PI: Todd Boroson, NOAO, firstname.lastname@example.org
Address: NSSC, Box 26732, Tucson, AZ 85726-6732, USA
CoI: Michael Eracleous, The Pennsylvania State University
Title: A Systematic Search for the Dynamical Signature of Close Supermassive Binary Black Holes -- Continuation
Abstract: A sample of 87 low-redshift quasars, systematically extracted from the SDSS archive, show substantial (>1000 km s^-1) shifts of the peak of the H(beta) line from the systemic redshift. Theory predicts that up to 1/4 of these may be sub-parsec binary supermassive black holes in which the emission line gas is associated with the less massive black hole. We have begun a program to obtain new spectra of this sample to search for changes in the velocity offset that would support this explanation. Given a distribution of orbital parameters, such changes are predicted to be easily detectable in the majority of the objects that are attributable to this effect. The results of our survey will provide immediate constraints on models for black hole growth and will identify objects for further study. In 2010, we obtained spectra of 69 of the 87 objects in our sample. The continuation of the program will emphasize those that we have so far missed and the 18 that showed measurable or suspected velocity changes in their second epoch spectra. Additional observations for this project of some of the objects will be made with the HET and the MDM 2.4m, using the Co-I's institutional access and through a collaborator, respectively.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360