Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/34663
DC Field | Value | Language |
---|---|---|
dc.contributor.author | SEVERGNINI, Paola | en_US |
dc.contributor.author | CACCIANIGA, Alessandro | en_US |
dc.contributor.author | DELLA CECA, Roberto | en_US |
dc.date.accessioned | 2024-01-30T14:36:37Z | - |
dc.date.available | 2024-01-30T14:36:37Z | - |
dc.date.issued | 2012 | en_US |
dc.identifier.issn | 0004-6361 | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/34663 | - |
dc.description.abstract | Aims: We present a new efficient diagnostic method, based on mid-infrared and X-ray data, to select local (z < 0.1) Compton-thick AGN with the aim of estimating their surface and space density. Methods: We define a region in the X-ray-to-mid-IR [F(2-12 keV)/F25ν25] vs. X-ray color (HR) plane associated to Compton-thick AGN, i.e. [F(2-12 keV)/F25ν25] < 0.02 and HR > - 0.2. On the basis of this selection method we build up a sample of 43 Compton-thick AGN candidates using data from IRAS Point Source and 2XMM-Newton catalogues. In order to test the efficiency of the proposed method in selecting Compton-thick AGN we use the results of the X-ray spectral analysis performed on all the sources of our sample (presented in a parallel work). After taking into account the different selection effects, we have estimated the number of Compton-thick in the local Universe and their density down to the IRAS flux limit of F25 = 0.5 Jy. Results: We find that the diagnostic plot proposed here is an efficient method to select Compton-thick AGN in the nearby Universe since ~84% of the sources populating the proposed Compton-thick region are actually Compton-thick AGN. Twenty percent are newly-discovered Compton-thick AGN. We then estimate the surface density of Compton-thick AGN down to the IRAS PSC catalogue flux limit (F25 = 0.5 Jy) that turns out to be ρCT ~ 3 × 10-3 src deg-2. After estimating an equivalent IR-to-hard-X-ray limiting flux, we compare our result with those found with Swift-BAT. We find that the surface density derived here is a factor 4 above the density computed in the hard X-ray surveys. This difference is ascribed, at least in part, to a significant contribution (~60-90%) of the star-forming activity to the total 25 μm emission for the sources in our sample. By considering only the 25 μm AGN emission, we estimate a surface density of Compton-thick AGN which is consistent with the results found by hard X-ray surveys. Finally, we estimated the co-moving space density of Compton-thick AGN with intrinsic LX > 1043 erg s-1 (0.004 < z < 0.06): ΦC-thick ~ (3.5-0.5+4.5)×10-6 Mpc-3. The prediction for Compton-thick AGN based on the synthesis model of X-ray background in Gilli et al. (2007) is consistent with this value. | en_US |
dc.language.iso | eng | en_US |
dc.title | A new technique to efficiently select Compton-thick AGN | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.1051/0004-6361/201118417 | en_US |
dc.identifier.scopus | 2-s2.0-84861811040 | en_US |
dc.identifier.url | http://arxiv.org/abs/1204.4359v1 | en_US |
dc.identifier.url | https://www.aanda.org/articles/aa/full_html/2012/06/aa18417-11/aa18417-11.html | en_US |
dc.relation.medium | STAMPA | en_US |
dc.relation.volume | 542 | en_US |
dc.relation.firstpage | A46 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.numberofauthors | 3 | en_US |
dc.description.international | no | en_US |
dc.contributor.country | ITA | en_US |
dc.relation.scientificsector | FIS/05 - ASTRONOMIA E ASTROFISICA | en_US |
dc.relation.journal | ASTRONOMY & ASTROPHYSICS | en_US |
dc.type.miur | 262 Articolo in rivista | - |
dc.identifier.adsbibcode | 2012A&A...542A..46S | en_US |
dc.description.apc | no | 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.fulltext | With Fulltext | - |
item.cerifentitytype | Publications | - |
item.grantfulltext | open | - |
crisitem.journal.journalissn | 0004-6361 | - |
crisitem.journal.ance | E016240 | - |
crisitem.author.dept | O.A. Brera | - |
crisitem.author.dept | O.A. Brera | - |
crisitem.author.dept | O.A. Brera | - |
crisitem.author.orcid | 0000-0001-5619-5896 | - |
crisitem.author.orcid | 0000-0002-2339-8264 | - |
crisitem.author.orcid | 0000-0001-7551-2252 | - |
Appears in Collections: | 1.01 Articoli in rivista |
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AA_2012_542_A46.pdf | PDF editoriale | 286.51 kB | Adobe PDF | View/Open |
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