We present the combined Chandra and Swift-BAT spectral analysis of nine low-redshift (z<= 0.10), candidate heavily obscured active galactic nuclei (AGN) selected from the Swift-BAT 150 month catalog. We located soft (1-10 keV) X-ray counterparts to these BAT sources and joint fit their spectra with physically motivated models. The spectral analysis in the 1-150 keV energy band determined that all sources are obscured, with a line-of-sight column density NH>=1E22 cm-2 at a 90% confidence level. Four of these sources show significant obscuration with NH>=1E23 cm-2 and two additional sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs) with NH>=1E24 cm-2. These two sources, 2MASX J02051994-0233055 and IRAS 11058-1131, are the latest addition to the previous 3 CT-AGN candidates found using our strategy for soft X-ray follow-up of BAT sources. Here we present the results of our methodology so far, and analyze the effectiveness of applying different selection criteria to discover CT-AGN in the local Universe. Our selection criteria has an ∼20% success rate of discovering heavily obscured AGN whose CT nature is confirmed by follow-up NuSTAR observations. This is much higher than the ∼5% found in blind surveys.
Silver R., Torres-Alba N., Zhao X., Marchesi S., Pizzetti A., Ajello M., et al. (2022). Chandra Follow-up Observations of Swift-BAT-selected AGNs II. THE ASTROPHYSICAL JOURNAL, 932(1), 1-20 [10.3847/1538-4357/ac67a2].
Chandra Follow-up Observations of Swift-BAT-selected AGNs II
Marchesi S.Conceptualization
;Comastri A.
2022
Abstract
We present the combined Chandra and Swift-BAT spectral analysis of nine low-redshift (z<= 0.10), candidate heavily obscured active galactic nuclei (AGN) selected from the Swift-BAT 150 month catalog. We located soft (1-10 keV) X-ray counterparts to these BAT sources and joint fit their spectra with physically motivated models. The spectral analysis in the 1-150 keV energy band determined that all sources are obscured, with a line-of-sight column density NH>=1E22 cm-2 at a 90% confidence level. Four of these sources show significant obscuration with NH>=1E23 cm-2 and two additional sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs) with NH>=1E24 cm-2. These two sources, 2MASX J02051994-0233055 and IRAS 11058-1131, are the latest addition to the previous 3 CT-AGN candidates found using our strategy for soft X-ray follow-up of BAT sources. Here we present the results of our methodology so far, and analyze the effectiveness of applying different selection criteria to discover CT-AGN in the local Universe. Our selection criteria has an ∼20% success rate of discovering heavily obscured AGN whose CT nature is confirmed by follow-up NuSTAR observations. This is much higher than the ∼5% found in blind surveys.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
