Mysterious stochastic processes in pulsar timing array data sets - Boris Goncharov

Pulsar timing array collaborations perform decade-long measurements of pulse arrival times from millisecond pulsars with the primary goal to detect nanohertz stochastic gravitational-wave background from supermassive black hole binaries. The background will manifest as pulsar-correlated noise with a power-law "red" spectrum of timing residuals. The pulsars, the interstellar medium, the uncertainty in the position of the Solar System barycentre, and other factors introduce various noise. Some of this noise also has a red spectrum. Following a short overview of signals and noise in pulsar timing arrays, I will describe new sources of noise that we discovered during the analysis of the Second Data Release of the Parkes Pulsar Timing Array (PPTA DR2). Additionally, the recent paper by the NANOGrav collaboration has reported strong evidence for "common" red noise and minor evidence for spatial correlations expected from the stochastic background. We are seeing the similar picture in PPTA DR2, I will provide more details in the talk.