The structure of the Mg II broad line emitting region in Type 1 AGNs

Abstract

We investigate the structure of the Mg II broad line emission region in a sample of 284 Type 1 active galactic nuclei (AGNs), through comparing the kinematical parameters of the broad Mg II and broad H$\beta$ lines. We found that the Mg II emitting region has more complex kinematics than the H$\beta$ one. It seems that the \ion{Mg}{ii} broad line originates from two subregions: one which contributes to the line core, which is probably virialized, and the other, 'fountain-like' emitting region, with outflows-inflows nearly orthogonal to the disc, which become suppressed with stronger gravitational influence. This subregion mostly contributes to the emission of the Mg II broad line wings. The kinematics of the Mg II core emitting region is similar to that of the H$\beta$ broad line region (seems to be virialized), and therefore the Full Width at Half Maximum (FWHM) of Mg II still can be used for the black hole (BH) mass estimation in the case where the Mg II core component is dominant. However, one should be careful with using the \ion{Mg}{ii} broad line for the BH mass estimation in the case of very large widths (FWHM$>$ 6000 km s${}^{-1}$) and/or in the case of strong blue asymmetry.

accepted in MNRAS

References in corpus (7)

• Fe II Emission in 14 Low-Redshift Quasars: I - Observations
• The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-Line Light Curves
• Broad-line Balmer Decrements in Blue Active Galactic Nuclei
• Correcting CIV-Based Virial Black Hole Masses
• Hbeta Profiles in Quasars: Evidence for an Intermediate-line Region
• An Improved Method for Using MgII to Estimate Black Hole Masses in Active Galactic Nuclei
• The optical vs. mid-infrared spectral properties of 82 Type 1 AGNs: coevolution of AGN and starburst

Cited by in corpus (5)

• Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation
• The peculiar emission line spectra of core-Extremely Red BOSS Quasars at $z\sim$2-3: orientation and/or evolution?
• Caltech-NRAO Stripe 82 Survey (CNSS). IV. The Birth of Radio-loud Quasar 013815+00
• Estimating supermassive black hole masses in AGNs using polarization of broad MgII, H$\alpha$ and H$\beta$ lines
• Line shapes in narrow-line Seyfert 1 galaxies: a tracer of physical properties?