TheChandraXBootes Survey. III. Optical and Near‐Infrared Counterparts
- 10 April 2006
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 641 (1), 140-157
- https://doi.org/10.1086/500312
Abstract
The XBoötes Survey is a 5 ks Chandra survey of the Boötes Field of the NOAO Deep Wide-Field Survey (NDWFS). This survey is unique in that it is the largest (9.3 deg2) contiguous region imaged in X-ray with complementary deep optical and near-infrared (near-IR) observations. We present a catalog of the optical counterparts to the 3213 X-ray point sources detected in the XBoötes survey. Using a Bayesian identification scheme, we successfully identified optical counterparts for 98% of the X-ray point sources. The optical colors suggest that the optically detected galaxies are a combination of z < 1 massive early-type galaxies and bluer star-forming galaxies whose optical AGN emission is faint or obscured, whereas the majority of the optically detected point sources are likely quasars over a large redshift range. Our large-area, X-ray-bright, optically deep survey enables us to select a large subsample of sources (773) with high X-ray-to-optical flux ratios (fX/fo > 10). These objects are likely high-redshift and/or dust-obscured AGNs. These sources have generally harder X-ray spectra than sources with 0.1 < fX/fo < 10. Of the 73 X-ray sources with no optical counterpart in the NDWFS catalog, 47 are truly optically blank down to R ~ 25.5 (the average 50% completeness limit of the NDWFS R-band catalogs). These sources are also likely to be high-redshift and/or dust-obscured AGNs.Keywords
This publication has 53 references indexed in Scilit:
- Tracing the Nuclear Accretion History of the Red Galaxy PopulationThe Astrophysical Journal, 2005
- The Fall of Active Galactic Nuclei and the Rise of Star-forming Galaxies: A Close Look at the Chandra Deep Field X-Ray Number CountsThe Astronomical Journal, 2004
- Red Galaxy Clustering in the NOAO Deep Wide‐Field SurveyThe Astrophysical Journal, 2003
- The Chandra Deep Field North Survey. XIII. 2 Ms Point-Source CatalogsThe Astronomical Journal, 2003
- Optical and Infrared Properties of the 2 Ms Chandra Deep Field North X-Ray SourcesThe Astronomical Journal, 2003
- Deep Westerbork 1.4 GH[CLC]z[/CLC] Imaging of the Bootes FieldThe Astronomical Journal, 2002
- The HELLAS2XMM Survey. I. The X‐Ray Data and the log N–log SRelationThe Astrophysical Journal, 2002
- The Chandra Deep Field North Survey. V. 1 M[CLC]s[/CLC] Source CatalogsThe Astronomical Journal, 2001
- SExtractor: Software for source extractionAstronomy and Astrophysics Supplement Series, 1996
- The FIRST Survey: Faint Images of the Radio Sky at Twenty CentimetersThe Astrophysical Journal, 1995