Timing of pulsars in the globular cluster omega centauri

We present the timing of the first five millisecond pulsars disco v ered in the globular cluster Omega Centauri and the disco v ery of a pulsar with a spin period of 3.68 ms. With a timing baseline of similar to 3.5 yr we are able to measure the deri v ati ve of the spin frequency (nu) 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 ne gativ e accelerations, which are in tension with the minimum acceleration predicted by analytical models. We searched for pulsed gamma-ray signals using 14.3 yr of data from the Fermi Large Area Telescope. Although we found no evidence for gamma-ray pulsations, PSRs J1326-4728A, B, C, and E are associated with X-ray sources. This suggests that the observed gamma-ray emission from Omega Centauri is likely caused by the emission of the ensemble of MSPs. Finally, the linearly polarized emission from PSR J1326 -4728A yields a rotation measure of -18 +/- 8 rad m(-2).