J/PASP/128/G4502 False alarms in Kepler planet candidate cat. (Mullally+, 2016)
Identifying false alarms in the Kepler planet candidate catalog.
Mullally F., Coughlin J.L., Thompson S.E., Christiansen J., Burke C.,
Clarke B.D., Haas M.R.
<Publ. Astron. Soc. Pac., 128, part no 7, 4502-74502 (2016)>
=2016PASP..128g4502M 2016PASP..128g4502M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets
Keywords: methods: data analysis - planets and satellites: detection -
binaries: eclipsing
Abstract:
We present a new automated method to identify instrumental features
masquerading as small, long-period planets in the Kepler planet
candidate catalog. These systematics, mistakenly identified as planet
transits, can have a strong impact on occurrence rate calculations
because they cluster in a region of parameter space where Kepler's
sensitivity to planets is poor. We compare individual transit-like
events to a variety of models of real transits and systematic events
and use a Bayesian information criterion to evaluate the likelihood
that each event is real. We describe our technique and test its
performance on simulated data. Results from this technique are
incorporated in the Kepler Q1-Q17 DR24 planet candidate catalog of
Coughlin et al. (2016, Cat. J/ApJS/224/12)
Description:
We report on a new method for identifying and rejecting false-alarm
candidates at long periods. This method, which we dub Marshall fits
the individual transit events for candidates with models of transits
and commonly found artifacts and evaluates which one is more probable,
based on a Bayesian information criterion (BIC).
We apply this test to KOIs in the Q1-Q17 DR24 catalog (Coughlin et
al. 2016, Cat. J/ApJS/224/12) with orbital periods >150 days.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 72 314 Summary of planet candidate KOIs from Q1-Q17 DR24
with periods greater than 150 days examined
by Marshall
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/217/18 : Potential transit signals in Kepler Q1-Q17 (Seader+, 2015)
J/ApJS/224/12 : Kepler planetary candidates. VII. 48-month (Coughlin+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- KOI KOI name (KNNNNN.NN)
11- 18 I8 --- KIC Kepler identification number
20 I1 --- TCE Threshold crossing event. Order in which this
KOI was found around the target star by the
Kepler pipeline in Q1-Q17
22- 23 I2 --- NTrans Number of observed transits as measured by
the pipeline
25- 34 F10.6 d Per Period (1)
36- 43 F8.6 d e_Per ?=0 rms uncertainty on Per
45- 53 F9.5 Rgeo Rad Radius in R⊕ (1)
56- 64 F9.5 Rgeo e_Rad ?=0 rms uncertainty on Rad
66- 72 E7.2 --- Score Confidence Marshall assigns to a KOI (2)
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Note (1): Period and radius values are taken from Seader et al.
(2015, Cat. J/ApJS/217/18) and may differ slightly from the final values in
Coughlin et al. (2016, Cat. J/ApJS/224/12).
Note (2): Negative scores indicate high confidence that a KOI is due to a
transit while positive scores indicate lower confidence. KOIs with scores >10
are deemed to be false positives. The score given in the table is equal to the
score of the third strongest individual event for the KOI, which indicates
how close the KOI is to being marked as a false positive.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 25-Jul-2017