Constraining inflationary magnetogenesis and reheating via GWs in light of PTA data

Utilizing the bounds on primordial magnetic fields (PMFs), their contributions to secondary gravitational waves (GWs) and the results from the pulsar timing arrays (PTAs), we arrive at constraints on the epoch of reheating. We find that the combined spectral density of primary and secondary GWs (generated by the PMFs) can, in general, be described as a broken power law with five different indices. We show that the PMFs that have a blue tilt and satisfy the other observational constraints can generate secondary GWs of strengths suggested by the PTA data.
Comment: 14 pages(8+6); 4 figures