BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission
Abstract
We provide a comprehensive census of the near-infrared (NIR, 0.8–2.4 μm) spectroscopic properties of 102 nearby (z < 0.075) active galactic nuclei (AGN), selected in the hard X-ray band (14–195 keV) from the Swift-Burst Alert Telescope survey. With the launch of the James Webb Space Telescope, this regime is of increasing importance for dusty and obscured AGN surveys. We measure black hole masses in 68 per cent (69/102) of the sample using broad emission lines (34/102) and/or the velocity dispersion of the Ca ii triplet or the CO band-heads (46/102). We find that emission-line diagnostics in the NIR are ineffective at identifying bright, nearby AGN galaxies because [Fe ii] 1.257 μm/Paβ and H2 2.12 μm/Brγ identify only 25 per cent (25/102) as AGN with significant overlap with star-forming galaxies and only 20 per cent of Seyfert 2 have detected coronal lines (6/30). We measure the coronal line emission in Seyfert 2 to be weaker than in Seyfert 1 of the same bolometric luminosity suggesting obscuration by the nuclear torus. We find that the correlation between the hard X-ray and the [Si vi] coronal line luminosity is significantly better than with the [O iii] λ5007 luminosity. Finally, we find 3/29 galaxies (10 per cent) that are optically classified as Seyfert 2 show broad emission lines in the NIR. These AGN have the lowest levels of obscuration among the Seyfert 2s in our sample (log NH < 22.43 cm^(−2)), and all show signs of galaxy-scale interactions or mergers suggesting that the optical broad emission lines are obscured by host galaxy dust.
Additional Information
© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 January 9. Received 2017 January 9; in original form 2016 September 30. We thank the anonymous referee for the helpful comments. MK acknowledges support from the Swiss National Science Foundation (SNSF) through the Ambizione fellowship grant PZ00P2_154799/1. MK was a visiting astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration (IRTF programmes 2010A-059, 2011A-077, 2011B-104, 2012A-083). The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We acknowledge the work that the Swift/BAT team has done to make this work possible. The Kitt Peak National Observatory observations were obtained using MD-TAC time as part of the thesis of MK (2008B-0426, 2009A-0287, 2009B-0569) and also through NOAO time in programme 2010A-0447 (PI M. Koss). Kitt Peak National Observatory, National Optical Astronomy Observatory, is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation. Data from Gemini programmes (GN-2011B-Q-111,GN-2012A-Q-23, GN-2012B-Q-80, GN-2013A-Q-16, GN-2013A-Q-120) were used in this publication. MK would like to thank Dick Joyce at the NOAO for teaching him how to use the FLAMINGOS spectrograph on his first NIR spectroscopy run, the help of John Rayner with SPEX, and Michael Cushing for help with spextool. KS gratefully acknowledges support from Swiss National Science Foundation Grant PP00P2_138979/1. CR acknowledges financial support from the CONICYT-Chile 'EMBIGGEN' Anillo (grant ACT1101), FONDECYT 1141218 and Basal-CATA PFB–06/2007. AR-A acknowledges the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for partial support to this work (grant 311935/2015-0). RR acknowledges support from CNPq and FAPERGS. This research made use of astropy, a community-developed core python package for astronomy (Astropy Collaboration, 2013). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.Attached Files
Published - stx055.pdf
Submitted - 1701.02755.pdf
Supplemental Material - stx055_Supp.zip
Files
Additional details
- Eprint ID
- 77201
- Resolver ID
- CaltechAUTHORS:20170505-065741597
- PZ00P2_154799/1
- Swiss National Science Foundation (SNSF)
- NNH14CK55B
- NASA
- PP00P2_138979/1
- Swiss National Science Foundation (SNSF)
- ACT1101
- Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)
- 1141218
- Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
- PFB-06/2007
- Basal-CATA
- 311935/2015-0
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
- Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS)
- NASA/JPL/Caltech
- Created
-
2017-05-05Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC), Space Radiation Laboratory, Astronomy Department