The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population

D. M. Alexander; D. Stern; A. Del Moro; G. B. Lansbury; R. J. Assef; J. Aird; M. Ajello; D. R. Ballantyne; F. E. Bauer; S. E. Boggs; W. N. Brandt; Finn Erland Christensen; F. Civano; A. Comastri; W. W. Craig; M. Elvis; B. W. Grefenstette; C. J. Hailey; F. A. Harrison; R. C. Hickox; B. Luo; K. K. Madsen; J. R. Mullaney; M. Perri; S. Puccetti; C. Saez; E. Treister; C. M. Urry; W. W. Zhang; C. R. Bridge; P. R. M. Eisenhardt; A. H. Gonzalez; S. H. Miller; C. W. Tsai

doi:10.1088/0004-637X/773/2/125

The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population

D. M. Alexander, D. Stern, A. Del Moro, G. B. Lansbury, R. J. Assef, J. Aird, M. Ajello, D. R. Ballantyne, F. E. Bauer, S. E. Boggs, W. N. Brandt, Finn Erland Christensen, F. Civano, A. Comastri, W. W. Craig, M. Elvis, B. W. Grefenstette, C. J. Hailey, F. A. Harrison, R. C. HickoxB. Luo, K. K. Madsen, J. R. Mullaney, M. Perri, S. Puccetti, C. Saez, E. Treister, C. M. Urry, W. W. Zhang, C. R. Bridge, P. R. M. Eisenhardt, A. H. Gonzalez, S. H. Miller, C. W. Tsai

Research output: Contribution to journal › Journal article › Research › peer-review

340 Downloads (Pure)

Abstract

We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array ( NuSTAR ) to provide the first sensitive census of the cosmic X-ray background source population at ≳ 10 keV. We find that these NuSTAR -detected sources are ≈ 100 times fainter than those previously detected at ≳ 10 keV and have a broad range in redshift and luminosity ( z = 0.020-2.923 and L10-40 keV ≈ 4 × 1041 -5 × 1045 erg s-1); the median redshift and luminosity are z ≈ 0.7 and L 10-40 keV ≈ 3 × 1044 erg s-1, respectively. We characterize these sources on the basis of broad-band ≈ 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L10-40 keV > 1044 erg s-1, of which ≈ 50% are obscured with NH ≳ 1022 cm-2. However, none of the 10 NuSTAR sources are Compton thick (NH ≳ 1024 cm-2) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L10-40 keV > 1044 erg s-1) selected at ≳ 10 keV of ≲ 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame ≈ 10-40 keV data for all of the non-beamed sources with L10-40 keV > 1043 erg s-1 to constrain the average strength of reflection; we find R <1.4 for Γ = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at ≳ 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of ≈ 1011 M⊙, a factor ≈ 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

Original language	English
Article number	125
Journal	Astrophysical Journal
Volume	773
Issue number	2
Number of pages	20
ISSN	0004-637X
DOIs	https://doi.org/10.1088/0004-637X/773/2/125
Publication status	Published - 2013

Access to Document

10.1088/0004-637X/773/2/125

0004-637X_773_2_125Final published version, 1.2 MB

http://iopscience.iop.org.globalproxy.cvt.dk/0004-637X/773/2/125/

OpenUrl availability

Full text

Cite this

Alexander, D. M., Stern, D., Del Moro, A., Lansbury, G. B., Assef, R. J., Aird, J., Ajello, M., Ballantyne, D. R., Bauer, F. E., Boggs, S. E., Brandt, W. N., Christensen, F. E., Civano, F., Comastri, A., Craig, W. W., Elvis, M., Grefenstette, B. W., Hailey, C. J., Harrison, F. A., ... Tsai, C. W. (2013). The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population. Astrophysical Journal, 773(2), Article 125. https://doi.org/10.1088/0004-637X/773/2/125

@article{d686859f95794616853b786bfc793b82,

title = "The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population",

abstract = "We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array ( NuSTAR ) to provide the first sensitive census of the cosmic X-ray background source population at ≳ 10 keV. We find that these NuSTAR -detected sources are ≈ 100 times fainter than those previously detected at ≳ 10 keV and have a broad range in redshift and luminosity ( z = 0.020-2.923 and L10-40 keV ≈ 4 × 1041 -5 × 1045 erg s-1); the median redshift and luminosity are z ≈ 0.7 and L 10-40 keV ≈ 3 × 1044 erg s-1, respectively. We characterize these sources on the basis of broad-band ≈ 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L10-40 keV > 1044 erg s-1, of which ≈ 50% are obscured with NH ≳ 1022 cm-2. However, none of the 10 NuSTAR sources are Compton thick (NH ≳ 1024 cm-2) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L10-40 keV > 1044 erg s-1) selected at ≳ 10 keV of ≲ 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame ≈ 10-40 keV data for all of the non-beamed sources with L10-40 keV > 1043 erg s-1 to constrain the average strength of reflection; we find R <1.4 for Γ = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at ≳ 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of ≈ 1011 M⊙, a factor ≈ 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.",

author = "Alexander, {D. M.} and D. Stern and {Del Moro}, A. and Lansbury, {G. B.} and Assef, {R. J.} and J. Aird and M. Ajello and Ballantyne, {D. R.} and Bauer, {F. E.} and Boggs, {S. E.} and Brandt, {W. N.} and Christensen, {Finn Erland} and F. Civano and A. Comastri and Craig, {W. W.} and M. Elvis and Grefenstette, {B. W.} and Hailey, {C. J.} and Harrison, {F. A.} and Hickox, {R. C.} and B. Luo and Madsen, {K. K.} and Mullaney, {J. R.} and M. Perri and S. Puccetti and C. Saez and E. Treister and Urry, {C. M.} and Zhang, {W. W.} and Bridge, {C. R.} and Eisenhardt, {P. R. M.} and Gonzalez, {A. H.} and Miller, {S. H.} and Tsai, {C. W.}",

year = "2013",

doi = "10.1088/0004-637X/773/2/125",

language = "English",

volume = "773",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Alexander, DM, Stern, D, Del Moro, A, Lansbury, GB, Assef, RJ, Aird, J, Ajello, M, Ballantyne, DR, Bauer, FE, Boggs, SE, Brandt, WN, Christensen, FE, Civano, F, Comastri, A, Craig, WW, Elvis, M, Grefenstette, BW, Hailey, CJ, Harrison, FA, Hickox, RC, Luo, B, Madsen, KK, Mullaney, JR, Perri, M, Puccetti, S, Saez, C, Treister, E, Urry, CM, Zhang, WW, Bridge, CR, Eisenhardt, PRM, Gonzalez, AH, Miller, SH & Tsai, CW 2013, 'The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population', Astrophysical Journal, vol. 773, no. 2, 125. https://doi.org/10.1088/0004-637X/773/2/125

TY - JOUR

T1 - The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population

AU - Alexander, D. M.

AU - Stern, D.

AU - Del Moro, A.

AU - Lansbury, G. B.

AU - Assef, R. J.

AU - Aird, J.

AU - Ajello, M.

AU - Ballantyne, D. R.

AU - Bauer, F. E.

AU - Boggs, S. E.

AU - Brandt, W. N.

AU - Christensen, Finn Erland

AU - Civano, F.

AU - Comastri, A.

AU - Craig, W. W.

AU - Elvis, M.

AU - Grefenstette, B. W.

AU - Hailey, C. J.

AU - Harrison, F. A.

AU - Hickox, R. C.

AU - Luo, B.

AU - Madsen, K. K.

AU - Mullaney, J. R.

AU - Perri, M.

AU - Puccetti, S.

AU - Saez, C.

AU - Treister, E.

AU - Urry, C. M.

AU - Zhang, W. W.

AU - Bridge, C. R.

AU - Eisenhardt, P. R. M.

AU - Gonzalez, A. H.

AU - Miller, S. H.

AU - Tsai, C. W.

PY - 2013

Y1 - 2013

N2 - We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array ( NuSTAR ) to provide the first sensitive census of the cosmic X-ray background source population at ≳ 10 keV. We find that these NuSTAR -detected sources are ≈ 100 times fainter than those previously detected at ≳ 10 keV and have a broad range in redshift and luminosity ( z = 0.020-2.923 and L10-40 keV ≈ 4 × 1041 -5 × 1045 erg s-1); the median redshift and luminosity are z ≈ 0.7 and L 10-40 keV ≈ 3 × 1044 erg s-1, respectively. We characterize these sources on the basis of broad-band ≈ 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L10-40 keV > 1044 erg s-1, of which ≈ 50% are obscured with NH ≳ 1022 cm-2. However, none of the 10 NuSTAR sources are Compton thick (NH ≳ 1024 cm-2) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L10-40 keV > 1044 erg s-1) selected at ≳ 10 keV of ≲ 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame ≈ 10-40 keV data for all of the non-beamed sources with L10-40 keV > 1043 erg s-1 to constrain the average strength of reflection; we find R <1.4 for Γ = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at ≳ 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of ≈ 1011 M⊙, a factor ≈ 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

AB - We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array ( NuSTAR ) to provide the first sensitive census of the cosmic X-ray background source population at ≳ 10 keV. We find that these NuSTAR -detected sources are ≈ 100 times fainter than those previously detected at ≳ 10 keV and have a broad range in redshift and luminosity ( z = 0.020-2.923 and L10-40 keV ≈ 4 × 1041 -5 × 1045 erg s-1); the median redshift and luminosity are z ≈ 0.7 and L 10-40 keV ≈ 3 × 1044 erg s-1, respectively. We characterize these sources on the basis of broad-band ≈ 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L10-40 keV > 1044 erg s-1, of which ≈ 50% are obscured with NH ≳ 1022 cm-2. However, none of the 10 NuSTAR sources are Compton thick (NH ≳ 1024 cm-2) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L10-40 keV > 1044 erg s-1) selected at ≳ 10 keV of ≲ 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame ≈ 10-40 keV data for all of the non-beamed sources with L10-40 keV > 1043 erg s-1 to constrain the average strength of reflection; we find R <1.4 for Γ = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at ≳ 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of ≈ 1011 M⊙, a factor ≈ 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

U2 - 10.1088/0004-637X/773/2/125

DO - 10.1088/0004-637X/773/2/125

M3 - Journal article

SN - 0004-637X

VL - 773

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 125

ER -

The NuSTAR extragalactic survey: a first sensitive look at the high-energy cosmic x-ray background population

Abstract

Access to Document

OpenUrl availability

Fingerprint

Cite this