Three Millisecond Pulsars in Fermi LAT Unassociated Bright Sources
Abdo, A. A.; Camilo, F.; Çelik, Ö.; Cheung, C. C.; Gehrels, N.; Grove, J. E.; Guillemot, L.; Gwon, C.; Harding, A. K.; Kerr, M.; Michelson, P. F.; Parent, D.; Ransom, S. M.; Ray, P. S.; Romani, R. W.; Saz Parkinson, P. M.; Smith, D. A.; Thompson, D. J.; Wolff, M. T.; Wood, K. S.; Ziegler, M.; Ferrara, E. C.; Kramer, M.; Johnston, S.; Theureau, G.; Lyne, A. G.; Stappers, B. W.; Freire, P. C. C.; Keith, M.; Weltevrede, P.; Donato, D.; Cognard, I.; Desvignes, G.; DeCesar, M. E.; Roberts, M. S. E.; Pennucci, T.
United States, France, United Kingdom, Germany, Australia
Abstract
We searched for radio pulsars in 25 of the non-variable, unassociated sources in the Fermi LAT Bright Source List with the Green Bank Telescope at 820 MHz. We report the discovery of three radio and γ-ray millisecond pulsars (MSPs) from a high Galactic latitude subset of these sources. All of the pulsars are in binary systems, which would have made them virtually impossible to detect in blind γ-ray pulsation searches. They seem to be relatively normal, nearby (<=2 kpc) MSPs. These observations, in combination with the Fermi detection of γ-rays from other known radio MSPs, imply that most, if not all, radio MSPs are efficient γ-ray producers. The γ-ray spectra of the pulsars are power law in nature with exponential cutoffs at a few GeV, as has been found with most other pulsars. The MSPs have all been detected as X-ray point sources. Their soft X-ray luminosities of ~1030-1031 erg s-1 are typical of the rare radio MSPs seen in X-rays.