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Published July 2022 | Version Published + Accepted Version
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BASS. XXIX. The Near-infrared View of the Broad-line Region (BLR): The Effects of Obscuration in BLR Characterization

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Abstract

Virial black hole (BH) mass (MBH) determination directly involves knowing the broad-line region (BLR) clouds' velocity distribution, their distance from the central supermassive BH (R_(BLR)), and the virial factor (f). Understanding whether biases arise in M_(BH) estimation with increasing obscuration is possible only by studying a large (N > 100) statistical sample of obscuration-unbiased (hard) X-ray-selected active galactic nuclei (AGNs) in the rest-frame near-infrared (0.8–2.5 μm) since it penetrates deeper into the BLR than the optical. We present a detailed analysis of 65 local Burst Alert Telescope (BAT) selected Seyfert galaxies observed with Magellan/FIRE. Adding these to the near-infrared BAT AGN spectroscopic survey database, we study a total of 314 unique near-infrared spectra. While the FWHMs of Hα and near-infrared broad lines (He i, Paβ, Paα) remain unbiased to either BLR extinction or X-ray obscuration, the Hα broad-line luminosity is suppressed when N_H ≳ 10²¹ cm⁻², systematically underestimating M_(BH) by 0.23–0.46 dex. Near-infrared line luminosities should be preferred to Hα until N_H < 10²² cm⁻², while at higher obscuration a less-biased R_(BLR) proxy should be adopted. We estimate f for Seyfert 1 and 2 using two obscuration-unbiased M_(BH) measurements, i.e., the stellar velocity dispersion and a BH mass prescription based on near-infrared and X-ray, and find that the virial factors do not depend on the redshift or obscuration, but some broad lines show a mild anticorrelation with M_(BH). Our results show the critical impact obscuration can have on BLR characterization and the importance of the near-infrared and X-rays for a less-biased view of the BLR.

Additional Information

© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2020 December 13; revised 2021 August 28; accepted 2021 August 30; published 2022 July 15. The BAT AGN Spectroscopic Survey Data Release 2. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. We thank the anonymous referee for the useful comments that improved our manuscript. F.R. thanks the LCO Instrument & Operations Support Specialists that supported our runs at LCO using Magellan/FIRE, and in particular G. Prieto for sharing the record of local weather data used to run the molecfit correction on our FIRE observations. We acknowledge support from FONDECYT Postdoctorado 3180506 (F.R.) and 3210157 (A.R.L.); from PRIN MIUR 2017 project "black hole winds and the Baryon Life Cycle of Galaxies: the stone-guest at the galaxy evolution supper," contract #2017PH3WAT (F.R.); FONDECYT Regular 1190818 (E.T., F.E.B.) and 1200495 (F.E.B., E.T.); ANID grants CATA-Basal AFB-170002 (F.R., E.T., F.E.B.) and ANID BASAL CATA ACE210002 and FB210003 (E.T., F.E.B., C.R.); ANID Anillo ACT172033 (E.T.); from Millennium Nucleus NCN19_058 TITANs (E.T.); and Chile's Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC12_009, awarded to The Millennium Institute of Astrophysics, MAS (F.E.B.); from NASA through ADAP award NNH16CT03C (M.K.); the ANID+PAI Convocatoria Nacional subvencion a instalacion en la academia convocatoria año 2017 PAI77170080 and Fondecyt Iniciacion grant 11190831 (C.R.); from the State Research Agency (AEI-MCINN) and from the Spanish MCIU under grant "Feeding and feedback in active galaxies" with reference PID2019-106027GB-C42 (P.S.B.); from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program, grant agreement 950533, and the Israel Science Foundation, grant No. 1849/19 (B.T.); the National Research Foundation of Korea (NRF-2020R1C1C1005462, K.O.); the Japan Society for the Promotion of Science (JSPS, ID: 17321, K.O.); the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. C.M.U. acknowledges support from the National Science Foundation under grant No. AST-1715512. We acknowledge support from the Comunidad de Madrid through the Atracción de Talento Investigador grant 2018-T1/TIC-11035 (I.L.). Facilities: Magellan-LCO - , Swift (BAT). - Software: FireHose (v2; Gagné et al. 2015), molecfit (Smette et al. 2015), pymccorrelation package (Privon et al. 2020), PySpecKit (v0.1.21; Ginsburg & Mirocha 2011).

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Accepted Version - 2111.13720.pdf

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Additional details

Additional titles

Alternative title
BASS XXIX: The near-infrared view of the BLR: the effects of obscuration in BLR characterisation

Identifiers

Eprint ID
115904
Resolver ID
CaltechAUTHORS:20220727-36915000

Related works

Describes
https://arxiv.org/abs/2111.13720 (URL)

Funding

Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
3180506
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
3210157
Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR)
2017PH3WAT
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
1190818
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
1200495
BASAL-CATA
AFB-170002
Agencia Nacional de Investigación y Desarrollo (ANID)
ACE210002
Agencia Nacional de Investigación y Desarrollo (ANID)
FB210003
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)
ACT172033
Agencia Nacional de Investigación y Desarrollo (ANID)
NCN19_058
Ministry of Economy, Development, and Tourism (Chile)
IC12_009
NASA
NNH16CT03C
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)
PAI77170080
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
11190831
Ministerio de Ciencia, Innovación y Universidades (MCIU)
PID2019-106027GB-C42
Agencia Estatal de Investigación
European Research Council (ERC)
950533
Israel Science Foundation
1849/19
National Research Foundation of Korea
NRF-2020R1C1C1005462
Japan Society for the Promotion of Science (JSPS)
17321
NASA/JPL/Caltech
NSF
AST-1715512
Comunidad de Madrid
2018-T1/TIC-11035

Dates

Created
2022-07-29
Created from EPrint's datestamp field
Updated
2022-07-29
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Caltech groups
Astronomy Department, Space Radiation Laboratory