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The NuSTAR Extragalactic Surveys: The Number Counts Of Active Galactic Nuclei And The Resolved Fraction Of The Cosmic X-ray BackgroundWe present the 3-8 kiloelectronvolts and 8-24 kiloelectronvolts number counts of active galactic nuclei (AGNs) identified in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic surveys. NuSTAR has now resolved 33 percent -39 percent of the X-ray background in the 8-24 kiloelectronvolts band, directly identifying AGNs with obscuring columns up to approximately 10 (exp 25) per square centimeter. In the softer 3-8 kiloelectronvolts band the number counts are in general agreement with those measured by XMM-Newton and Chandra over the flux range 5 times 10 (exp -15) less than or approximately equal to S (3-8 kiloelectronvolts) divided by ergs per second per square centimeter less than or approximately equal to 10 (exp -12) probed by NuSTAR. In the hard 8-24 kiloelectronvolts band NuSTAR probes fluxes over the range 2 times 10 (exp -14) less than or approximately equal to S (8-24 kiloelectronvolts) divided by ergs per second per square centimeter less than or approximately equal to 10 (exp -12), a factor approximately 100 times fainter than previous measurements. The 8-24 kiloelectronvolts number counts match predictions from AGN population synthesis models, directly confirming the existence of a population of obscured and/or hard X-ray sources inferred from the shape of the integrated cosmic X-ray background. The measured NuSTAR counts lie significantly above simple extrapolation with a Euclidian slope to low flux of the Swift/BAT15-55 kiloelectronvolts number counts measured at higher fluxes (S (15-55 kiloelectronvolts) less than or approximately equal to 10 (exp -11) ergs per second per square centimeter), reflecting the evolution of the AGN population between the Swift/BAT local (redshift is less than 0.1) sample and NuSTAR's redshift approximately equal to 1 sample. CXB (Cosmic X-ray Background) synthesis models, which account for AGN evolution, lie above the Swift/BAT measurements, suggesting that they do not fully capture the evolution of obscured AGNs at low redshifts
Document ID
20170009895
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Harrison, F. A.
(California Inst. of Tech. Pasadena, CA, United States)
Aird, J.
(Cambridge Univ. Cambridge, United Kingdom)
Civano, F.
(Yale Univ. New Haven, CT, United States)
Lansbury, G.
(Durham Univ. United Kingdom)
Mullaney, J. R.
(Sheffield Univ. United Kingdom)
Ballentyne, D. R.
(Georgia Inst. of Tech. Atlanta, GA, United States)
Alexander, D. M.
(Durham Univ. United Kingdom)
Stern, D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Ajello, M.
(Clemson Univ. SC, United States)
Barret, D.
(Toulouse Univ. France)
Bauer, F. E.
(Pontificia Univ. Catolica de Chile Santiago, Chile)
Balokovic, M.
(California Inst. of Tech. Pasadena, CA, United States)
Brandt, W. N.
(Pennsylvania State Univ. University Park, PA, United States)
Brightman, M.
(California Inst. of Tech. Pasadena, CA, United States)
Boggs, S. E.
(California Univ. Berkeley, CA, United States)
Christensen, F. E.
(Technical Univ. of Denmark Lyngby, Denmark)
Comastri, A.
(Osservatorio Astronomico Bologna, Italy)
Craig, W. W.
(California Univ. Berkeley, CA, United States)
Del Moro, A.
(Durham Univ. United Kingdom)
Forster, K.
(California Inst. of Tech. Pasadena, CA, United States)
Gandhi, P.
(Southampton Univ. United Kingdom)
Giommi, P.
(ASI Science Data Center Rome, Italy)
Grefenstette, B. W.
(California Inst. of Tech. Pasadena, CA, United States)
Hailey, C. J.
(Columbia Univ. New York, NY, United States)
Hickox, R. C.
(Dartmouth Coll. Hanover, NH, United States)
Hornstrup, A.
(Technical Univ. of Denmark Lyngby, Denmark)
Kitaguchi, T.
(Hiroshima Univ. Japan)
Koglin, J.
(Kavli Inst. for Particle Astrophysics and Cosmology Menlo Park, CA, United States)
Luo, B.
(Pennsylvania State Univ. University Park, PA, United States)
Madsen, K. K.
(California Inst. of Tech. Pasadena, CA, United States)
Mao, P. H.
(California Inst. of Tech. Pasadena, CA, United States)
Miyasaka, H.
(California Inst. of Tech. Pasadena, CA, United States)
Mori, K.
(Columbia Univ. New York, NY, United States)
Perri, M.
(ASI Science Data Center Rome, Italy)
Pivovaroff, M.
(Lawrence Livermore National Lab. Livermore, CA, United States)
Puccetti, S.
(ASI Science Data Center Rome, Italy)
Rana, V.
(California Inst. of Tech. Pasadena, CA, United States)
Treister, E.
(Universidad de Concepcion Chile)
Walton, D.
(California Inst. of Tech. Pasadena, CA, United States)
Westergaard, N. J.
(Technical Univ. of Denmark Lyngby, Denmark)
Wik, D.
(Johns Hopkins Univ. Laurel, MD, United States)
Zappacosta, L.
(Osservatorio Astronomico Rome, Italy)
Zhang, W. W.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Zoglauer, A.
(California Univ. Berkeley, CA, United States)
Date Acquired
October 11, 2017
Publication Date
November 7, 2016
Publication Information
Publication: The Astrophysical Journal
Publisher: The American Astronomical Society
Volume: 831
Issue: 2
ISSN: 2041-8205
e-ISSN: 2041-8213
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN47067
Funding Number(s)
CONTRACT_GRANT: NNG08FD60C
Distribution Limits
Public
Copyright
Other
Keywords
nucle
galaxies
active

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