Very High Redshift X-Ray–selected Active Galactic Nuclei in the Chandra Deep Field–North
Open Access
- 20 February 2003
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 584 (2) , L61-L64
- https://doi.org/10.1086/368407
Abstract
Deep Chandra X-ray exposures provide an efficient route for locating optically faint active galactic nuclei (AGN) at high redshifts. We use deep multicolor optical data to search for z>5 AGN in the 2 Ms X-ray exposure of the Chandra Deep Field-North. Of the 423 X-ray sources bright enough (z'6. The z>5 object is spectroscopically confirmed at z=5.19. Only 31 of the 77 sources with z'>25.2 are undetected in the B or V bands at the 2-sigma level and could lie at z>5. There are too few moderate luminosity AGN at z=5-6.5 to ionize the intergalactic medium.Comment: 5 pages, accepted by The Astrophysical Journal LetterKeywords
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