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arXiv · 0810.0008

Discovery of High-Energy Gamma-Ray Pulsations from PSR J2021+3651 with AGILE

J. P. Halpern·F. Camilo·A. Giuliani·E. V. Gotthelf·M. A. McLaughlin·R. Mukherjee·A. Pellizzoni·S. M. Ransom·M. S. E. Roberts·M. Tavani
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Abstract

Discovered after the end of the Compton Gamma-Ray Observatory mission, the radio pulsar PSR J2021+3651 was long considered a likely counterpart of the high-energy gamma-ray source 2CG 075+00 = 3EG J2021+3716 = GeV J2020+3658, but it could not be confirmed due to the lack of a contemporaneous radio pulsar ephemeris to fold the sparse, archival gamma-ray photons. Here, we report the discovery of gamma-ray pulsations from PSR J2021+3651 in the 100-1500 MeV range using data from the AGILE satellite gathered over 8 months, folded on a densely sampled, contemporaneous radio ephemeris obtained for this purpose at the Green Bank Telescope. The gamma-ray pulse consists of two sharp peaks separated by 0.47+/-0.01 cycles. The single radio pulse leads the first gamma-ray peak by 0.165+/-0.010 cycles. These properties are similar to those of other gamma-ray pulsars, and the phase relationship of the peaks can be interpreted in the context of the outer-gap accelerator model for gamma-ray emission. Pulse-phase resolved images show that there is only one dominant source, AGL J2020.5+3653 = PSR J2021+3651 in the region previously containing confused sources 3EG J2021+3716 and 3EG J2016+3657.

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J. P. Halpern, F. Camilo, A. Giuliani, E. V. Gotthelf, M. A. McLaughlin, R. Mukherjee, A. Pellizzoni, S. M. Ransom, M. S. E. Roberts, M. Tavani. 2008-09-30. Discovery of High-Energy Gamma-Ray Pulsations from PSR J2021+3651 with AGILE. https://doi.org/10.1086/594117

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