SEARCH FOR GAMMA-RAY EMISSION FROM MAGNETARS WITH THE FERMI LARGE AREA TELESCOPE
Abdo, A. A. AA ; Ackermann, M. ; Ajello, M. ; Giommi, P. ;
Dec - 2010
ISSN : 2041-8205 ;
journal : The Astrophysical Journal

Issue : 1
type: Article Journal

Abstract
We report on the search for 0.1-10 GeV emission from magnetars in 17 months of Fermi  Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently known magnetars is found. The most stringent upper limits to date on their persistent emission in the Fermi energy range are estimated between <1012and1010 erg s1 cm2, depending on the source. We also searched for gamma-ray pulsations and possible outbursts, also with no significant detection. The upper limits derived support the presence of a cutoff at an energy below a few MeV in the persistent emission of magnetars. They also show the likely need for a revision of current models of outer-gap emission from strongly magnetized pulsars, which, in some realizations, predict detectable GeV emission from magnetars at flux levels exceeding the upper limits identified here using the Fermi-LAT observations.

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