources in the brighter population have a very narrow range of V - I color and appear to be a mix of both late and early type morphologies at low to moderate redshift. We show that the second population, with fainter optical counterparts, can be explained as higher redshift Type 2 AGN.

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E. J. Schreier, A. M. Koekemoer, N. A. Grogin, R. Giacconi, R. Gilli, L. Kewley, C. Norman, G. Hasinger, P. Rosati, A. Marconi, M. Salvati, P. Tozzi. 2001-05-16. HST Imaging in the Chandra Deep Field South: I. Multiple AGN Populations. https://arxiv.org/abs/astro-ph/0105271

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