503 research outputs found
Latest results on gamma-ray pulsars with Fermi
The Fermi Large Area Telescope (LAT) has been scanning the gamma-ray sky
since 2008. The number of pulsars detected by the LAT now exceeds 200, making
them by far the largest class of Galactic gamma-ray emitters. I discuss some of
the latest pulsar discoveries made by the LAT, in particular those made since
the release of the Pass 8 data.Comment: 5 pages, to appear in Il Nuovo Cimento
Fermi-LAT searches for gamma-ray pulsars
The Large Area Telescope (LAT) on the Fermi satellite is the first gamma-ray
instrument to discover pulsars directly via their gamma-ray emission. Roughly
one third of the 117 gamma-ray pulsars detected by the LAT in its first three
years were discovered in blind searches of gamma-ray data and most of these are
undetectable with current radio telescopes. I review some of the key LAT
results and highlight the specific challenges faced in gamma-ray (compared to
radio) searches, most of which stem from the long, sparse data sets and the
broad, energy-dependent point-spread function (PSF) of the LAT. I discuss some
ongoing LAT searches for gamma-ray millisecond pulsars (MSPs) and gamma-ray
pulsars around the Galactic Center. Finally, I outline the prospects for future
gamma-ray pulsar discoveries as the LAT enters its extended mission phase,
including advantages of a possible modification of the LAT observing profile.Comment: Proceedings of the IAU Symposium 291, IAU XXVIII General Assembly,
Beijing, China, August 2012: "Neutron Stars and Pulsars: Challenges and
Opportunities after 80 years", Editor: Joeri van Leeuwen. To be published by
Cambridge University Press. 6 page
Milagro Search for Very High Energy Emission from Gamma-Ray Bursts in the Swift Era
The recently launched Swift satellite is providing an unprecedented number of
rapid and accurate Gamma-Ray Burst (GRB) localizations, facilitating a flurry
of follow-up observations by a large number of telescopes at many different
wavelengths. The Very High Energy (VHE, >100 GeV) regime has so far been
relatively unexplored. Milagro is a wide field of view (2 sr) and high duty
cycle (> 90%) ground-based gamma-ray telescope which employs a water Cherenkov
detector to monitor the northern sky almost continuously in the 100 GeV to 100
TeV energy range. We have searched the Milagro data for emission from the most
recent GRBs identified within our field of view. These include three Swift
bursts which also display late-time X-ray flares. We have searched for emission
coincident with these flares. No significant detection was made. A 99%
confidence upper limit is provided for each of the GRBs, as well as the flares.Comment: To be published in AIP Conference Proceedings "Gamma Ray Bursts in
the Swift Era," Nov. 29 - Dec. 2, 2005, Washington, D
Gamma-ray pulsars in the Fermi LAT era
Observations over the past two years with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope have led to a tenfold increase in the number of known γ-ray pulsars. Roughly one third of this population consists of young radio-loud pulsars, one third are radio-quiet pulsars discovered in blind searches of LAT data, and one third are γ-ray millisecond pulsars (MSPs). In this paper I discuss what we have learned about these three populations, as well as prospects for further discoveries
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