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A deceleration search for magnetar pulsations in the X-ray plateaus of short GRBs
journal contributionposted on 2018-04-19, 10:05 authored by A. Rowlinson, A. Patruno, P. T. O'Brien
A newly formed magnetar has been proposed as the central engine of short GRBs to explain ongoing energy injection giving observed plateau phases in the X-ray light curves. These rapidly spinning magnetars may be capable of emitting pulsed emission comparable to known pulsars and magnetars. In this paper we show that, if present, a periodic signal would be detectable during the plateau phases observed using the Swift/X-Ray Telescope recording data in Window Timing mode. We conduct a targeted deceleration search for a periodic signal from a newly formed magnetar in 2 Swift short GRBs and rule out any periodic signals in the frequency band 10–285 Hz to ≈15–30 per cent rms. These results demonstrate that we would be able to detect pulsations from the magnetar central engine of short GRBs if they contribute to 15–30 per cent of the total emission. We consider these constraints in the context of the potential emission mechanisms. The non-detection is consistent with the emission being reprocessed in the surrounding environment or with the rotation axis being highly aligned with the observing angle. As the emission may be reprocessed, the expected periodic emission may only constitute a few per cent of the total emission and be undetectable in our observations. Applying this strategy to future observations of the plateau phases with more sensitive X-ray telescopes may lead to the detection of the periodic signal.
AP acknowledges support from a Netherlands Organization for Scientific Research (NWO) Vidi Fellowship. PTO would like to acknowledge funding from STFC. This work makes use of data supplied by the UK Swift Science Data Centre at the University of Leicester and the Swift satellite. Swift, launched in November 2004, is a NASA mission in partnership with the Italian Space Agency and the UK Space Agency. Swift is managed by NASA Goddard. Penn State University controls science and flight operations from the Mission Operations Center in University Park, Pennsylvania. Los Alamos National Laboratory provides gamma-ray imaging analysis.
CitationMonthly Notices of the Royal Astronomical Society, 2017, 472 (1), pp. 1152-1161 (10)
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
- VoR (Version of Record)
Published inMonthly Notices of the Royal Astronomical Society
PublisherOxford University Press (OUP), Royal Astronomical Society