Constraining Cosmological Phase Transitions with the Parkes Pulsar Timing Array
Abstract
A cosmological firstorder phase transition is expected to produce a stochastic gravitational wave background. If the phase transition temperature is on the MeV scale, the power spectrum of the induced stochastic gravitational waves peaks around nanohertz frequencies, and can thus be probed with highprecision pulsar timing observations. We search for such a stochastic gravitational wave background with the latest data set of the Parkes Pulsar Timing Array. We find no evidence for a HellingsDowns spatial correlation as expected for a stochastic gravitational wave background. Therefore, we present constraints on firstorder phase transition model parameters. Our analysis shows that pulsar timing is particularly sensitive to the lowtemperature (T ∼1  100 MeV ) phase transition with a duration (β /H_{*})^{1}∼10^{2}−10^{1} and therefore can be used to constrain the dark and QCD phase transitions.
 Publication:

Physical Review Letters
 Pub Date:
 December 2021
 DOI:
 10.1103/PhysRevLett.127.251303
 arXiv:
 arXiv:2110.03096
 Bibcode:
 2021PhRvL.127y1303X
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Phenomenology
 EPrint:
 9 pages, 4 figures, 2 tables