BASS. XXV. DR2 Broad-line-based Black Hole Mass Estimates and Biases from Obscuration

Autor: Julian E. Mejía-Restrepo, Benny Trakhtenbrot, Michael J. Koss, Kyuseok Oh, Jakob den Brok, Daniel Stern, Meredith C. Powell, Federica Ricci, Turgay Caglar, Claudio Ricci, Franz E. Bauer, Ezequiel Treister, Fiona A. Harrison, C. M. Urry, Tonima Tasnim Ananna, Daniel Asmus, Roberto J. Assef, Rudolf E. Bär, Patricia S. Bessiere, Leonard Burtscher, Kohei Ichikawa, Darshan Kakkad, Nikita Kamraj, Richard Mushotzky, George C. Privon, Alejandra F. Rojas, Eleonora Sani, Kevin Schawinski, Sylvain Veilleux
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: The Astrophysical Journal Supplement Series, Vol 261, Iss 1, p 5 (2022)
Druh dokumentu: article
ISSN: 1538-4365
0067-0049
DOI: 10.3847/1538-4365/ac6602
Popis: We present measurements of broad emission lines and virial estimates of supermassive black hole masses ( M _BH ) for a large sample of ultrahard X-ray-selected active galactic nuclei (AGNs) as part of the second data release of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes M _BH estimates for a total of 689 AGNs, determined from the H α , H β , Mg ii λ 2798, and/or C iv λ 1549 broad emission lines. The core sample includes a total of 512 AGNs drawn from the 70 month Swift/BAT all-sky catalog. We also provide measurements for 177 additional AGNs that are drawn from deeper Swift/BAT survey data. We study the links between M _BH estimates and line-of-sight obscuration measured from X-ray spectral analysis. We find that broad H α emission lines in obscured AGNs ( $\mathrm{log}({N}_{{\rm{H}}}/{\mathrm{cm}}^{-2})\gt 22.0$ ) are on average a factor of ${8.0}_{-2.4}^{+4.1}$ weaker relative to ultrahard X-ray emission and about ${35}_{-12}^{\,+7}$ % narrower than those in unobscured sources (i.e., $\mathrm{log}({N}_{{\rm{H}}}/{\mathrm{cm}}^{-2})\lt 21.5$ ). This indicates that the innermost part of the broad-line region is preferentially absorbed. Consequently, current single-epoch M _BH prescriptions result in severely underestimated (>1 dex) masses for Type 1.9 sources (AGNs with broad H α but no broad H β ) and/or sources with $\mathrm{log}({N}_{{\rm{H}}}/{\mathrm{cm}}^{-2})\gtrsim 22.0$ . We provide simple multiplicative corrections for the observed luminosity and width of the broad H α component ( L [bH α ] and FWHM[bH α ]) in such sources to account for this effect and to (partially) remedy M _BH estimates for Type 1.9 objects. As a key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift universe.
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