J/ApJ/828/99 Kepler pipeline transit signal recovery. III. (Christiansen+, 2016)
Measuring transit signal recovery in the Kepler pipeline.
III. Completeness of the Q1-Q17 DR24 planet candidate catalogue with important
caveats for occurrence rate calculations.
Christiansen J.L., Clarke B.D., Burke C.J., Jenkins J.M., Bryson S.T.,
Coughlin J.L., Mullally F., Thompson S.E., Twicken J.D., Batalha N.M.,
Haas M.R., Catanzarite J., Campbell J.R., Uddin A.K., Zamudio K.,
Smith J.C., Henze C.E.
<Astrophys. J., 828, 99-99 (2016)>
=2016ApJ...828...99C 2016ApJ...828...99C (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Models
Keywords: methods: data analysis - techniques: photometric
Abstract:
With each new version of the Kepler pipeline and resulting planet
candidate catalog, an updated measurement of the underlying planet
population can only be recovered with a corresponding measurement of
the Kepler pipeline detection efficiency. Here we present measurements
of the sensitivity of the pipeline (version 9.2) used to generate the
Q1-Q17 DR24 planet candidate catalog. We measure this by injecting
simulated transiting planets into the pixel-level data of 159013 targets
across the entire Kepler focal plane, and examining the recovery rate.
Unlike previous versions of the Kepler pipeline, we find a strong
period dependence in the measured detection efficiency, with longer
(>40 day) periods having a significantly lower detectability than
shorter periods, introduced in part by an incorrectly implemented veto.
Consequently, the sensitivity of the 9.2 pipeline cannot be cast as a
simple one-dimensional function of the signal strength of the candidate
planet signal, as was possible for previous versions of the pipeline.
We report on the implications for occurrence rate calculations based
on the Q1-Q17 DR24 planet candidate catalog, and offer important
caveats and recommendations for performing such calculations. As
before, we make available the entire table of injected planet
parameters and whether they were recovered by the pipeline, enabling
readers to derive the pipeline detection sensitivity in the planet
and/or stellar parameter space of their choice.
Description:
Here we describe the third transit injection experiment, which tests
the entire Kepler observing baseline (Q1-Q17) for the first time across
all 84 CCD channels. It was performed to measure the sensitivity of
the Kepler pipeline used to generate the Q1-Q17 Data Release 24 (DR24)
catalog of Kepler Objects of Interest (Coughlin et al. 2016, J/ApJS/224/12)
available at the NASA Exoplanet Archive (Akeson et al. 2013PASP..125..989A 2013PASP..125..989A).
The average detection efficiency describes the likelihood that the Kepler
pipeline would successfully recover a given transit signal. To measure
this property we perform a Monte Carlo experiment where we inject the
signatures of simulated transiting planets around 198154 target stars,
one per star, across the focal plane starting with the Q1-Q17 DR24
calibrated pixels. The simulated transits are generated using the
Mandel & Agol (2002ApJ...580L.171M 2002ApJ...580L.171M) model.
Of the injections, 159013 resulted in three or more injected transits
(the minimum required for detection by the pipeline) and were used for
the subsequent analysis.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 153 159013 Injected and Recovered Parameters of
the Injected Transiting Planets
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/207/35 : Kepler pipeline signal-to-noise studies (Christiansen+, 2013)
J/ApJ/810/95 : Kepler pipeline S/N studies. II. 2011 data
(Christiansen+, 2015)
J/ApJ/812/46 : Transit metric for Q1-Q17 Kepler candidates (Thompson+, 2015)
J/ApJS/217/18 : Potential transit signals in Kepler Q1-Q17 (Seader+, 2015)
J/ApJ/822/86 : False positive probabilities for Q1-Q17 DR24 KOIs
(Morton+, 2016)
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
--------------------------------------------------------------------------------
1- 8 I8 --- KIC [757076/12984422] Kepler identifier of the target
10- 11 I2 --- Sky [1/84] Sky group in which the target is located
13- 20 F8.4 d Per Orbital period of the injected transit signal
22- 31 F10.4 d T0 Epoch of the injected transit signal; in BMJD
33- 37 I5 ppm Td Depth of the injected transit signal
39- 45 F7.2 h Tdur Duration of the injected transit
47- 52 F6.4 --- b Impact parameter of the injected transit signal
54- 59 F6.4 --- Rp/R* Ratio of the planet radius to the stellar radius
for the injected signal
61- 69 F9.3 --- a/R* Ratio of the semimajor axis of the planetary
orbit to the stellar radius for the injected
signal
71 I1 --- Signal [0/1] Whether the transit signal was injected on
the target star (0) or offset from the target
star (1) to mimic a false positive
73- 79 F7.4 arcsec Offset Distance from the target source location to
the location of the injected signal, for targets
injected off the target source
81- 88 F8.4 --- E-MES Expected multiple event statistic (MES) of
the injected transit signal
90 I1 --- Recov [0/2]? Recovery of the injected signal by
the pipeline (1)
92- 99 F8.4 --- R-MES ? Maximum MES measured by the pipeline on
the recovered signal
101-108 F8.4 d R-Per ? Orbital period of the recovered signal
110-119 F10.4 d R-T0 ? Epoch of the recovered signal; in BJMD
121-125 I5 ppm R-Td ? Central transit depth of the recovered signal
127-131 F5.2 h R-Tdur ? Transit duration of the recovered signal
133-137 F5.3 --- R-b ? Impact parameter of the recovered signal
139-144 F6.4 --- R-Rp/R* ? Ratio of the planet radius to the stellar
radius for the recovered signal
146-153 F8.3 --- R-a/R* ? Ratio of the semimajor axis of the planetary
orbit to the stellar radius for the recovered
signal
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Note (1): Recovery as follows:
0 = Successful recovery;
1 = Unsuccessful recovery;
2 = The signal was recovered by the pipeline at an integer alias of the
injected period.
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History:
From electronic version of the journal
References:
Christiansen et al. Paper I. 2013ApJS..207...35C 2013ApJS..207...35C, Cat. J/ApJS/207/35
Christiansen et al. Paper II. 2015ApJ...810...95C 2015ApJ...810...95C, Cat. J/ApJ/810/95
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 05-Mar-2018