A Bayesian method for detecting stellar flares

Pitkin, M. , Williams, D., Fletcher, L. and Grant, S.D.T. (2014) A Bayesian method for detecting stellar flares. Monthly Notices of the Royal Astronomical Society, 445(3), pp. 2268-2284. (doi:10.1093/mnras/stu1889)

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We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares in light curve data. We assume flares are described by a model in which there is a rapid rise with a half-Gaussian profile, followed by an exponential decay. Our signal model also contains a polynomial background model required to fit underlying light curve variations in the data, which could otherwise partially mimic a flare. We characterize the false alarm probability and efficiency of this method under the assumption that any unmodelled noise in the data is Gaussian, and compare it with a simpler thresholding method based on that used in Walkowicz et al. We find our method has a significant increase in detection efficiency for low signal-to-noise ratio (S/N) flares. For a conservative false alarm probability our method can detect 95% of flares with S/N less than ~20, as compared to S/N of ~25 for the simpler method. We also test how well the assumption of Gaussian noise holds by applying the method to a selection of ``quiet'' Kepler stars. As an example we have applied our method to a selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars with a total of 1873 flares after vetos have been applied. For these flares we have made preliminary characterisations of their durations and and signal-to-noise ratios.

Item Type:Articles
Additional Information:This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 the Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Glasgow Author(s) Enlighten ID:Williams, Mr Daniel and Fletcher, Professor Lyndsay and Pitkin, Dr Matthew
Authors: Pitkin, M., Williams, D., Fletcher, L., and Grant, S.D.T.
Subjects:Q Science > QA Mathematics > QA76 Computer software
Q Science > QB Astronomy
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Monthly Notices of the Royal Astronomical Society
Publisher:Oxford University Press
ISSN (Online):1365-2966
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Monthly Notices of the Royal Astronomical Society
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
624341Investigations in Gravitational RadiationSheila RowanScience & Technologies Facilities Council (STFC)ST/L000946/1S&E P&A - PHYSICS & ASTRONOMY
542081Rolling Programme in Solar and Plasma AstrophysicsLyndsay FletcherScience & Technologies Facilities Council (STFC)ST/I001808/1P&A - PHYSICS & ASTRONOMY
631581Consolidated grant in solar and astrophysical plasmasLyndsay FletcherScience & Technologies Facilities Council (STFC)ST/L000741/1S&E P&A - PHYSICS & ASTRONOMY
UNSPECIFIEDUNSPECIFIEDAutomated searches for stellar flares in Kepler dataMatthew PitkinRoyal Society of EdinburghUNSPECIFIEDS&E P&A - PHYSICS & ASTRONOMY