Calibrating Mg ii-based Black Hole Mass Estimators with Hβ Reverberation Measurements

• Published in: The Astrophysical journal Vol. 875; no. 1; pp. 50 - 66
• Main Authors: Bahk, Hyeonguk, Woo, Jong-Hak, Park, Daeseong
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10.04.2019; IOP Publishing
• Subjects: Active galactic nuclei; Astrophysics; Black holes; Bolometers; Calibration; Digital mapping; Emission lines; Estimators; galaxies: active; galaxies: nuclei; Luminosity; methods: statistical; Photoionization; quasars: supermassive black holes; Red shift; Reverberation; Sky surveys (astronomy)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ab100d

We present the new calibration of black hole mass ( ) estimators based on the Mg ii λ2798 broad emission line using the Hβ reverberation-mapped (RM) sample of 31 active galactic nuclei (AGNs) that have high-quality UV spectra. The updated and enlarged sample at redshift z < 0.16 covers a large dynamic range in (i.e., ) and bolometric luminosity (i.e., erg s−1). We also investigate the mass estimators by adding a sample from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, which consists of 24 AGNs at a higher redshift range, z = 0.36-0.89. We determine the line width of the Mg ii line using FWHM or line dispersion ( line), which are respectively used for the recipe. Comparing with the Hβ reverberation masses, we provide several calibrations for the Mg ii-based mass, the best of which is consistent with the virial assumption and photoionization expectation (i.e., and ). The derived based the Mg ii estimator is consistent with the Hβ reverberation mass within a factor of 2.