Please use this identifier to cite or link to this item:
http://hdl.handle.net/2445/142068
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DC Field | Value | Language |
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dc.contributor.author | Marchesi, Simone | - |
dc.contributor.author | Lanzuisi, G. | - |
dc.contributor.author | Civano, F. | - |
dc.contributor.author | Iwasawa, Kazushi | - |
dc.contributor.author | Suh, H. | - |
dc.contributor.author | Comastri, A. | - |
dc.contributor.author | Zamorani, G. | - |
dc.contributor.author | Allevato, V. | - |
dc.contributor.author | Griffiths, R. | - |
dc.contributor.author | Miyaji, T. | - |
dc.contributor.author | Ranalli, P. | - |
dc.contributor.author | Salvato, M. | - |
dc.contributor.author | Schawinski, K. | - |
dc.contributor.author | Silverman, John D. | - |
dc.contributor.author | Treister, E. | - |
dc.contributor.author | Urry, C. M. | - |
dc.contributor.author | Vignali, C. | - |
dc.date.accessioned | 2019-10-10T11:03:58Z | - |
dc.date.available | 2019-10-10T11:03:58Z | - |
dc.date.issued | 2016-10-20 | - |
dc.identifier.issn | 0004-637X | - |
dc.identifier.uri | http://hdl.handle.net/2445/142068 | - |
dc.description.abstract | We present the X-ray spectral analysis of the 1855 extragalactic sources in the Chandra COSMOS-Legacy survey catalog having more than 30 net counts in the 0.5-7 keV band. A total of 38% of the sources are optically classified type 1 active galactic nuclei (AGNs), 60% are type 2 AGNs, and 2% are passive, low-redshift galaxies. We study the distribution of AGN photon index Γ and of the intrinsic absorption ${N}_{{\rm{H}},{\rm{z}}}$ based on the sources' optical classification: type 1 AGNs have a slightly steeper mean photon index Γ than type 2 AGNs, which, on the other hand, have average ${N}_{{\rm{H}},{\rm{z}}}\,\sim 3$ times higher than type 1 AGNs. We find that ~15% of type 1 AGNs have ${N}_{{\rm{H}},{\rm{z}}}\gt {10}^{22}$ cm−2, i.e., are obscured according to the X-ray spectral fitting; the vast majority of these sources have ${L}_{2\mbox{--}10\mathrm{keV}}\,\gt $ 1044 erg s−1. The existence of these objects suggests that optical and X-ray obscuration can be caused by different phenomena, the X-ray obscuration being, for example, caused by dust-free material surrounding the inner part of the nuclei. Approximately 18% of type 2 AGNs have ${N}_{{\rm{H}},{\rm{z}}}\lt {10}^{22}$ cm−2, and most of these sources have low X-ray luminosities (L ${}_{2\mbox{--}10\mathrm{keV}}\,\lt $ 1043 erg s−1). We expect a part of these sources to be low-accretion, unobscured AGNs lacking broad emission lines. Finally, we also find a direct proportional trend between ${N}_{{\rm{H}},{\rm{z}}}$ and host-galaxy mass and star formation rate, although part of this trend is due to a redshift selection effect. | - |
dc.format.extent | 20 p. | - |
dc.format.mimetype | application/pdf | - |
dc.language.iso | eng | - |
dc.publisher | Institute of Physics (IOP) | - |
dc.relation.isformatof | Reproducció del document publicat a: https://doi.org/10.3847/0004-637X/830/2/100 | - |
dc.relation.ispartof | Astrophysical Journal, 2016, vol. 830, num. 2 | - |
dc.relation.uri | https://doi.org/10.3847/0004-637X/830/2/100 | - |
dc.rights | (c) American Astronomical Society, 2016 | - |
dc.source | Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB)) | - |
dc.subject.classification | Cosmologia | - |
dc.subject.classification | Espectrometria de raigs beta | - |
dc.subject.other | Cosmology | - |
dc.subject.other | Beta ray spectrometry | - |
dc.title | The Chandra COSMOS-Legacy Survey: Source X-Ray Spectral Properties | - |
dc.type | info:eu-repo/semantics/article | - |
dc.type | info:eu-repo/semantics/publishedVersion | - |
dc.identifier.idgrec | 669899 | - |
dc.date.updated | 2019-10-10T11:03:58Z | - |
dc.rights.accessRights | info:eu-repo/semantics/openAccess | - |
Appears in Collections: | Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB)) |
Files in This Item:
File | Description | Size | Format | |
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669899.pdf | 1.89 MB | Adobe PDF | View/Open |
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