تقرير
Mode change of a gamma-ray pulsar, PSR J2021+4026
| العنوان: | Mode change of a gamma-ray pulsar, PSR J2021+4026 |
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| المؤلفون: | Zhao, J., Ng, C. W., Lin, L. C. C., Takata, J., Cai, Y., Hu, C. P., Yen, D. C. C., Tam, P. H. T., Hui, C. Y., Kong, A. K. H., Cheng, K. S. |
| سنة النشر: | 2017 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena |
| الوصف: | A glitch of a pulsar is known as a sudden increase in the spin frequency and spin-down rate (frequency time derivative), and it can be caused by a sudden rel\ ease of the stress built up in the solid crust of the star or pinned vortices in the superfluid interior. PSR J2021+4026 is the first pulsar that shows a significant change in the gamma-ray flux and pulse profile at the glitch that occurred around 2011 October 16. We report the results of timing and spectral analysis of PSR~J2021+4026 using $\sim$ 8~yr Fermi-LAT data. We find that the pulsar stayed at a high spin-down rate ($\sim 4\%$ higher than the pre-glitch value) and a low gamma-ray state ($\sim 18\%$ lower) for about 3~yr after the glitch. Around 2014 December, the spin-down rate and gamma-ray flux gradually returned to pre-glitch values within a time scale of a few months. The phase-resolved spectra and pulse profiles after the relaxation are also consistent with those before the glitch. The observed long-term evolution of the spin-down rate and the gamma-ray flux indicates that the glitch triggered a mode change in the global magnetosphere. We speculate that the glitch changed the local magnetic field structure around the polar cap and/or the inclination angle of the dipole axis, leading to a change in the electric current circulating in the magnetosphere. Comment: 23 pages, 6 figures. Accepted for publication in ApJ |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.3847/1538-4357/aa74d8 |
| URL الوصول: | http://arxiv.org/abs/1706.00236 |
| رقم الأكسشن: | edsarx.1706.00236 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.3847/1538-4357/aa74d8 |
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