Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/36673
Title: QUASI-PERIODIC OSCILLATIONS AND BROADBAND VARIABILITY IN SHORT MAGNETAR BURSTS
Authors: Huppenkothen, D.
Watts, A. L.
Uttley, P.
van der Horst, A. J.
van der Klis, M.
Kouveliotou, C.
Göğüş, E.
Granot, J.
Vaughan, Simon Allan
Finger, M. H.
First Published: 17-Apr-2013
Publisher: IOP Publishing, American Astronomical Society
Citation: The Astrophysical Journal, 2013, 768 (1), pp. 87-87
Abstract: The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to search for QPOs, such analysis is seriously data limited. We set out a procedure for doing QPO searches in the far more numerous, short, less energetic magnetar bursts. The short, transient nature of these bursts requires the implementation of sophisticated statistical techniques to make reliable inferences. Using Bayesian statistics, we model the periodogram as a combination of red noise at low frequencies and white noise at high frequencies, which we show is a conservative approach to the problem. We use empirical models to make inferences about the potential signature of periodic and QPOs at these frequencies. We compare our method with previously used techniques and find that although it is on the whole more conservative, it is also more reliable in ruling out false positives. We illustrate our Bayesian method by applying it to a sample of 27 bursts from the magnetar SGR J0501+4516 observed by the Fermi Gamma-ray Burst Monitor, and we find no evidence for the presence of QPOs in any of the bursts in the unbinned spectra, but do find a candidate detection in the binned spectra of one burst. However, whether this signal is due to a genuine quasi-periodic process, or can be attributed to unmodeled effects in the noise is at this point a matter of interpretation.
DOI Link: 10.1088/0004-637X/768/1/87
ISSN: 0004-637X
eISSN: 1538-4357
Links: http://iopscience.iop.org/article/10.1088/0004-637X/768/1/87/meta
http://hdl.handle.net/2381/36673
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2013. The American Astronomical Society. All rights reserved. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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