The first observation of optical pulsations from a soft gamma repeater: SGR 0501+4516
| Autor: | Dhillon, V. S., Marsh, T. R., Littlefair, S. P., Copperwheat, C. M., Hickman, R. D. G., Kerry, P., Levan, A. J., Rea, N., Savoury, C. D. J., Tanvir, N. R., Turolla, R., Wiersema, K. |
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| Rok vydání: | 2011 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1111/j.1745-3933.2011.01088.x |
| Popis: | We present high-speed optical photometry of the soft gamma repeater SGR 0501+4516, obtained with ULTRACAM on two consecutive nights approximately 4 months after the source was discovered via its gamma-ray bursts. We detect SGR 0501+4516 at a magnitude of i' = 24.4+/-0.1. We present the first measurement of optical pulsations from an SGR, deriving a period of 5.7622+/-0.0003 s, in excellent agreement with the X-ray spin period of the neutron star. We compare the morphologies of the optical pulse profile with the X-ray and infrared pulse profiles; we find that the optical, infrared and harder X-rays share similar double-peaked morphologies, but the softer X-rays exhibit only a single-peaked morphology, indicative of a different origin. The optical pulsations appear to be in phase with the X-ray pulsations and exhibit a root-mean-square pulsed fraction of 52+/-7%, approximately a factor of two greater than in the X-rays. Our results find a natural explanation within the context of the magnetar model for SGRs. Comment: 5 pages, 3 figures, accepted for publication in MNRAS Letters |
| Databáze: | arXiv |
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