Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/23698
DC Field | Value | Language |
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dc.contributor.author | Lansbury, G. B. | en_US |
dc.contributor.author | Gandhi, P. | en_US |
dc.contributor.author | Alexander, D. M. | en_US |
dc.contributor.author | Assef, R. J. | en_US |
dc.contributor.author | Aird, J. | en_US |
dc.contributor.author | Annuar, A. | en_US |
dc.contributor.author | Ballantyne, D. R. | en_US |
dc.contributor.author | Baloković, M. | en_US |
dc.contributor.author | Bauer, F. E. | en_US |
dc.contributor.author | Boggs, S. E. | en_US |
dc.contributor.author | Brandt, W. N. | en_US |
dc.contributor.author | Brightman, M. | en_US |
dc.contributor.author | Christensen, F. E. | en_US |
dc.contributor.author | Civano, F. | en_US |
dc.contributor.author | COMASTRI, Andrea | en_US |
dc.contributor.author | Craig, W. W. | en_US |
dc.contributor.author | Del Moro, A. | en_US |
dc.contributor.author | Grefenstette, B. W. | en_US |
dc.contributor.author | Hailey, C. J. | en_US |
dc.contributor.author | Harrison, F. A. | en_US |
dc.contributor.author | Hickox, R. C. | en_US |
dc.contributor.author | Koss, M. | en_US |
dc.contributor.author | LaMassa, S. M. | en_US |
dc.contributor.author | Luo, B. | en_US |
dc.contributor.author | Puccetti, S. | en_US |
dc.contributor.author | Stern, D. | en_US |
dc.contributor.author | Treister, E. | en_US |
dc.contributor.author | Vignali, C. | en_US |
dc.contributor.author | ZAPPACOSTA, Luca | en_US |
dc.contributor.author | Zhang, W. W. | en_US |
dc.date.accessioned | 2020-03-30T12:48:54Z | - |
dc.date.available | 2020-03-30T12:48:54Z | - |
dc.date.issued | 2015 | en_US |
dc.identifier.issn | 0004-637X | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/23698 | - |
dc.description | We thank the referee for a careful review, which has improved this work. We acknowledge financial support from: the Science and Technology Facilities Council (STFC) grants ST/K501979/1 (G.B.L.), ST/J003697/1 (P.G.), ST/I001573/1 (D.M.A. and A.D.M.); the Leverhulme Trust (D.M.A.); Gemini-CONICYT grant 32120009 (R.J.A.); the ERC Advanced Grant FEEDBACK at the University of Cambridge (J.A.); NSF AST award 1008067 (D.R.B.); the NASA Earth and Space Science Fellowship Program, grant NNX14AQ07H (M.B.); CONICYT-Chile grants Basal-CATA PFB-06/2007 (F.E.B.), FONDECYT 1141218 (F.E.B.), and “EMBIGGEN” Anillo ACT1101 (F.E.B.); the Ministry of Economy, Development, and Tourism's Millennium Science Initiative grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS (F.E.B.); Caltech NuSTAR subcontract 44A-1092750 (W.N.B. and B.L.); NASA ADP grant NNX10AC99G (W.N.B. and B.L.); the Caltech Kingsley visitor program (A.C.); ASI/INAF grant I/037/12/0011/13 (A.C., S.P., C.V.); NASA ADAP award NNX12AE38G (R.C.H.); National Science Foundation grant 1211096 (R.C.H.); and Swiss National Science Foundation grant PP00P2_138979/1 (M.K.). We thank Andrew Ptak and Jianjun Jia for the useful correspondence. 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 , IRAS , NuSTAR , Sloan, Spitzer , Swift , WISE , XMM-Newton . | en |
dc.description.abstract | The intrinsic column density (N<SUB>H</SUB>) distribution of quasars is poorly known. At the high obscuration end of the quasar population and for redshifts z < 1, the X-ray spectra can only be reliably characterized using broad-band measurements that extend to energies above 10 keV. Using the hard X-ray observatory NuSTAR, along with archival Chandra and XMM-Newton data, we study the broad-band X-ray spectra of nine optically selected (from the SDSS), candidate Compton-thick (N<SUB>H</SUB> > 1.5 × 10<SUP>24</SUP> cm<SUP>-2</SUP>) type 2 quasars (CTQSO2s); five new NuSTAR observations are reported herein, and four have been previously published. The candidate CTQSO2s lie at z < 0.5, have observed [O iii] luminosities in the range 8.4\lt {log}({L}<SUB>[{{O</SUB>} {{III}}]}/{L}<SUB>☉ </SUB>)\lt 9.6, and show evidence for extreme, Compton-thick absorption when indirect absorption diagnostics are considered. Among the nine candidate CTQSO2s, five are detected by NuSTAR in the high-energy (8-24 keV) band: two are weakly detected at the ≈3σ confidence level and three are strongly detected with sufficient counts for spectral modeling (≳90 net source counts at 8-24 keV). For these NuSTAR-detected sources direct (i.e., X-ray spectral) constraints on the intrinsic active galactic nucleus properties are feasible, and we measure column densities ≈2.5-1600 times higher and intrinsic (unabsorbed) X-ray luminosities ≈10-70 times higher than pre-NuSTAR constraints from Chandra and XMM-Newton. Assuming the NuSTAR-detected type 2 quasars are representative of other Compton-thick candidates, we make a correction to the N<SUB>H</SUB> distribution for optically selected type 2 quasars as measured by Chandra and XMM-Newton for 39 objects. With this approach, we predict a Compton-thick fraction of {f}<SUB>{CT</SUB>}={36}<SUB>-12</SUB><SUP>+14</SUP> %, although higher fractions (up to 76%) are possible if indirect absorption diagnostics are assumed to be reliable. | en_US |
dc.language.iso | eng | en_US |
dc.title | NuSTAR Reveals Extreme Absorption in z < 0.5 Type 2 Quasars | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.1088/0004-637X/809/2/115 | en_US |
dc.identifier.scopus | 2-s2.0-84939780982 | en_US |
dc.identifier.isi | 000361655100008 | en_US |
dc.identifier.url | https://iopscience.iop.org/article/10.1088/0004-637X/809/2/115 | en_US |
dc.relation.medium | STAMPA | en_US |
dc.relation.volume | 809 | en_US |
dc.relation.issue | 2 | en_US |
dc.relation.firstpage | 115 | en_US |
dc.relation.lastpage | 123 | en_US |
dc.relation.numberofpages | 19 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.numberofauthors | 30 | en_US |
dc.description.international | sì | en_US |
dc.contributor.country | ITA | en_US |
dc.contributor.country | USA | en_US |
dc.relation.scientificsector | FIS/05 - ASTRONOMIA E ASTROFISICA | en_US |
dc.relation.journal | THE ASTROPHYSICAL JOURNAL | en_US |
dc.type.miur | 262 Articolo in rivista | - |
dc.identifier.adsbibcode | 2015ApJ...809..115L | en_US |
dc.relation.ercsector | Scienze Fisiche Settori ERC (ERC) di riferimento::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation | en_US |
dc.description.apc | sì | en_US |
dc.description.oa | 1 – prodotto con file in versione Open Access (allegherò il file al passo 5-Carica) | en_US |
item.grantfulltext | open | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.fulltext | With Fulltext | - |
item.languageiso639-1 | en | - |
item.openairetype | Article | - |
item.cerifentitytype | Publications | - |
crisitem.journal.journalissn | 0004-637X | - |
crisitem.journal.ance | E016252 | - |
crisitem.author.dept | OAS Bologna | - |
crisitem.author.dept | O.A. Roma | - |
crisitem.author.orcid | 0000-0003-3451-9970 | - |
crisitem.author.orcid | 0000-0002-4205-6884 | - |
Appears in Collections: | 1.01 Articoli in rivista |
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File | Description | Size | Format | |
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Lansbury_2015_ApJ_809_115.pdf | 1.48 MB | Adobe PDF | View/Open |
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