[48.12] Tracing the Accretion History of the Universe using X-rays from the Red Galaxy Population in the Bootes Field.

AAS 204th Meeting, June 2004
Session 48 Galaxy Evolution and Galaxy Clustering in the NDWFS' Bootes Field
Topical Session, Wednesday, June 2, 2004, 8:30-10:00am, 10:45am-12:30pm, 603/605/607

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[48.12] Tracing the Accretion History of the Universe using X-rays from the Red Galaxy Population in the Bootes Field.

K. Brand, M. J. Brown, A. Dey, B. Jannuzi, J. Najita (NOAO), C. Kochanek, C. R. Watson (Ohio State University), P. Green, D. Fabricant, G. Fazio, W. Forman, C. Jones, A. Kenter, S. Murray, A. Vikhlinin, B. McNamara, J. Shields, M. Rieke (CfA)

The Chandra survey within the Bootes region of the NOAO Deep Wide-Field Survey (NDWFS) is unique in its large (9 deg²) contiguous area at relatively deep flux limits as well as the comprehensive deep multi-wavelength coverage that exists within the same region. As such, it can be used to determine the X-ray properties of well defined populations of galaxies from the NDWFS. We will present a stacking analysis of the X-rays from the red galaxy population in the NDWFS. These galaxies have well determined photometric redshifts and thus can be used to study the evolution of the average X-ray emission from this population out to redshifts of z~1. At the depths we are considering, X-rays are expected to be emitted from both AGN and ultra-luminous X-ray binaries (as well as a possible soft X-ray contribution from hot gas). We will discuss how we measure the contribution of nuclear X-ray emission and how the X-ray luminosity and thus also the acretion rate changes with redshift. Preliminary results show that the both the X-ray luminosity and the relative fraction of hard X-rays increases with redshift.

Our research is supported by the National Optical Astronomy Observatory which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the National Science Foundation. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO3-4176 issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics and Space Administration under contract NAS8-39073.

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