Detecting high redshift evolved galaxies as the hosts of optically faint hard X-ray sources

L. L. Cowie; A. J. Barger; M. W. Bautz; P. Capak; C. S. Crawford; A. C. Fabian; E. M. Hu; F. Iwamuro; J. -P. Kneib; T. Maihara; K. Motohara

doi:10.1086/319839

arXiv · astro-ph/0102306

Detecting high redshift evolved galaxies as the hosts of optically faint hard X-ray sources

L. L. Cowie·A. J. Barger·M. W. Bautz·P. Capak·C. S. Crawford·A. C. Fabian·E. M. Hu·F. Iwamuro·J. -P. Kneib·T. Maihara·K. Motohara

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Abstract

We combine deep Subaru near-infrared images of the massive lensing clusters A2390 and A370 with Keck optical data to map the spectral energy distributions (SEDs) of Chandra X-ray sources lying behind the clusters. The three sources behind A2390 are found to have extremely red colors with SEDs consistent with evolved galaxies at redshifts z>1.4. One source has extremely anomalous colors, which we interpret as evidence for a type Sa SED at a redshift around 2.5. The photometric redshift of another source has been confirmed at z=1.467 from near-infrared spectroscopy using the CISCO spectrograph on Subaru. Mapping of optically faint hard X-ray sources may prove to be an extremely efficient way to locate luminous evolved galaxies at high redshifts.

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L. L. Cowie, A. J. Barger, M. W. Bautz, P. Capak, C. S. Crawford, A. C. Fabian, E. M. Hu, F. Iwamuro, J. -P. Kneib, T. Maihara, K. Motohara. 2001-02-18. Detecting high redshift evolved galaxies as the hosts of optically faint hard X-ray sources. https://doi.org/10.1086/319839

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