Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-10-11
Astronomy and Astrophysics
Astrophysics
10 pages including 4 figures, submitted to ApJL, incorporates referee's comments
Scientific paper
10.1086/595746
We present a method for obtaining accurate black hole (BH) mass estimates from the MgII emission line in active galactic nuclei (AGNs). Employing the large database of AGN measurements from the Sloan Digital Sky Survey (SDSS) presented by Shen et al., we find that AGNs in the redshift range 0.3-0.9, for which a given object can have both H-beta and MgII line widths measured, display a modest but correctable discrepancy in MgII-based masses that correlates with the Eddington ratio. We use the SDSS database to estimate the probability distribution of the true (i.e., H-beta-based) mass given a measured MgII line width. These probability distributions are then applied to the SDSS measurements from Shen et al. across the entire MgII-accessible redshift range (0.3-2.2). We find that accounting for this residual correlation generally increases the dispersion of Eddington ratios by a small factor (~0.09 dex for the redshift and luminosity bins we consider). We continue to find that the intrinsic distribution of Eddington ratios for luminous AGNs is extremely narrow, 0.3-0.4 dex, as demonstrated by Kollmeier et al. Using the method we describe, MgII emission lines can be used with confidence to obtain BH mass estimates.
Kollmeier Juna A.
Onken Christopher A.
No associations
LandOfFree
An Improved Method for Using MgII to Estimate Black Hole Masses in Active Galactic Nuclei does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An Improved Method for Using MgII to Estimate Black Hole Masses in Active Galactic Nuclei, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An Improved Method for Using MgII to Estimate Black Hole Masses in Active Galactic Nuclei will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-448872