The Leonard E Parker Center for Gravitation, Cosmology and Astrophysics holds frequent seminars on a broad range of ongoing cosmology and gravitation research topics. Unless otherwise noted, seminars are on Friday afternoons at 1:00 PM in KIRC 2175; there is a gathering for a brown bag lunch at 12:30.

PTA searches for Gravitational Waves: Astrophysics with non-detections
Dr. Justin Ellis,

Pulsar timing arrays (PTAs) offer a unique opportunity to detect low frequency gravitational waves (GWs) in the near future. In this frequency band, the expected source of GWs are Supermassive Black Hole Binaries (SMBHBs) and they will most likely form in an ensemble creating a stochastic GW background with the possibility of a few nearby/massive sources that will be individually resolvable. After timing an array of pulsars for up to 9 years, we have not yet made a detection; however, our constraints on the gravitational wave background and single GW sources are beginning to inform astrophysical models of binary black hole evolution. In this talk I will present recent work from the NANOGrav collaboration that has allowed us to place constraints on the astrophysical scenarios in which SHMBHBs evolve. Furthermore, I will discuss PTAs sensitivity to newly discovered SMBHB candidates and lay out scenarios for increasing chances of detection of both stochastic and single GW sources.