Pulsed Gamma-Rays from PSR J2021+3651 with the Fermi Large Area Telescope [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2009. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 1,059-1,066 : digital, PDF file
- Additional Creators:
- United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information
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- Free-to-read Unrestricted online access
- In this paper, we report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 ± 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 ± 0.004 ± 0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56 ± 3 ± 11) × 10<sup>–8</sup> cm<sup>–2</sup> s<sup>–1</sup>. The photon spectrum is well described by an exponentially cut-off power law of the form dF/dE = kE<sup>–Γ</sup>e<sup>(–E/E<sub>c</sub>)</sup>, where the energy E is expressed in GeV. The photon index is Γ = 1.5 ± 0.1 ± 0.1 and the exponential cut-off is E<sub>c</sub> = 2.4 ± 0.3 ± 0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is < 10% of the pulsed emission at the 95% confidence level. Radio polarization measurements yield a rotation measure of RM = 524 ± 4 rad m<sup>–2</sup> but a poorly constrained magnetic geometry. Re-analysis of Chandra X-ray Observatory data enhanced the significance of the weak X-ray pulsations, and the first peak is roughly phase aligned with the first gamma-ray peak. We discuss the emission region and beaming geometry based on the shape and spectrum of the gamma-ray light curve combined with radio and X-ray measurements, and the implications for the pulsar distance. Finally, gamma-ray emission from the polar cap region seems unlikely for this pulsar.
- Published through SciTech Connect., 07/08/2009., Astrophysical Journal 700 2 ISSN 0004-637X AM, Abdo, A.; Ackermann, M.; Ajello, M.; Atwood, W.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Battelino, M.; Baughman, B.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E.; Bogaert, G.; Borgland, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T.; Caliandro, G.; Cameron, R.; Camilo, F.; Caraveo, P.; et al., and SLAC National Accelerator Lab., Menlo Park, CA (United States)
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