The NANOGrav 12.5-year Data Set: Search for Gravitational Wave Memory

Understand

We present the results of a Bayesian search for gravitational wave (GW) memory in the NANOGrav 12.5-yr data set.

• We find no convincing evidence for any gravitational wave memory signals in this data set (Bayes factor = 2.8).
• As such, we go on to place upper limits on the strain amplitude of GW memory events as a function of sky location and event epoch.
• These upper limits are computed using a signal model that assumes the existence of a common, spatially uncorrelated red noise in addition to a GW memory signal.