The first observation of optical pulsations from a soft gamma repeater : SGR 0501+4516
Dhillon, V. S., Marsh, T. R., Littlefair, S. P., Copperwheat, C. M., Hickman, R. D. G. (Richard D. G.), Kerry, P. (Paul), Levan, A. J., Rea, N., Savoury, C. D. J., Tanvir, Nial R., Turolla, R. and Wiersema, K.. (2011) The first observation of optical pulsations from a soft gamma repeater : SGR 0501+4516. Monthly Notices of the Royal Astronomical Society: Letters, Vol.416 (No.1). L16-L20. ISSN 1745-3925Full text not available from this repository.
Official URL: http://dx.doi.org/10.1111/j.1745-3933.2011.01088.x
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 a 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 per cent, approximately a factor of 2 greater than in the X-rays. Our results find a natural explanation within the context of the magnetar model for SGRs.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Neutron stars, Pulsars, Stellar oscillations|
|Journal or Publication Title:||Monthly Notices of the Royal Astronomical Society: Letters|
|Official Date:||September 2011|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Science and Technology Facilities Council (Great Britain) (STFC)|
Alpar M. A., 2001, ApJ, 554, 1245
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