Rochester Institute of Technology

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Observing Supermassive Black Hole Binaries
  • Speaker: TingTing Liu
  • Start Time:
  • End Time:
  • Location: 74-2050
  • Type: Lunch Talk

Observing Supermassive Black Hole Binaries

Supermassive black hole binaries (SMBHBs) should be common products of the hierarchical growth of galaxies and the loudest expected sources of low-frequency gravitational waves. Periodic quasar variability has been predicted as an observational signature of SMBHBs, due to modulated mass accretion or relativistic Doppler boosting. We have conducted a systematic search for periodically varying quasars in the Pan-STARRS1 Medium Deep Survey (PS1 MDS) and identified 26 candidates in a ~50 deg^2 sky area. We further extend the temporal baseline of observations via our imaging campaign with the Discovery Channel Telescope and the Las Cumbres Observatory network telescopes and reevaluate the candidates using a range of statistical criteria. We determine an upper limit of <0.6 SMBHBs per 1000 quasars out to z~2, in potential tension with previous work.  We also apply our method to the well-known periodic quasar and SMBHB candidate PG1302-102 using extended data from the All-sky Automated Survey for Supernovae and find that evidence for its periodicity has weakened over a baseline of ~15 years. 



I am starting a postdoc at the Leonard E. Parker Center for Gravitation, Cosmology and Astrophysics in the Department of Physics at the University of Wisconsin – Milwaukee. I recently completed my Ph.D. at the University of Maryland, where I also received my M.S. in Astronomy. I am interested in searching for supermassive black hole binaries and studying them using gravitational wave and electromagnetic observations.