Publication Date:
2013-04-26
Description:
We discuss a possible scenario for radiation mechanism of pulsed GeV -rays from magnetars. The magnetars have shown frequent X-ray bursts, which would be triggered by crust fractures and could release the energy of order of E tot ~ 10 41–42 erg. If the location of the crust cracking of the magnetic field is close to the magnetic pole, part of the released energy may excite the Alfv $\acute{\rm e}$ n wave that can propagate into outer magnetosphere. The oscillation of the magnetic field induces the available potential drop p ~ 10 15 V, which can accelerate the electrons and/or positrons to the Lorentz factor ~ 10 7 in the outer magnetosphere. The curvature radiation process at outer magnetosphere can produce GeV -rays. If the radiation process is occurred above r ~ 5 x 10 7 cm from the stellar surface, the emitted GeV -rays can escape from the pair-creation process with the X-rays and/or the magnetic field. The expected luminosity of the GeV emissions is order of L ≤ 10 35 erg s –1 , and the radiation process will last for a temporal scale of years. The expected pulse profiles have a broad shape with sometimes sharp peaks. We apply the model to anomalous X-ray pulsar 1E 2259+586.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
Permalink