Results from the search for a stochastic gravitational wave background in the NANOGrav 12.5-year data set

Pulsar timing arrays are galactic-scale low-frequency gravitational wave observatories sensitive to the nanohertz frequency band. The primary source of gravitational radiation in this regime is expected to be a stochastic background, formed by a cosmic population of supermassive black hole binaries. We present the results obtained by analyzing the 12.5-year data release from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) including constraints on the putative source population. We also discuss advanced noise modeling techniques for individual millisecond pulsars in the NANOGrav dataset, which has improved our sensitivity.