Speaker
Description
The NANOGrav and Parkes pulsar timing array (PTA) collaborations have recently reported strong evidence for a new stochastic process affecting the pulsar timing residuals in their respective most recent data sets, raising the hope that they have thus caught the first glimpse of a stochastic gravitational-wave background at nanohertz frequencies. In this talk, I will review the properties of the detected signal and discuss its interpretation in terms of gravitational waves emitted by a network of cosmic strings in the early Universe. As I will demonstrate, both stable and metastable cosmic strings lead to a viable explanation of the signal across large regions in parameter space. This result serves as a powerful illustration of how PTA observations provide us with a unique chance to probe elementary particle physics at very high energies all the way up to the scale of grand unification.
