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X-UDS: The Chandra Legacy Survey of the UKIDSS Ultra Deep Survey Field

Kocevski, Dale D. and Brightman, Murray (2018) X-UDS: The Chandra Legacy Survey of the UKIDSS Ultra Deep Survey Field. Astrophysical Journal Supplement Series, 236 (2). Art. No. 48. ISSN 1538-4365. doi:10.3847/1538-4365/aab9b4.

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We present the X-UDS survey, a set of wide and deep Chandra observations of the Subaru-XMM Deep/UKIDSS Ultra Deep Survey (SXDS/UDS) field. The survey consists of 25 observations that cover a total area of 0.33 deg^2. The observations are combined to provide a nominal depth of ~600 ks in the central 100 arcmin^2 region of the field that has been imaged with Hubble/WFC3 by the CANDELS survey and ~200 ks in the remainder of the field. In this paper, we outline the survey's scientific goals, describe our observing strategy, and detail our data reduction and point source detection algorithms. Our analysis has resulted in a total of 868 band-merged point sources detected with a false-positive Poisson probability of <1 × 10^(−4). In addition, we present the results of an X-ray spectral analysis and provide best-fitting neutral hydrogen column densities, N_H, as well as a sample of 51 Compton-thick active galactic nucleus candidates. Using this sample, we find the intrinsic Compton-thick fraction to be 30%–35% over a wide range in redshift (z = 0.1–3), suggesting the obscured fraction does not evolve very strongly with epoch. However, if we assume that the Compton-thick fraction is dependent on luminosity, as is seen for Compton-thin sources, then our results are consistent with a rise in the obscured fraction out to z ~ 3. Finally, an examination of the host morphologies of our Compton-thick candidates shows a high fraction of morphological disturbances, in agreement with our previous results. All data products described in this paper are made available via a public website.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Brightman, Murray0000-0002-8147-2602
Additional Information:© 2018 The American Astronomical Society. Received 2017 July 17; revised 2018 January 25; accepted 2018 January 29; published 2018 June 14. We acknowledge the financial support from NASA Chandra grant GO5-16150B (D.D.K., G.H.). T.M. is supported by UNAM-DGAPA PAPIIT IN104216 and CONACyT 252531. M.B. acknowledges support from the FP7 Career Integration Grant "eEASy" (CIG 321913).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Universidad Nacional Autónoma de México (UNAM)IN104216
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)252531
European Research Council (ERC)321913 eEasy
Subject Keywords:galaxies: active – galaxies: nuclei – surveys – X-rays: galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:20180706-135358776
Persistent URL:
Official Citation:Dale D. Kocevski et al 2018 ApJS 236 48
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87607
Deposited By: Tony Diaz
Deposited On:06 Jul 2018 21:04
Last Modified:15 Nov 2021 20:49

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