The NuSTAR Serendipitous Survey: The 40-month Catalog and the Properties of the Distant High-energy X-Ray Source Population
journal contribution
posted on 2018-08-16, 09:02 authored by G. B. Lansbury, D. Stern, J. Aird, D. M. Alexander, C. Fuentes, F. A. Harrison, E. Treister, F. E. Bauer, J. A. Tomsick, M. Baloković, A. Del Moro, P. Gandhi, M. Ajello, A. Annuar, D. R. Ballantyne, S. E. Boggs, W. N. Brandt, M. Brightman, C-T. J. Chen, F. E. Christensen, F. Civano, A. Comastri, W. W. Craig, K. Forster, B. W. Grefenstette, C. J. Hailey, R. C. Hickox, B. Jiang, H. D. Jun, M. Koss, S. Marchesi, A. D. Melo, J. R. Mullaney, G. Noirot, S. Schulze, D. J. Walton, L. Zappacosta, W. W. ZhangWe present the first full catalog and science results for the Nuclear Spectroscopic Telescope Array (NuSTAR) serendipitous survey. The catalog incorporates data taken during the first 40 months of NuSTAR operation, which provide ≈20 Ms of effective exposure time over 331 fields, with an areal coverage of 13 deg^2, and 497 sources detected in total over the 3-24 keV energy range. There are 276 sources with spectroscopic redshifts and classifications, largely resulting from our extensive campaign of ground-based spectroscopic follow-up. We characterize the overall sample in terms of the X-ray, optical, and infrared source properties. The sample is primarily composed of active galactic nuclei (AGNs), detected over a large range in redshift from z = 0.002 to 3.4 (median of =0.56), but also includes 16 spectroscopically confirmed Galactic sources. There is a large range in X-ray flux, from log(f(3-24keV)/erg s^-1 cm^-2) ≈ -14 to -11, and in rest-frame 10-40 keV luminosity, from log(L(10-40keV)/erg s^-1 cm^-2 ) ≈ 39 to 46, with a median of 44.1. Approximately 79% of the NuSTAR sources have lower-energy (<10 keV) X-ray counterparts from XMM-Newton, Chandra, and Swift XRT. The mid-infrared (MIR) analysis, using WISE all-sky survey data, shows that MIR AGN color selections miss a large fraction of the NuSTAR-selected AGN population, from ≈15% at the highest luminosities (L(X) > 10^44 erg s^-1) to ≈ 80% at the lowest luminosities (L(X) < 10^43 erg s^-1). Our optical spectroscopic analysis finds that the observed fraction of optically obscured AGNs (I.e., the type 2 fraction) is F(Type 2) =53^+14,-15 % , for a well-defined subset of the 8-24 keV selected sample. This is higher, albeit at a low significance level, than the type 2 fraction measured for redshift- and luminosity-matched AGNs selected by < 10 keV X-ray missions.
Funding
We acknowledge financial support from the Science and Technology Facilities Council (STFC) grants ST/K501979/1 (G.B.L.), ST/I001573/1 (D.M.A.), and ST/J003697/2 (P.G.); a Herchel Smith Postdoctoral Fellowship of the University of Cambridge (G.B.L.); the ERC Advanced Grant FEEDBACK 340442 at the University of Cambridge (J.A.); a COFUND Junior Research Fellowship from the Institute of Advanced Study, Durham University (J.A.); the Leverhulme Trust (D.M.A.); CONICYT-Chile grants FONDECYT 1120061 and 1160999 (E.T.), 3140534 (S.S.), and Anillo ACT1101 (E.T. and F.E.B.); the Center of Excellence in Astrophysics and Associated Technologies (PFB 06; E.T. and F.E.B.); and the NASA Earth and Space Science Fellowship Program, grant NNX14AQ07H (M.B.). We extend gratitude to Felipe Ardila, Roberto Assef, Eduardo Bañados, Stanislav George Djorgovski, Andrew Drake, Jack Gabel, Audrey Galametz, Daniel Gawerc, David Girou, Marianne Heida, Nikita Kamraj, Peter Kosec, Thomas Krühler, Ashish Mahabal, Alessandro Rettura, and Aaron Stemo for their support during the ground-based follow-up observations. We thank John Lucey for unearthing the J1410 spectrum, and Sophie Reed, David Rosario, Mara Salvato, and Martin Ward for the informative discussions. Additional thanks to Eden Stern for lending a hand during the 2015 August Keck run. This work was supported under NASA Contract No. NNG08FD60C and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). Facilities: Chandra, ESO La Silla, Gemini, Kec
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Citation
Astrophysical Journal, 2017, 836, pp. 99-99Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and AstronomyVersion
- VoR (Version of Record)
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Astrophysical JournalPublisher
American Astronomical Society, IOP Publishingissn
0004-637Xeissn
1538-4357Acceptance date
2016-12-07Copyright date
2017Available date
2018-08-16Publisher DOI
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http://iopscience.iop.org/article/10.3847/1538-4357/836/1/99/metaLanguage
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