Bulletin of the American Physical Society
APS April Meeting 2023
Volume 68, Number 6
Minneapolis, Minnesota (Apr 15-18)
Virtual (Apr 24-26); Time Zone: Central Time
Session N02: Cecilia Payne-Gaposchkin Doctoral Thesis Award in Astrophysics
1:30 PM–3:18 PM,
Monday, April 17, 2023
Room: MG Salon A - 3rd Floor
Sponsoring Unit: DAP
Chair: Amy Furniss, California State University, East Bay
Abstract: N02.00003 : Bayesian Methods for Multi-Messenger Analysis of Supermassive Black Hole Binaries: Pulsars and Quasars and Gravitational Waves, Oh My!
2:42 PM–3:18 PM
Caitlin A Witt
Caitlin A Witt
By using electromagnetic observations to identify an SMBHB candidate, we gain numerous pieces of information that also define the source’s GW emission. I developed the first multi-messenger techniques used by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), and applied them to a well-known SMBHB candidate, 3C 66B. We placed the lowest chirp mass limit to date on an SMBHB within 3C 66B of M < 1.65 × 109M?. and showed that multi-messenger techniques can lead to dramatic improvements over “blind” searches.
Next, I analyzed the capabilities of Bayesian methods to search for electromagnetic signatures of these binaries in simulated time-domain data sets. I developed a Bayesian model selection technique to identify periodicities induced into a quasar light curve by the orbital motion of an SMBHB from within intrinsic red noise, and discovered that future surveys like LSST will identify more robust SMBHB candidates than current surveys.
Finally, I presented the results of searches for bright continuous GWs (CWs) from individual SMBHBs in NANOGrav’s 12.5-year data set. In this work, I searched for CWs alongside a common red noise process (which could be the first signs of an emerging stochastic GW background) for the first time in real PTA data, and developed necessary data-handling techniques which will be critical for the detection of a CW, which may come soon after the eventual detection of the GW background.
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