Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/23968
Titolo: | Blazar candidates beyond redshift 4 observed by Swift | Autori: | Sbarrato, Tullia GHISELLINI, Gabriele TAGLIAFERRI, Gianpiero FOSCHINI, LUIGI Nardini, M. TAVECCHIO, Fabrizio Gehrels, N. |
Data pubblicazione: | 2015 | Rivista: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Numero: | 446 | Fascicolo: | 3 | Da pagina:: | 2483 | Abstract: | We have selected SDSS J222032.50+002537.5 and SDSS J142048.01+120545.9 as best blazar candidates out of a complete sample of extremely radio-loud quasars at z > 4, with highly massive black holes. We observed them and a third serendipitous candidate with similar features (PMN J2134-0419) in the X-rays with the Swift/XRT telescope, to confirm their blazar nature. We observed strong and hard X-ray fluxes (i.e. α_X ̃ ≪ap 0.6, where F(ν )∝ ν ^{-α_X} in the 0.3-10 keV observed energy range, ̃1-40 keV rest frame) in all three cases. This allowed us to classify our candidates as real blazars, being characterized by large Lorentz factors (̃13) and very small viewing angles (̃3°). All three sources have black hole masses exceeding 10<SUP>9</SUP> M<SUB>☉</SUB> and their classification provides intriguing constraints on supermassive black hole formation and evolution models. We confirm our earlier suggestion that there are different formation epochs of extremely massive black holes hosted in jetted (z ̃ 4) and non-jetted systems (z ̃ 2.5). | Acknowledgments: | We thank the anonymous referee for useful comments. This research made use of the NASA/IPAC Extragalactic Database (NED) and of the data products from the Wide-field Infrared Survey Explorer , which are operated by the Jet Propulsion Laboratory, Caltech, funded by the National Aeronautics and Space Administration. Part of this work is based on archival data, software and online services provided by the ASI Science Data Center (ASDC). We made also use of data supplied by the UK Swift Science Data Centre at the University of Leicester. | URI: | http://hdl.handle.net/20.500.12386/23968 | URL: | https://academic.oup.com/mnras/article/446/3/2483/2892664 | ISSN: | 0035-8711 | DOI: | 10.1093/mnras/stu2269 | Bibcode ADS: | 2015MNRAS.446.2483S | Fulltext: | open |
È visualizzato nelle collezioni: | 1.01 Articoli in rivista |
File in questo documento:
File | Descrizione | Dimensioni | Formato | |
---|---|---|---|---|
stu2269.pdf | 600.34 kB | Adobe PDF | Visualizza/apri |
Page view(s)
50
controllato il 24-apr-2024
Download(s)
17
controllato il 24-apr-2024
Google ScholarTM
Check
Altmetric
Altmetric
Tutti i documenti in DSpace sono pubblicati ad Accesso Aperto, salvo diversa indicazione per alcuni documenti specifici.