SIMBAD references

2019ApJ...887..173L - Astrophys. J., 887, 173-173 (2019/December-3)

NuSTAR uncovers an extremely local Compton-thick AGN in NGC 4968.

LAMASSA S.M., YAQOOB T., BOORMAN P.G., TZANAVARIS P., LEVENSON N.A., GANDHI P., PTAK A.F. and HECKMAN T.M.

Abstract (from CDS):

We present the analysis of Chandra and NuSTAR spectra of NGC 4968, a local (D ∼ 44 Mpc) 12 µm selected Seyfert 2 galaxy, enshrouded within Compton-thick layers of obscuring gas. We find no evidence of variability between the Chandra and NuSTAR observations (separated by 2 yr), nor between the two NuSTAR observations (separated by 10 months). Using self-consistent X-ray models, we rule out the scenario where the obscuring medium is nearly spherical and uniform, contradicting the results implied by the <10 keV Chandra spectrum. The line-of-sight column density, from intervening matter between the source and observer that intercepts the intrinsic active galactic nucleus (AGN) X-ray emission, is well within the Compton-thick regime, with a minimum column density of 2 x 1024 cm–2. The average global column density is high (>3 x 1023 cm–2), with both Compton-thick and Compton-thin solutions permitted, depending on the X-ray spectral model. The spectral models provide a range of intrinsic AGN continuum parameters and implied 2-10 keV luminosities (L_2-10 keV,intrinsic_), where the higher end of L_2-10 keV,intrinsic_ is consistent with expectations from the 12 µm luminosity (L_2-10 keV,intrinisc_ ∼ 7 x 1042 erg s–1). Compared with Compton-thick AGN previously observed by NuSTAR, NGC 4968 is among the most intrinsically X-ray luminous. However, despite its close proximity and relatively high intrinsic X-ray luminosity, it is undetected by the 105 month Swift-Burst Alert Telescope survey, underscoring the importance of multiwavelength selection for obtaining the most complete census of the most hidden black holes.

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

Journal keyword(s): Active galactic nuclei - X-ray active galactic nuclei - Seyfert galaxies

Simbad objects: 18

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