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A fast hybrid algorithm for exoplanetary transit searches

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journal contribution
posted on 24.10.2012, 09:06 by Collier Cameron A., T. A. Lister, K. Horne, D. Pollacco, R. A. Street, D. J. Christian, A. Fitzsimmons, F. P. Keenan, R. Ryans, R. G. West, J. Osborne, W. I. Clarkson, B. Enoch, C. A. Haswell, A. J. Norton, N. R. Parley, D. M. Wilson, A. Evans, C. Hellier, S. T. Hodgkin, J. Irwin, S. R. Kane, I. Skillen, P. J. Wheatley, F. Pont
We present a fast and efficient hybrid algorithm for selecting exoplanetary candidates from wide-field transit surveys. Our method is based on the widely used SysRem and Box Least-Squares (BLS) algorithms. Patterns of systematic error that are common to all stars on the frame are mapped and eliminated using the SysRem algorithm. The remaining systematic errors caused by spatially localized flat-fielding and other errors are quantified using a boxcar-smoothing method. We show that the dimensions of the search-parameter space can be reduced greatly by carrying out an initial BLS search on a coarse grid of reduced dimensions, followed by Newton–Raphson refinement of the transit parameters in the vicinity of the most significant solutions. We illustrate the method's operation by applying it to data from one field of the SuperWASP survey, comprising 2300 observations of 7840 stars brighter than V= 13.0. We identify 11 likely transit candidates. We reject stars that exhibit significant ellipsoidal variations caused indicative of a stellar-mass companion. We use colours and proper motions from the Two Micron All Sky Survey and USNO-B1.0 surveys to estimate the stellar parameters and the companion radius. We find that two stars showing unambiguous transit signals pass all these tests, and so qualify for detailed high-resolution spectroscopic follow-up.

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Citation

Monthly Notices of the Royal Astronomical Society, 2006, 373 (2), pp. 799-810

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Royal Astronomical Society (RAS)

issn

0035-8711

eissn

1365-2966

Copyright date

2006

Available date

24/10/2012

Publisher version

http://mnras.oxfordjournals.org/content/373/2/799

Language

en

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