The NuSTAR Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

L. Zappacosta; A. Comastri; F. Civano; S. Puccetti; F. Fiore; J. Aird; A. Del Moro; G. B. Lansbury; G. Lanzuisi; A. Goulding; J. R. Mullaney; D. Stern; M. Ajello; D. M. Alexander; D. R. Ballantyne; F. E. Bauer; W. N. Brandt; C. T.J. Chen; D. Farrah; F. A. Harrison; P. Gandhi; L. Lanz; A. Masini; S. Marchesi; C. Ricci; E. Treister

doi:10.3847/1538-4357/aaa550

The NuSTAR Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

L. Zappacosta, A. Comastri, F. Civano, S. Puccetti, F. Fiore, J. Aird, A. Del Moro, G. B. Lansbury, G. Lanzuisi, A. Goulding, J. R. Mullaney, D. Stern, M. Ajello, D. M. Alexander, D. R. Ballantyne, F. E. Bauer, W. N. Brandt, C. T.J. Chen, D. Farrah, F. A. HarrisonP. Gandhi, L. Lanz, A. Masini, S. Marchesi, C. Ricci, E. Treister

Astrophysical Sciences

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Abstract

We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting fluxof S (8-24 keV) = 7×10^-14 erg s^-1 cm^-1 in the multi-tiered NuSTAR extragalactic survey program. The sourcesspan a redshift range z = 0-2.1 (median 〈z〈 = 0.58). The spectral analysis is performed over the broad 0.5-24 keVenergy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical andphysically motivated models. This constitutes the largest sample of AGN selected at >10 keV to behomogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters suchas photon index, column density (NH), reflection parameter (R), and 10-40 keV luminosity (LX). Heavily obscured(log NH cm 23[ -2]) and Compton-thick (CT; log N cm 24 H[ -2]) AGN constitute ∼25% (15-17 sources) and∼2-3% (1-2 sources) of the sample, respectively. The observed NH distribution agrees fairly well with predictionsof cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGNas a function of NH, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CTAGN relative to log NH cm 20 24[ -2] = - AGN is poorly constrained, formally in the range 2-56% (90% upperlimit of 66%). We derived a fraction ( fabs) of obscured AGN (log NH cm 22 24[-2] = -) as a function of LX inagreement with CXBPSM and previous z < 1 X-ray determinations. Furthermore, fabs at z = 0.1-0.5 andlog Lx erg s 43.6 44.3( -1) - agrees with observational measurements/trends obtained over larger redshiftintervals. We report a significant anti-correlation of R with LX (confirmed by our companion paper on stackedspectra) with considerable scatter around the median R values.

Original language	English (US)
Article number	33
Journal	Astrophysical Journal
Volume	854
Issue number	1
DOIs	https://doi.org/10.3847/1538-4357/aaa550
State	Published - Feb 10 2018

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

galaxies: active
surveys
X-rays: galaxies

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10.3847/1538-4357/aaa550

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Zappacosta, L., Comastri, A., Civano, F., Puccetti, S., Fiore, F., Aird, J., Moro, A. D., Lansbury, G. B., Lanzuisi, G., Goulding, A., Mullaney, J. R., Stern, D., Ajello, M., Alexander, D. M., Ballantyne, D. R., Bauer, F. E., Brandt, W. N., Chen, C. T. J., Farrah, D., ... Treister, E. (2018). The NuSTAR Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample. Astrophysical Journal, 854(1), Article 33. https://doi.org/10.3847/1538-4357/aaa550

@article{6f576b5a767840f481ed32ea494ca1a4,

title = "The NuSTAR Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample",

abstract = "We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting fluxof S (8-24 keV) = 7×10-14 erg s-1 cm-1 in the multi-tiered NuSTAR extragalactic survey program. The sourcesspan a redshift range z = 0-2.1 (median 〈z〈 = 0.58). The spectral analysis is performed over the broad 0.5-24 keVenergy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical andphysically motivated models. This constitutes the largest sample of AGN selected at >10 keV to behomogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters suchas photon index, column density (NH), reflection parameter (R), and 10-40 keV luminosity (LX). Heavily obscured(log NH cm 23[ -2]) and Compton-thick (CT; log N cm 24 H[ -2]) AGN constitute ∼25% (15-17 sources) and∼2-3% (1-2 sources) of the sample, respectively. The observed NH distribution agrees fairly well with predictionsof cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGNas a function of NH, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CTAGN relative to log NH cm 20 24[ -2] = - AGN is poorly constrained, formally in the range 2-56% (90% upperlimit of 66%). We derived a fraction ( fabs) of obscured AGN (log NH cm 22 24[-2] = -) as a function of LX inagreement with CXBPSM and previous z < 1 X-ray determinations. Furthermore, fabs at z = 0.1-0.5 andlog Lx erg s 43.6 44.3( -1) - agrees with observational measurements/trends obtained over larger redshiftintervals. We report a significant anti-correlation of R with LX (confirmed by our companion paper on stackedspectra) with considerable scatter around the median R values.",

keywords = "galaxies: active, surveys, X-rays: galaxies",

author = "L. Zappacosta and A. Comastri and F. Civano and S. Puccetti and F. Fiore and J. Aird and Moro, {A. Del} and Lansbury, {G. B.} and G. Lanzuisi and A. Goulding and Mullaney, {J. R.} and D. Stern and M. Ajello and Alexander, {D. M.} and Ballantyne, {D. R.} and Bauer, {F. E.} and Brandt, {W. N.} and Chen, {C. T.J.} and D. Farrah and Harrison, {F. A.} and P. Gandhi and L. Lanz and A. Masini and S. Marchesi and C. Ricci and E. Treister",

year = "2018",

month = feb,

day = "10",

doi = "10.3847/1538-4357/aaa550",

language = "English (US)",

volume = "854",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

}

Zappacosta, L, Comastri, A, Civano, F, Puccetti, S, Fiore, F, Aird, J, Moro, AD, Lansbury, GB, Lanzuisi, G, Goulding, A, Mullaney, JR, Stern, D, Ajello, M, Alexander, DM, Ballantyne, DR, Bauer, FE, Brandt, WN, Chen, CTJ, Farrah, D, Harrison, FA, Gandhi, P, Lanz, L, Masini, A, Marchesi, S, Ricci, C & Treister, E 2018, 'The NuSTAR Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample', Astrophysical Journal, vol. 854, no. 1, 33. https://doi.org/10.3847/1538-4357/aaa550

TY - JOUR

T1 - The NuSTAR Extragalactic Surveys

T2 - X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

AU - Zappacosta, L.

AU - Comastri, A.

AU - Civano, F.

AU - Puccetti, S.

AU - Fiore, F.

AU - Aird, J.

AU - Moro, A. Del

AU - Lansbury, G. B.

AU - Lanzuisi, G.

AU - Goulding, A.

AU - Mullaney, J. R.

AU - Stern, D.

AU - Ajello, M.

AU - Alexander, D. M.

AU - Ballantyne, D. R.

AU - Bauer, F. E.

AU - Brandt, W. N.

AU - Chen, C. T.J.

AU - Farrah, D.

AU - Harrison, F. A.

AU - Gandhi, P.

AU - Lanz, L.

AU - Masini, A.

AU - Marchesi, S.

AU - Ricci, C.

AU - Treister, E.

PY - 2018/2/10

Y1 - 2018/2/10

N2 - We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting fluxof S (8-24 keV) = 7×10-14 erg s-1 cm-1 in the multi-tiered NuSTAR extragalactic survey program. The sourcesspan a redshift range z = 0-2.1 (median 〈z〈 = 0.58). The spectral analysis is performed over the broad 0.5-24 keVenergy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical andphysically motivated models. This constitutes the largest sample of AGN selected at >10 keV to behomogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters suchas photon index, column density (NH), reflection parameter (R), and 10-40 keV luminosity (LX). Heavily obscured(log NH cm 23[ -2]) and Compton-thick (CT; log N cm 24 H[ -2]) AGN constitute ∼25% (15-17 sources) and∼2-3% (1-2 sources) of the sample, respectively. The observed NH distribution agrees fairly well with predictionsof cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGNas a function of NH, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CTAGN relative to log NH cm 20 24[ -2] = - AGN is poorly constrained, formally in the range 2-56% (90% upperlimit of 66%). We derived a fraction ( fabs) of obscured AGN (log NH cm 22 24[-2] = -) as a function of LX inagreement with CXBPSM and previous z < 1 X-ray determinations. Furthermore, fabs at z = 0.1-0.5 andlog Lx erg s 43.6 44.3( -1) - agrees with observational measurements/trends obtained over larger redshiftintervals. We report a significant anti-correlation of R with LX (confirmed by our companion paper on stackedspectra) with considerable scatter around the median R values.

AB - We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting fluxof S (8-24 keV) = 7×10-14 erg s-1 cm-1 in the multi-tiered NuSTAR extragalactic survey program. The sourcesspan a redshift range z = 0-2.1 (median 〈z〈 = 0.58). The spectral analysis is performed over the broad 0.5-24 keVenergy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical andphysically motivated models. This constitutes the largest sample of AGN selected at >10 keV to behomogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters suchas photon index, column density (NH), reflection parameter (R), and 10-40 keV luminosity (LX). Heavily obscured(log NH cm 23[ -2]) and Compton-thick (CT; log N cm 24 H[ -2]) AGN constitute ∼25% (15-17 sources) and∼2-3% (1-2 sources) of the sample, respectively. The observed NH distribution agrees fairly well with predictionsof cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGNas a function of NH, accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CTAGN relative to log NH cm 20 24[ -2] = - AGN is poorly constrained, formally in the range 2-56% (90% upperlimit of 66%). We derived a fraction ( fabs) of obscured AGN (log NH cm 22 24[-2] = -) as a function of LX inagreement with CXBPSM and previous z < 1 X-ray determinations. Furthermore, fabs at z = 0.1-0.5 andlog Lx erg s 43.6 44.3( -1) - agrees with observational measurements/trends obtained over larger redshiftintervals. We report a significant anti-correlation of R with LX (confirmed by our companion paper on stackedspectra) with considerable scatter around the median R values.

KW - galaxies: active

KW - surveys

KW - X-rays: galaxies

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UR - http://www.scopus.com/inward/citedby.url?scp=85042452322&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aaa550

DO - 10.3847/1538-4357/aaa550

M3 - Article

AN - SCOPUS:85042452322

SN - 0004-637X

VL - 854

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 33

ER -

The NuSTAR Extragalactic Surveys: X-Ray Spectroscopic Analysis of the Bright Hard-band Selected Sample

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