Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/29246
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Ding, N. | en_US |
dc.contributor.author | Luo, B. | en_US |
dc.contributor.author | Brandt, W. N. | en_US |
dc.contributor.author | Paolillo, Maurizio | en_US |
dc.contributor.author | Yang, G. | en_US |
dc.contributor.author | Lehmer, B. D. | en_US |
dc.contributor.author | Shemmer, O. | en_US |
dc.contributor.author | Schneider, D. P. | en_US |
dc.contributor.author | TOZZI, Paolo | en_US |
dc.contributor.author | Xue, Y. Q. | en_US |
dc.contributor.author | Zheng, X. C. | en_US |
dc.contributor.author | Gu, Q. S. | en_US |
dc.contributor.author | Koekemoer, A. M. | en_US |
dc.contributor.author | Vignali, C. | en_US |
dc.contributor.author | Vito, F. | en_US |
dc.contributor.author | Wang, J. X. | en_US |
dc.date.accessioned | 2020-12-28T16:36:10Z | - |
dc.date.available | 2020-12-28T16:36:10Z | - |
dc.date.issued | 2018 | en_US |
dc.identifier.issn | 0004-637X | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/29246 | - |
dc.description.abstract | In deep X-ray surveys, active galactic nuclei (AGNs) with a broad range of luminosities have been identified. However, cosmologically distant low-luminosity AGN (LLAGN, {L}<SUB>{{X</SUB>}}≲ {10}<SUP>42</SUP> erg s<SUP>-1</SUP>) identification still poses a challenge because of significant contamination from host galaxies. Based on the 7 Ms Chandra Deep Field-South (CDF-S) survey, the longest-timescale (∼17 years) deep X-ray survey to date, we utilize an X-ray variability selection technique to search for LLAGNs that remain unidentified among the CDF-S X-ray sources. We find 13 variable sources from 110 unclassified CDF-S X-ray sources. Except for one source that could be an ultraluminous X-ray source, the variability of the remaining 12 sources is most likely due to accreting supermassive black holes. These 12 AGN candidates have low intrinsic X-ray luminosities, with a median value of 7 × 10<SUP>40</SUP> erg s<SUP>-1</SUP>. They are generally not heavily obscured, with an average effective power-law photon index of 1.8. The fraction of variable AGNs in the CDF-S is independent of X-ray luminosity and is only restricted by the total number of observed net counts, confirming previous findings that X-ray variability is a near-ubiquitous property of AGNs over a wide range of luminosities. There is an anticorrelation between X-ray luminosity and variability amplitude for high-luminosity AGNs, but as the luminosity drops to ≲10<SUP>42</SUP> erg s<SUP>-1</SUP>, the variability amplitude no longer appears dependent on the luminosity. The entire observed luminosity-variability trend can be roughly reproduced by an empirical AGN variability model based on a broken power-law power spectral density function. | en_US |
dc.language.iso | eng | en_US |
dc.title | Variability-selected Low-luminosity Active Galactic Nuclei Candidates in the 7 Ms Chandra Deep Field-South | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.3847/1538-4357/aaea60 | en_US |
dc.identifier.scopus | 2-s2.0-85057614512 | en_US |
dc.identifier.isi | 000451432300001 | en_US |
dc.identifier.url | https://arxiv.org/abs/1810.09465 | en_US |
dc.identifier.url | https://iopscience.iop.org/article/10.3847/1538-4357/aaea60 | en_US |
dc.relation.medium | STAMPA | en_US |
dc.relation.volume | 868 | en_US |
dc.relation.issue | 2 | en_US |
dc.relation.firstpage | 88 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.numberofauthors | 16 | en_US |
dc.description.international | sì | en_US |
dc.contributor.country | ITA | en_US |
dc.contributor.country | USA | en_US |
dc.contributor.country | CHN | 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 | 2018ApJ...868...88D | 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 | 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.cerifentitytype | Publications | - |
item.grantfulltext | open | - |
item.fulltext | With Fulltext | - |
crisitem.author.dept | O.A. Capodimonte | - |
crisitem.author.dept | O.A. Arcetri | - |
crisitem.author.orcid | 0000-0003-4210-7693 | - |
crisitem.author.orcid | 0000-0003-3096-9966 | - |
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 | |
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Ding_2018_ApJ_868_88.pdf | Pdf editoriale | 2.18 MB | Adobe PDF | View/Open |
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