Fermi pulsar revolution

2009 has been an extraordinary year for gamma-ray pulsar astronomy and 2010 promises to be equally good. Not only have we registered an extraordinary increase in the number of pulsars detected in gamma rays, but we have also witnessed the birth of new sub-families: first of all, the radio-quiet gamma pulsars and later an ever growing number of millisecond pulsars, a real surprise. We started with a sample of 7 gamma-ray emitting neutron stars (6 radio pulsars and Geminga) and now the Fermi-LAT harvest encompasses 24 "Geminga-like" new gamma-ray pulsars, a dozen millisecond pulsars and about thirty radio pulsars. Moreover, radio searches targeted to LAT unidentified sources yielded 18 new radio millisecond pulsars, several of which have been already detected also in gamma rays. Thus, currently the family of gamma-ray emitting neutron stars seems to be evenly divided between classical radio pulsars, millisecond pulsars and radio quiet neutron stars.Comment: High Time Resolution Astrophysics IV - The Era of Extremely Large Telescopes-HTRA-IV Agios Nikolaos, Crete, Greece May 5-7 2010 to be published in Po

Pulsar Counterparts of Gamma-Ray Sources

The EGRET catalogue of unidentified X-ray sources has more objects along the galactic disk than at high galactic latitude, where identifications are comparatively easier. On the other hand, the Egret/GRO mission has already identified several known radio pulsars as gamma-ray sources as well as discovering Geminga's nature as a pulsar. If Geminga is not a unique case, as it is very likely not to be, than other galactic sources could, in fact, be radio quiet isolated neutron stars. For these, the identification work is extremely difficult and should anyway start from high resolution X-ray/optical data.Comment: 6 pages, LaTeX, macro aipproc.st

Detection of an X-ray Pulsation for the Gamma-ray Pulsar Centered in CTA 1

We report the detection of X-ray pulsations with a period of ~315.87 ms from the 2009 XMM-Newton observation for the radio-quiet gamma-ray pulsar, LAT PSR J0007+7303, centered in the supernova remnant CTA 1. The detected pulsed period is consistent with the gamma-ray periodicity at the same epoch found with the Fermi Gamma-ray Space Telescope. The broader sinusoidal structure in the folded light curve of the X-ray emission is dissimilar to that of the gamma-ray emission, and the phase of the peak is about 0.5 shifting from the peak in the gamma-ray bands, indicating that the main component of the X-rays originates from different sites of the pulsar. We conclude that the main component of the X-ray pulsation is contributed by the thermal emission from the neutron star. Although with a significantly different characteristic age, PSR~J0007+7303 is similar to Geminga in emission properties of X-rays and gamma-rays; this makes PSR J0007+7303 the second radio-quiet gamma-ray pulsar with detected X-ray pulsations after Geminga.Comment: 7 pages, 4 figures and 1 table; accepted by ApJ