Search for Stochastic Gravitational-Wave Background from Massive Gravity in the NANOGrav 12.5-Year Data Set

Understand

Gravitational waves offer a new window to probe the nature of gravity, including answering if the mediating particle, graviton, has a non-zero mass or not.

• Pulsar timing arrays measure stochastic gravitational wave background (SGWB) at $\sim1-100$~nanohertz.
• Recently, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration reported an uncorrelated common-spectrum process in their 12.5-year data set with no substantial evidence that the process comes from the SGWB predicted by general relativity.
• In this work, we explore the possibility of an SGWB from massive gravity in the data set and find that a massless graviton is preferred because of the relatively larger Bayes factor.