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The likely detection of pulsed high-energy gamma-ray emission from millisecond pulsar PSR J0218+4232

L. Kuiper·W. Hermsen·F. Verbunt·D. J. Thompson·I. H. Stairs·A. G. Lyne·M. S. Strickman·G. Cusumano
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Abstract

We report circumstantial evidence for the first detection of pulsed high-energy gamma-ray emission from a millisecond pulsar, PSR J0218+4232, using data collected with the Energetic Gamma Ray Experiment (EGRET) on board the Compton Gamma Ray Observatory (CGRO). The EGRET source 3EG J0222+4253 is shown to be spatially consistent with PSR J0218+4232 for the energy range 100 - 300 MeV. Above 1 GeV the nearby BL Lac 3C 66A is the evident counterpart, and between 300 MeV and 1 GeV both sources contribute to the gamma-ray excess. Folding the 100-1000 MeV photons with an accurate radio ephemeris of PSR J0218+4232 yields a double peaked pulse profile with a ~3.5 sigma modulation significance and with a peak separation of ~0.45 similar to the 0.1-10 keV pulse profile.

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L. Kuiper, W. Hermsen, F. Verbunt, D. J. Thompson, I. H. Stairs, A. G. Lyne, M. S. Strickman, G. Cusumano. 2000-05-16. The likely detection of pulsed high-energy gamma-ray emission from millisecond pulsar PSR J0218+4232. https://arxiv.org/abs/astro-ph/0005338

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