Details

Autor(en) / Beteiligte

• Marchesi, S.
• Ajello, M.
• Zhao, X.
• Marcotulli, L.
• Balokovi, M.
• Brightman, M.
• Comastri, A.
• Cusumano, G.
• Lanzuisi, G.
• La Parola, V.
• Segreto, A.
• Vignali, C.

Titel

Compton-thick AGNs in the NuSTAR Era. III. A Systematic Study of the Torus Covering Factor

Ist Teil von

• The Astrophysical journal, 2019-02, Vol.872 (1), p.8

Ort / Verlag

Philadelphia: The American Astronomical Society

Erscheinungsjahr

2019

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present the analysis of a sample of 35 candidate Compton-thick active galactic nuclei (AGNs) selected in the nearby universe (average redshift ) with the Swift-BAT 100-month survey. All sources have available NuSTAR data, thus allowing us to constrain with unprecedented quality important spectral parameters such as the obscuring torus line-of-sight column density (NH,z), the average torus column density (NH,tor), and the torus covering factor (fc). We compare the best-fit results obtained with the widely used MYTorus (Murphy & Yaqoob 2009) model with those of the recently published borus02 model (Balokovi et al. 2018) used in the same geometrical configuration of MYTorus (i.e., with fc = 0.5). We find a remarkable agreement between the two, although with increasing dispersion in NH,z moving toward higher column densities. We then use borus02 to measure fc. High-fc sources have, on average, smaller offset between NH,z and NH,tor than low-fc ones. Therefore, low fc values can be linked to a "patchy torus" scenario, where the AGN is seen through an overdense region in the torus, while high-fc objects are more likely to be obscured by a more uniform gas distribution. Finally, we find potential evidence of an inverse trend between fc and the AGN 2-10 keV luminosity, i.e., sources with higher fc values have on average lower luminosities.