2009/12/20 by J. Fang, Jun Fang, L. Zhang +1
Physics and Astronomy · #Acceleration #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Azimuth #Caustic (mathematics) #Cherenkov Telescope Array #Cherenkov radiation #Classical mechanics #Detector #Fermi Gamma-ray Space Telescope #Field line #Light curve #Light field #Magnetic field #Magnetosphere #Optics #Photon #Physics #Pulsar #Pulsars and Gravitational Waves Research #Quantum mechanics #Radio Astronomy Observations and Technology #Telescope #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/709/2/605
published as Astrophys.J.709:605-610,2010 · A reference is corrected
arxiv created 2009/12/20 · openalex publication_date 2010/01/07 · arxiv updated 2014/11/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
The GeV light curve of a pulsar is an important probe to detect acceleration regions in its magnetosphere. Motivated by the recent reports on the observations of pulsars by the Fermi Large Area Telescope, we restudy the two-pole caustic model and revise it to investigate the properties of the light curves in the GeV band. In the revised model, although acceleration gaps can extend from the star surface to the light cylinder along near the last open field lines, the extension of the gaps along the azimuthal direction is limited because of photon–photon pair production process. In such gaps, high-energy photons are emitted uniformly and tangentially to the field lines but cannot be efficiently produced along these field lines where the distances to the null charge surface are larger than ∼0.9 times the distance of the light cylinder, and the effective azimuth extension of the gaps is about 230°. The model is applied to the four pulsars, Vela, PSR J1028-5819, PSR J0205+6449, and PSR J2021+3651, whose light curves obtained with Fermi have been recently released. The model is successful in reproducing the general feature of the light curves for the four pulsars, and the radial distances of the radio pulse for the four pulsars are estimated.