We present the 2-100 keV spectral analysis of 30 candidate Compton-thick-(CT-)active galactic nuclei (AGNs) selected in the Swift-Burst Alert Telescope (BAT) 100 month survey. The average redshift of these objects is , and they all lie within â¼500 Mpc. We used the MyTorus model to perform X-ray spectral fittings both without and with the contribution of the Nuclear Spectroscopic Telescope Array (NuSTAR) data in the 3-50 keV energy range. When the NuSTAR data are added to the fit, 13 out of 30 of these objects (43% of the whole sample) have intrinsic absorption NH< 1024cm-2at the >3Ï confidence level, i.e., they are reclassified from Compton thick to Compton thin. Consequently, we infer an overall observed fraction of the CT-AGN, with respect to the whole AGN population, lower than the one reported in previous works, as low as â¼4%. We find evidence that this overestimation of NHis likely due to the low quality of a subsample of spectra, either in the 2-10 keV band or in the Swift-BAT one.
Compton-thick AGNs in the NuSTAR Era / Marchesi, S.; Ajello, M.; Marcotulli, L.; Comastri, A.; Lanzuisi, G.; Vignali, C.. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - STAMPA. - 854:1(2018), pp. 49-64. [10.3847/1538-4357/aaa410]
Compton-thick AGNs in the NuSTAR Era
Marchesi, S.
Writing – Original Draft Preparation
;Lanzuisi, G.Membro del Collaboration Group
;Vignali, C.Membro del Collaboration Group
2018
Abstract
We present the 2-100 keV spectral analysis of 30 candidate Compton-thick-(CT-)active galactic nuclei (AGNs) selected in the Swift-Burst Alert Telescope (BAT) 100 month survey. The average redshift of these objects is , and they all lie within â¼500 Mpc. We used the MyTorus model to perform X-ray spectral fittings both without and with the contribution of the Nuclear Spectroscopic Telescope Array (NuSTAR) data in the 3-50 keV energy range. When the NuSTAR data are added to the fit, 13 out of 30 of these objects (43% of the whole sample) have intrinsic absorption NH< 1024cm-2at the >3Ï confidence level, i.e., they are reclassified from Compton thick to Compton thin. Consequently, we infer an overall observed fraction of the CT-AGN, with respect to the whole AGN population, lower than the one reported in previous works, as low as â¼4%. We find evidence that this overestimation of NHis likely due to the low quality of a subsample of spectra, either in the 2-10 keV band or in the Swift-BAT one.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
