NuSTAR J033202–2746.8: DIRECT CONSTRAINTS ON THE COMPTON REFLECTION IN A HEAVILY OBSCURED QUASAR AT z ≈ 2

Moro, A. Del; Mullaney, James; Alexander, D. M.; Comastri, A.; Bauer, F. E.; Treister, Ezequiel; Stern, Daniel; Civano, F.; Ranalli, P.; Vignali, C.; Aird, James; Ballantyne, D. R.; Baloković, Mislav; Boggs, Steven E.; Brandt, W. N.; Christensen, Finn Erland; Craig, William W.; Gandhi, P.; Gilli, R.; Hailey, Charles J.; Harrison, Fiona A.; Hickox, Ryan C.; LaMassa, Stephanie; Lansbury, G. B.; Puccetti, S.; Urry, C. Megan; Zhang, W. W.

doi:10.1088/0004-637x/786/1/16

Cited by 29 publications

(30 citation statements)

References 106 publications

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“…The rest-frame 10-40 keV energy range roughly corresponds to the observed 8-24 keV NuSTAR band (where we perform detection) for z ≈ 0.3-1 (where the bulk of our sample lies) and is becoming the standard for extragalactic NuSTAR surveys (e.g., Alexander et al 2013;Del Moro et al 2014).…”

Section: Kev -mentioning

confidence: 72%

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THENuSTAREXTRAGALACTIC SURVEY: FIRST DIRECT MEASUREMENTS OF THE ≳10 keV X-RAY LUMINOSITY FUNCTION FOR ACTIVE GALACTIC NUCLEI ATz> 0.1

Aird

Alexander

Ballantyne

et al. 2015

ApJ

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We present the first direct measurements of the rest-frame 10-40 keV X-ray luminosity function (XLF) of Active Galactic Nuclei (AGNs) based on a sample of 94 sources at 0.1 < z < 3, selected at 8-24 keV energies from sources in the NuSTAR extragalactic survey program. Our results are consistent with the strong evolution of the AGN population seen in prior, lower-energy studies of the XLF. However, different models of the intrinsic distribution of absorption, which are used to correct for selection biases, give significantly different predictions for the total number of sources in our sample, leading to small, systematic differences in our binned estimates of the XLF. Adopting a model with a lower intrinsic fraction of Compton-thick sources and a larger population of sources with column densities N H ∼ 10 23−24 cm −2 or a model with a stronger Compton reflection component (with a relative normalization of R ∼ 2 at all luminosities) can bring extrapolations of the XLF from 2-10 keV into agreement with our NuSTAR sample. Ultimately, X-ray spectral analysis of the NuSTAR sources is required to break this degeneracy between the distribution of absorbing column densities and the strength of the Compton reflection component and thus refine our measurements of the XLF. Furthermore, the models that successfully describe the high-redshift population seen by NuSTAR tend to over-predict previous, high-energy measurements of the local XLF, indicating that there is evolution of the AGN population that is not fully captured by the current models.

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Section: Kev -mentioning

confidence: 72%

“…X-ray spectral analysis of the NuSTAR sources is underway (see Alexander et al 2013;Del Moro et al 2014, A. Del Moro et al 2016, in preparation and L. Zappacosta et al 2016. For this study, we adopt the statistical approach used by A15.…”

Section: Kev -mentioning

confidence: 99%

THENuSTAREXTRAGALACTIC SURVEY: FIRST DIRECT MEASUREMENTS OF THE ≳10 keV X-RAY LUMINOSITY FUNCTION FOR ACTIVE GALACTIC NUCLEI ATz> 0.1

Aird

Alexander

Ballantyne

et al. 2015

ApJ

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“…The extent and strength of reflection in such sources, especially those with L * luminosities and at z 1 that make a large contribution to the CXB flux, is still a matter of debate (e.g. Vasudevan et al 2013;Del Moro et al 2014). Indeed, the CXB can be reproduced with a wide variety of models that assume different X-ray spectral models for the constituent AGNs, as well as different XLFs, NH distributions, and-perhaps most crucially-Comptonthick fractions (e.g.…”

Section: The Nh Distribution the Fraction Of Compton-thick Agns And mentioning

confidence: 99%

The evolution of the X-ray luminosity functions of unabsorbed and absorbed AGNs out to z∼ 5

Aird

Coil

Georgakakis

et al. 2015

Monthly Notices of the Royal Astronomical Society

375

559

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We present new measurements of the evolution of the X-ray luminosity functions (XLFs) of unabsorbed and absorbed Active Galactic Nuclei (AGNs) out to z ∼ 5. We construct samples containing 2957 sources detected at hard (2-7 keV) X-ray energies and 4351 sources detected at soft (0.5-2 keV) energies from a compilation of Chandra surveys supplemented by wide-area surveys from ASCA and ROSAT. We consider the hard and soft X-ray samples separately and find that the XLF based on either (initially neglecting absorption effects) is best described by a new flexible model parametrization where the break luminosity, normalization and faint-end slope all evolve with redshift. We then incorporate absorption effects, separately modelling the evolution of the XLFs of unabsorbed (20 < log N H < 22) and absorbed (22 < log N H < 24) AGNs, seeking a model that can reconcile both the hard-and soft-band samples. We find that the absorbed AGN XLF has a lower break luminosity, a higher normalization, and a steeper faint-end slope than the unabsorbed AGN XLF out to z ∼ 2. Hence, absorbed AGNs dominate at low luminosities, with the absorbed fraction falling rapidly as luminosity increases. Both XLFs undergo strong luminosity evolution which shifts the transition in the absorbed fraction to higher luminosities at higher redshifts. The evolution in the shape of the total XLF is primarily driven by the changing mix of unabsorbed and absorbed populations.

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“…For example, changing L i,X threshold values by±50% translates into a 3-5 factor difference in median and upper bound R values. A z=2 quasar selected in the NuSTAR-ECDF-S field and analyzed in Del Moro et al (2014) is reported in the plots as the starred data point. This source shows a low degree of reflection, comparable to the luminous/obscured AGN in our sample.…”

Section: The Reflection Componentmentioning

confidence: 99%

“…Lansbury et al (2017a) identified three similar sources at z 0.1 < that have even higher obscuration in the NuSTAR serendipitous survey. At high redshift, Del Moro et al (2014) presented the detection of a heavily absorbed (N 6 10 H 23 =´cm 2 -) quasar at z = 2. The redshift range and the luminosities probed by the NuSTAR extragalactic survey program are well-matched to CXB population-synthesis models, in terms of characterization of the AGN high-energy spectral shape and of the dominant obscured populations contributing to the CXB.…”

Section: Introductionmentioning

confidence: 99%

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

Zappacosta

Comastri

Civano

et al. 2018

ApJ

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We discuss the spectral analysis of a sample of 63 active galactic nuclei (AGN) detected above a limiting flux of S 8 24 keV 7 10 14 =´-( -) erg s cm 1 2 --in the multi-tiered NuSTAR extragalactic survey program. The sources span a redshift range z 0 2.1 = -(median z 0.58 á ñ = ). The spectral analysis is performed over the broad 0.5-24keV energy range, combining NuSTAR with Chandra and/or XMM-Newton data and employing empirical and physically motivated models. This constitutes the largest sample of AGN selected at 10 keV > to be homogeneously spectrally analyzed at these flux levels. We study the distribution of spectral parameters such as photon index, column density (N H ), reflection parameter (R), and 10-40keV luminosity (L X ). Heavily obscured ( N log cm 23AGN constitute ∼25% (15-17 sources) and ∼2-3% (1-2 sources) of the sample, respectively. The observed N H distribution agrees fairly well with predictions of cosmic X-ray background population-synthesis models (CXBPSM). We estimate the intrinsic fraction of AGN as a function of N H , accounting for the bias against obscured AGN in a flux-selected sample. The fraction of CT AGN relative to N log cm 20 24AGN is poorly constrained, formally in the range 2-56% (90% upper limit of 66%). We derived a fraction ( f abs ) of obscured AGN ( N log cm 22 24as a function of L X in agreement with CXBPSM and previous z 1 < X-ray determinations. Furthermore, f abs at z 0.1 0.5 = -and L log erg s 43.6 44.3agrees with observational measurements/trends obtained over larger redshift intervals. We report a significant anti-correlation of R with L X (confirmed by our companion paper on stacked spectra) with considerable scatter around the median R values.

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NuSTAR J033202–2746.8: DIRECT CONSTRAINTS ON THE COMPTON REFLECTION IN A HEAVILY OBSCURED QUASAR AT z ≈ 2

Cited by 29 publications

References 106 publications

THENuSTAREXTRAGALACTIC SURVEY: FIRST DIRECT MEASUREMENTS OF THE ≳10 keV X-RAY LUMINOSITY FUNCTION FOR ACTIVE GALACTIC NUCLEI ATz> 0.1

THENuSTAREXTRAGALACTIC SURVEY: FIRST DIRECT MEASUREMENTS OF THE ≳10 keV X-RAY LUMINOSITY FUNCTION FOR ACTIVE GALACTIC NUCLEI ATz> 0.1

The evolution of the X-ray luminosity functions of unabsorbed and absorbed AGNs out to z∼ 5

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

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