Techniques for Profile Binning and Analysis of Eigenvector Composite Spectra: Comparing Hbeta and MgII 2800 as Virial Estimators
arXiv:1310.4361 · doi:10.1016/j.asr.2013.09.039
Abstract
We review the basic techniques for extracting information about quasar structure and kinematics from the broad emission lines in quasars. We consider which lines can most effectively serve as virial estimators of black hole mass. At low redshift the Balmer lines,particularly broad H beta, are the lines of choice. For redshifts greater than 0.7 - 0.8 one can follow H beta into the IR windows or find an H beta surrogate. We explain why UV CIV 1549 is not a safe virial estimator and how MgII 2800 serves as the best virial surrogate for H beta up to the highest redshift quasar known at z ~ 7. We show how spectral binning in a parameter space context (4DE1) makes possible a more effective comparison of H beta and MgII. It also helps to derive more accurate mass estimates from appropriately binned spectra and, finally, to map the dispersion in black hole mass and Eddington ratio across the quasar population. FWHM MgII is about 20% smaller than FWHM H beta in the majority of type 1 AGN requiring correction when comparing black hole mass estimates from these two lines. The 20% of sources showing narrowest FWHM H beta (< 4000 km/s) and strongest FeII (R_FeII >~ 1.0) emission (we call them bin A3-4 sources) do not show this FWHM difference and a blueshift detected in MgII for these sources suggests that FWHM H beta is the safer virial estimator for these extreme Eddington emitters.
Accepted for publication in Advances in Space Research
References in corpus (11)
- A luminous quasar at a redshift of z = 7.085
- Biases in Virial Black Hole Masses: An SDSS Perspective
- CIV 1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei
- Black-Hole Mass and Growth Rate at High Redshift
- The First Spectroscopically Resolved Sub-parsec Orbit of a Supermassive Binary Black Hole
- VLT/ISAAC Spectra of the Hbeta Region in Intermediate-Redshift Quasars III. Hbeta Broad Line Profile Analysis and Inferences about BLR Structure
- New Insights on the QSO Radio-Loud/Radio-Quiet Dichotomy: SDSS Spectra in the Context of the 4D Eigenvector1 Parameter Space
- VLT/ISAAC Spectra of the H-beta Region in Intermediate-Redshift Quasars II. Black Hole Mass and Eddington Ratio
- Reverberation and photoionization estimates of the Broad Line Region Radius in Low-z Quasars
- NGC 5548: The AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus
- Accretion onto Supermassive Black Holes in Quasars: Learning from Optical/UV Observations