1,740 research outputs found
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
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