Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/26879
DC Field | Value | Language |
---|---|---|
dc.contributor.author | CAPPELLUTI, Nico | en_US |
dc.contributor.author | Li, Yanxia | en_US |
dc.contributor.author | Ricarte, Angelo | en_US |
dc.contributor.author | Agarwal, Bhaskar | en_US |
dc.contributor.author | ALLEVATO, VIOLA | en_US |
dc.contributor.author | Tasnim Ananna, Tonima | en_US |
dc.contributor.author | Ajello, Marco | en_US |
dc.contributor.author | Civano, Francesca | en_US |
dc.contributor.author | COMASTRI, Andrea | en_US |
dc.contributor.author | Elvis, Martin | en_US |
dc.contributor.author | Finoguenov, Alexis | en_US |
dc.contributor.author | GILLI, Roberto | en_US |
dc.contributor.author | Hasinger, Günther | en_US |
dc.contributor.author | MARCHESI, STEFANO | en_US |
dc.contributor.author | Natarajan, Priyamvada | en_US |
dc.contributor.author | Pacucci, Fabio | en_US |
dc.contributor.author | Treister, E. | en_US |
dc.contributor.author | Urry, C. Megan | en_US |
dc.date.accessioned | 2020-08-27T12:43:23Z | - |
dc.date.available | 2020-08-27T12:43:23Z | - |
dc.date.issued | 2017 | en_US |
dc.identifier.issn | 0004-637X | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/26879 | - |
dc.description.abstract | Using Chandra observations in the 2.15 deg<SUP>2</SUP> COSMOS-legacy field, we present one of the most accurate measurements of the Cosmic X-ray Background (CXB) spectrum to date in the [0.3-7] keV energy band. The CXB has three distinct components: contributions from two Galactic collisional thermal plasmas at kT ∼ 0.27 and 0.07 keV and an extragalactic power law with a photon spectral index Γ = 1.45 ± 0.02. The 1 keV normalization of the extragalactic component is 10.91 ± 0.16 keV cm<SUP>-2</SUP> s<SUP>-1</SUP> sr<SUP>-1</SUP> keV<SUP>-1</SUP>. Removing all X-ray-detected sources, the remaining unresolved CXB is best fit by a power law with normalization 4.18 ± 0.26 keV cm<SUP>-2</SUP> s<SUP>-1</SUP> sr<SUP>-1</SUP> keV<SUP>-1</SUP> and photon spectral index Γ = 1.57 ± 0.10. Removing faint galaxies down to {I}<SUB>{AB</SUB>}∼ 27{--}28 leaves a hard spectrum with {{Γ }}∼ 1.25 and a 1 keV normalization of ∼1.37 keV cm<SUP>-2</SUP> s<SUP>-1</SUP> sr<SUP>-1</SUP> keV<SUP>-1</SUP>. This means that ∼91% of the observed CXB is resolved into detected X-ray sources and undetected galaxies. Unresolved sources that contribute ∼8%-9% of the total CXB show marginal evidence of being harder and possibly more obscured than resolved sources. Another ∼1% of the CXB can be attributed to still undetected star-forming galaxies and absorbed active galactic nuclei. According to these limits, we investigate a scenario where early black holes totally account for non-source CXB fraction and constrain some of their properties. In order to not exceed the remaining CXB and the z∼ 6 accreted mass density, such a population of black holes must grow in Compton-thick envelopes with {N}<SUB>H</SUB> > 1.6 × 10<SUP>25</SUP> cm<SUP>-2</SUP> and form in extremely low-metallicity environments ({Z}<SUB>☉ </SUB>)∼ {10}<SUP>-3</SUP>. | en_US |
dc.language.iso | eng | en_US |
dc.title | The Chandra COSMOS Legacy Survey: Energy Spectrum of the Cosmic X-Ray Background and Constraints on Undetected Populations | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.3847/1538-4357/aa5ea4 | en_US |
dc.identifier.scopus | 2-s2.0-85015154606 | en_US |
dc.identifier.isi | 000401170800004 | en_US |
dc.identifier.url | https://iopscience.iop.org/article/10.3847/1538-4357/aa5ea4 | en_US |
dc.relation.medium | STAMPA | en_US |
dc.relation.volume | 837 | en_US |
dc.relation.issue | 1 | en_US |
dc.relation.firstpage | 19 | en_US |
dc.relation.lastpage | 26 | en_US |
dc.relation.numberofpages | 8 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.international | sì | 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 | 2017ApJ...837...19C | en_US |
dc.relation.ercsector | ERC sectors::Physical Sciences and Engineering::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 (allegare il file al passo 5-Carica) | en_US |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.openairetype | Article | - |
item.languageiso639-1 | en | - |
item.cerifentitytype | Publications | - |
item.grantfulltext | open | - |
item.fulltext | With Fulltext | - |
crisitem.author.dept | OAS Bologna | - |
crisitem.author.dept | OAS Bologna | - |
crisitem.author.dept | OAS Bologna | - |
crisitem.author.orcid | 0000-0003-3451-9970 | - |
crisitem.author.orcid | 0000-0001-8121-6177 | - |
crisitem.author.orcid | 0000-0001-5544-0749 | - |
crisitem.journal.journalissn | 0004-637X | - |
crisitem.journal.ance | E016252 | - |
Appears in Collections: | 1.01 Articoli in rivista |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Cappelluti_2017_ApJ_837_19.pdf | pdf editoriale | 769.45 kB | Adobe PDF | View/Open |
1702.01660.pdf | preprint | 343.83 kB | Adobe PDF | View/Open |
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