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Investigating the Covering Fraction Distribution of Swift/BAT AGNs with X-Ray and Infrared Observations

Lanz, Lauranne and Hickox, Ryan C. and Baloković, Mislav and Shimizu, Taro and Ricci, Claudio and Goulding, Andy D. and Ballantyne, David R. and Bauer, Franz E. and Chen, Chien-Ting J. and Del Moro, Agnese and Farrah, Duncan and Koss, Michael J. and LaMassa, Stephanie and Masini, Alberto and Zappacosta, Luca (2019) Investigating the Covering Fraction Distribution of Swift/BAT AGNs with X-Ray and Infrared Observations. Astrophysical Journal, 870 (1). Art. No. 26. ISSN 1538-4357. http://resolver.caltech.edu/CaltechAUTHORS:20181108-091558649

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Abstract

We present an analysis of a sample of 69 local obscured Swift/Burst Alert Telescope active galactic nuclei (AGNs) with X-ray spectra from NuSTAR and infrared (IR) spectral energy distributions from Herschel and WISE. We combine this X-ray and IR phenomenological modeling and find a significant correlation between reflected hard X-ray emission and IR AGN emission, with suggestive indications that this correlation may be stronger than the one between intrinsic hard X-ray and IR emissions. This relation between the IR and reflected X-ray emission suggests that both are the result of the processing of intrinsic emission from the corona and accretion disk by the same structure. We explore the resulting implications on the underlying distribution of covering fraction for all AGNs, by generating mock observables for the reflection parameter and IR luminosity ratio using empirical relations found for the covering fraction with each quantity. We find that the observed distributions of the reflection parameter and IR-to-X-ray ratio are reproduced with broad distributions centered around covering fractions of at least ~40%–50%, whereas narrower distributions match our observations only when centered around covering fractions of ~70%–80%. Our results are consistent with both independent estimates of the covering fractions of individual objects and the typical covering fraction obtained on the basis of obscured fractions for samples of AGNs. These results suggest that the level of reprocessing in AGNs, including X-ray reflection, is related in a relatively straightforward way to the geometry of the obscuring material.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-4357/aaee6cDOIArticle
https://arxiv.org/abs/1811.02570arXivDiscussion Paper
ORCID:
AuthorORCID
Lanz, Lauranne0000-0002-3249-8224
Hickox, Ryan C.0000-0003-1468-9526
Baloković, Mislav0000-0003-0476-6647
Shimizu, Taro0000-0002-2125-4670
Ricci, Claudio0000-0001-5231-2645
Ballantyne, David R.0000-0001-8128-6976
Bauer, Franz E.0000-0002-8686-8737
Chen, Chien-Ting J.0000-0002-4945-5079
Farrah, Duncan0000-0003-1748-2010
Koss, Michael J.0000-0002-7998-9581
LaMassa, Stephanie0000-0002-5907-3330
Zappacosta, Luca0000-0002-4205-6884
Alternate Title:Investigating the Covering Fraction Distribution of Swift/BAT AGN with X-ray and IR Observations
Additional Information:© 2018 The American Astronomical Society. Received 2017 December 22; revised 2018 October 25; accepted 2018 November 2; published 2018 December 31. We thank the referee for useful comments, which particularly strengthened the statistical analysis. L.L. and R.C.H. acknowledge support from NASA through grant No. NNX15AP24G. L.L. acknowledges support from NASA through grant No. NNX17AB58G. R.C.H acknowledges support from the National Science Foundation through CAREER grant No. 1554584. M.B. acknowledges support from NASA Headquarters under the NASA Earth and Space Science Fellowship Program, grant No. NNX14AQ07H, and support from the black hole Initiative, which is funded by a grant from the John Templeton Foundation. C.R. acknowledges the CONICYT+PAI (Convocatoria Nacional subvencion a instalacion en la academia convocatoria año 2017 PAI77170080) and financial support from FONDECYT 1141218, Basal-CATA PFB-06/2007, and the China-CONICYT fund. F.E.B. acknowledges support from CONICYT-Chile (Basal-CATA PFB-06/2007, FONDECYT Regular 1141218), the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant No. IC120009, awarded to The Millennium Institute of Astrophysics, MAS. M.K. acknowledges support from NASA through ADAP award No. NNH16CT03C. A.M. acknowledges support from the ASI/INAF through grant No. I/037/12/0-011/13. L.Z. acknowledges financial support under ASI/INAF contract No. I/037/12/0. This work made use of ASURV Rev. 1.2 (Lavalley et al. 1992), which implements the methods presented in Isobe et al. (1986). Facilities: Herschel - European Space Agency's Herschel space observatory, NuSTAR - , Swift - , WISE - .
Group:NuSTAR
Subject Keywords:galaxies: active – galaxies: nuclei – galaxies: Seyfert – X-rays: galaxies – infrared: galaxies
Record Number:CaltechAUTHORS:20181108-091558649
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20181108-091558649
Official Citation:Lauranne Lanz et al 2019 ApJ 870 26
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90746
Collection:CaltechAUTHORS
Deposited By: Joy Painter
Deposited On:08 Nov 2018 20:38
Last Modified:18 Jan 2019 23:22

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