We present the combined Chandra and Swift-BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift-BAT 100 month catalog. We selected nearby (z<=0.03) sources lacking a ROSAT counterpart that never previously been observed with Chandra in the 0.3-10 keV energy range, and targeted these objects with 10 ks Chandra ACIS-S observations. The X-ray spectral fitting over the 0.3-150 keV energy range allows us to determine that all the objects are significantly obscured, with NH>=1E23 cm-2 at a >99% confidence level. Moreover, one to three sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs; i.e., NH>1E24 cm-2). We also test the recent spectral curvature method developed by Koss et al. to find candidate CT-AGNs, finding a good agreement between our results and their predictions. Because the selection criteria we adopted were effective in detecting highly obscured AGNs, further observations of these and other Seyfert 2 galaxies selected from the Swift-BAT 100 month catalog will allow us to create a statistically significant sample of highly obscured AGNs, therefore providing a better understanding of the physics of the obscuration processes.
Marchesi S., Ajello M., Comastri A., Cusumano G., Parola V.L., Segreto A. (2017). X-Ray Spectral Properties of Seven Heavily Obscured Seyfert 2 Galaxies. THE ASTROPHYSICAL JOURNAL, 836(1), 1-8 [10.3847/1538-4357/836/1/116].
X-Ray Spectral Properties of Seven Heavily Obscured Seyfert 2 Galaxies
Marchesi S.
Primo
Conceptualization
;Comastri A.;
2017
Abstract
We present the combined Chandra and Swift-BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift-BAT 100 month catalog. We selected nearby (z<=0.03) sources lacking a ROSAT counterpart that never previously been observed with Chandra in the 0.3-10 keV energy range, and targeted these objects with 10 ks Chandra ACIS-S observations. The X-ray spectral fitting over the 0.3-150 keV energy range allows us to determine that all the objects are significantly obscured, with NH>=1E23 cm-2 at a >99% confidence level. Moreover, one to three sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs; i.e., NH>1E24 cm-2). We also test the recent spectral curvature method developed by Koss et al. to find candidate CT-AGNs, finding a good agreement between our results and their predictions. Because the selection criteria we adopted were effective in detecting highly obscured AGNs, further observations of these and other Seyfert 2 galaxies selected from the Swift-BAT 100 month catalog will allow us to create a statistically significant sample of highly obscured AGNs, therefore providing a better understanding of the physics of the obscuration processes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.