We present the timing of the first five millisecond pulsars discovered in the globular cluster Omega Centauri and the discovery of a pulsar with a spin period of 3.68 ms. With a timing baseline of ∼3.5 yr we are able to measure the derivative of the spin frequency (ν˙) for the first five pulsars. Upper limits on the pulsar line-of-sight acceleration are estimated and compared with predictions based on analytical models of the cluster. We find that PSRs J1326−4728B and D show large negative accelerations, which are in tension with the minimum acceleration predicted by analytical models. We searched for pulsed γ-ray signals using 14.3 yr of data from the Fermi Large Area Telescope. Although we found no evidence for γ-ray pulsations, PSRs~J1326−4728A, B, C and E are associated with X-ray sources. This suggests that the observed γ-ray emission from Omega Centauri is likely caused by the emission of the ensemble of MSPs. Finally, the linearly polarised emission from PSR J1326−4728A yields a rotation measure of −18±8 rad m−2.
@article{arxiv.2303.02834,
title = {Timing of Pulsars in the Globular Cluster Omega Centauri},
author = {S. Dai and S. Johnston and M. Kerr and J. Berteaud and B. Bhattacharyya and F. Camilo and E. Keane},
journal= {arXiv preprint arXiv:2303.02834},
year = {2023}
}