Finding Binary Quasars in SDSS

1
Finding Binary Quasars in SDSS
Visual Doubles and Mergers
Discussion
-- Binary or jet interaction? Radio jets can
affect the dynamics of the NLR and produce double
peaked O III, for example MKN 78 (Whittle et al
2005). We obtained VLA maps at 4 frequencies
for two of our radio-loud objects as well as
long-slit spectra of J151733 with the Keck
telescope (Rosario et al. 2009). Comparison of
the radio and optical data indicate that the
double peaked line profile corresponds to a
bipolar jet interaction rather than a binary AGN.
An important question is how many of our other
candidates involve complex NLR dynamics in a
single AGN as opposed to a true binary AGN. --
Binary fueling in mergers? Approximately 1 of
the broad-line AGN in our sample have double
peaked O III lines, and most are radio quiet
and unresolved in the SDSS images. This may be a
rough indication of the frequency of binary AGN
with spacings of a few kpc. This result
complements results for more widely spaced (30
kpc), optically resolved binary QSOs, which show
a frequency of about 0.1 of QSOs (Foreman et al
2008, and references therein). Foreman et al.
argue that this incidence of binary QSOs is less
than expected if fueling of both black holes in a
galaxy merger is commonplace. An incidence of 1
in 100 at closer spacing may suggest a greater
probability of fueling both BH at later stages of
the galactic merger.
References Foreman, G., Volonteri, M., Dotti, M.
2008, arXiv08121569 Komossa, S. 2006, Mem.
S.A.It., 77, 733 Rosario, D., Salviander, S.,
Shields, G., Taylor, D. 2009 Salviander et al.
2007, ApJ, 662, 131 Whittle, M. et al. 2005, AJ,
129, 104 Zhou, H. et al. 2004, ApJ, 604, L33
Acknowledgements We thank Karl Gebhardt for the
use of his automated spectrum fitting program.
G.S. gratefully acknowledges support from the
Jane and Roland Blumberg Centennial Professorship
in Astronomy. This work is based on data from
the Sloan Digital Sky Survey (http//www.sdss.org)
.