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dc.contributor.authorLittlefair, S.~P.
dc.contributor.authorBurningham, B.
dc.contributor.authorHelling, Ch.
dc.identifier.citationLittlefair , S P , Burningham , B & Helling , C 2017 , ' Robust detection of quasi-periodic variability : HAWK-I mini survey of late-T dwarfs ' , Monthly Notices of the Royal Astronomical Society , vol. 466 , no. 4 , pp. 4250-4258 .
dc.identifier.otherPURE: 256402014
dc.identifier.otherPURE UUID: af8871a5-7d50-47c5-855a-e5bab8d6cd9f
dc.identifier.otherBibtex: urn:70db061d614d1d824dea3463d5b33cbf
dc.identifier.otherWOS: 000402849400034
dc.identifier.otherScopus: 85039453997
dc.descriptionSPL is supported by STFC grant ST/M001350/1. BB acknowledges financial support from the European Commision in the form of a Marie Curie International Outgoing Fellowship (PIOF-GA-2013-629435). Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 090.C-0721. ChH highlights financial support of the European Community under the FP7 by the ERC starting grant 257431.en
dc.description.abstractWe present HAWK-I J-band light curves of five late-type T dwarfs (T6.5–T7.5) with a typical duration of 4 h and investigate the evidence for quasi-periodic photometric variability on intra-night time-scales. Our photometry reaches precisions in the range 7–20 mmag, after removing instrumental systematics that correlate with sky background, seeing and airmass. Based upon a Lomb–Scargle periodogram analysis, the latest object in the sample – ULAS J2321 (T7.5) – appears to show quasi-periodic variability with a period of 1.64 h and an amplitude of 3 mmag. Given the low amplitude of variability and presence of systematics in our light curves, we discuss a Bayesian approach to robustly determine if quasi-periodic variability is present in a light curve affected by red noise. Using this approach, we conclude that the evidence for quasi-periodic variability in ULAS J2321 is not significant. As a result, we suggest that studies which identify quasi-periodic variables using the false alarm probability from a Lomb–Scargle periodogram are likely to overestimate the number of variable objects, even if field stars are used to set a higher false alarm probability threshold. Instead we argue that a hybrid approach combining a false alarm probability cut, followed by Bayesian model selection, is necessary for robust identification of quasi-periodic variability in light curves with red noise.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.rightsCopyright © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. his work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at:
dc.subjectBrown dwarfsen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleRobust detection of quasi-periodic variability : HAWK-I mini survey of late-T dwarfsen
dc.typeJournal articleen
dc.contributor.sponsorEuropean Research Councilen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. St Andrews Centre for Exoplanet Scienceen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden
dc.identifier.grantnumber257431 257431en

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