SIMBAD references

2019ApJ...872....8M - Astrophys. J., 872, 8-8 (2019/February-2)

Compton-thick AGNs in the NuSTAR era. III. A systematic study of the torus covering factor.

MARCHESI S., AJELLO M., ZHAO X., MARCOTULLI L., BALOKOVIC M., BRIGHTMAN M., COMASTRI A., CUSUMANO G., LANZUISI G., LA PAROLA V., SEGRETO A. and VIGNALI C.

Abstract (from CDS):

We present the analysis of a sample of 35 candidate Compton-thick active galactic nuclei (AGNs) selected in the nearby universe (average redshift <z>∼0.03) 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 (Balokovic 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.

Abstract Copyright: © 2019. The American Astronomical Society. All rights reserved.

Journal keyword(s): galaxies: active - galaxies: nuclei - X-rays: galaxies

Simbad objects: 36

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