J/AJ/151/101 Kepler Mission. VIII. 285 false positives (Abdul-Masih+, 2016)
Kepler eclipsing binary stars. VIII. Identification of false positive eclipsing
binaries and re-extraction of new light curves.
Abdul-masih M., Prsa A., Conroy K., Bloemen S., Boyajian T., Doyle L.R.,
Johnston C., Kostov V., Latham D.W., Matijevic G., Shporer A.,
Southworth J.
<Astron. J., 151, 101 (2016)>
=2016AJ....151..101A 2016AJ....151..101A (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing
Keywords: binaries: eclipsing - catalogs - methods: analytical -
methods: data analysis - methods: statistical -
techniques: photometric
Abstract:
The Kepler mission has provided unprecedented, nearly continuous
photometric data of ∼200000 objects in the ∼105deg2 field of view
(FOV) from the beginning of science operations in May of 2009 until
the loss of the second reaction wheel in May of 2013. The Kepler
Eclipsing Binary Catalog contains information including but not
limited to ephemerides, stellar parameters, and analytical
approximation fits for every known eclipsing binary system in the
Kepler FOV. Using target pixel level data collected from Kepler in
conjunction with the Kepler Eclipsing Binary Catalog, we identify
false positives among eclipsing binaries, i.e., targets that are not
eclipsing binaries themselves, but are instead contaminated by
eclipsing binary sources nearby on the sky and show eclipsing binary
signatures in their light curves. We present methods for identifying
these false positives and for extracting new light curves for the true
source of the observed binary signal. For each source, we extract
three separate light curves for each quarter of available data by
optimizing the signal-to-noise ratio, the relative percent eclipse
depth, and the flux eclipse depth. We present 289 new eclipsing
binaries in the Kepler FOV that were not targets for observation, and
these have been added to the catalog. An online version of this
catalog with downloadable content and visualization tools is
maintained at http://keplerEBs.villanova.edu/.
Description:
The Kepler mission was launched in 2009 and provided photometric data
for ∼200000 objects in the 105deg2 contained in the Kepler field of
view (FOV; Batalha et al. 2013, Cat. J/ApJS/204/24). Each of the 95
million Kepler pixels cover 3.98*3.98'' and are designed to maximize
the number of resolvable stars with magnitudes brighter than 15. There
are approximately 500000 objects in the Kepler FOV that are brighter
than V=16; however, only ∼200000 were assigned as targets for
observation, leaving many bright objects in the field unobserved.
Since the main goal of Kepler is to find Earth-sized planets in the
habitable zone of Sun-like stars, the targets that were chosen for
observation were those with the highest potential for terrestrial
planet detection. Thus, many objects in the Kepler FOV have not been
observed. Due to the proximity of some of these unobserved objects to
the identified targets, the possibility of contaminated signals
arises. Of the observed targets, 2772 eclipsing binaries have been
found and cataloged in the Kepler Eclipsing Binary Catalog
(http://keplerebs.villanova.edu/; see also Kirk et al. 2016, Cat.
J/AJ/151/68).
A false positive is a case where the signal from a binary object in
close proximity to a target contaminates the aperture pixels, causing
the target light curve to show a binary signal. This means that the
incorrect object is being identified as the source of the binary
signal.
Once the source of the binary signal is identified, a new light curve
can be extracted. The re-extraction process is comprised of several
automated steps and results in three new light curves generated for
the true source of the binary signal for each quarter of available
data. These light curves are generated by optimizing the
signal-to-noise ratio (S/N light curve), percent eclipse depth (PED
light curve), and flux eclipse depth (FED light curve). Before
re-extracting the new light curves, we obtain the S/N, the PED, and
the FED for the original false positive integrated aperture light
curve.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 135 285 *Table comparing the parameters from the original
integrated aperture light curve to the new
re-extracted parameters
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Note on table1.dat: Downloaded on http://keplerebs.villanova.edu/indirect -
2016-09-28.
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See also:
J/AJ/151/68 : Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)
J/AJ/147/45 : Kepler mission. IV. (Conroy+, 2014)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/AJ/142/160 : Kepler Mission. II. Eclipsing binaries in DR2 (Slawson+, 2011)
http://keplerebs.villanova.edu/indirect : Catalog V3 - indirect
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I09 --- FP [1725193/12736658] KIC number of the False
Positive (1)
11- 13 A3 --- f_KIC [N/A] Flag on KIC (N/A)
15- 23 I09 --- KIC [1725199/12691405]? Kepler Input Catalog number of
the true source
25- 31 F7.3 --- S/No [0.004/189.1] old Signal to Noise ratio (2)
33- 39 F7.3 --- S/Nn [0.34/430.84] new Signal to Noise ratio
41- 46 F6.3 % PEDo [-0.004/41.5] old relative Percent Eclipse Depth (2)
48- 53 F6.3 % PEDn [0.17/86.12] new relative Percent Eclipse Depth
55- 63 F9.3 --- FEDo [-5/17859] old Flux Eclipse Depth (2)
65- 73 F9.3 --- FEDn [1/48836] new Flux Eclipse Depth
75- 76 A2 --- LC0 [Q0] Indicates re-extracted Q0 quarter light curve
78- 79 A2 --- LC1 [Q1] Indicates re-extracted Q1 quarter light curve
81- 82 A2 --- LC2 [Q2] Indicates re-extracted Q2 quarter light curve
84- 85 A2 --- LC3 [Q3] Indicates re-extracted Q3 quarter light curve
87- 88 A2 --- LC4 [Q4] Indicates re-extracted Q4 quarter light curve
90- 91 A2 --- LC5 [Q5] Indicates re-extracted Q5 quarter light curve
93- 94 A2 --- LC6 [Q6] Indicates re-extracted Q6 quarter light curve
96- 97 A2 --- LC7 [Q7] Indicates re-extracted Q7 quarter light curve
99-100 A2 --- LC8 [Q8] Indicates re-extracted Q8 quarter light curve
102-103 A2 --- LC9 [Q9] Indicates re-extracted Q9 quarter light curve
105-107 A3 --- LC10 [Q10] Indicates re-extracted Q10 quarter light curve
109-111 A3 --- LC11 [Q11] Indicates re-extracted Q11 quarter light curve
113-115 A3 --- LC12 [Q12] Indicates re-extracted Q12 quarter light curve
117-119 A3 --- LC13 [Q13] Indicates re-extracted Q13 quarter light curve
121-123 A3 --- LC14 [Q14] Indicates re-extracted Q14 quarter light curve
125-127 A3 --- LC15 [Q15] Indicates re-extracted Q15 quarter light curve
129-131 A3 --- LC16 [Q16] Indicates re-extracted Q16 quarter light curve
133-135 A3 --- LC17 [Q17] Indicates re-extracted Q17 quarter light curve
--------------------------------------------------------------------------------
Note (1): A false positive is a case where the signal from a binary object in
close proximity to a target contaminates the aperture pixels, causing the
target light curve to show a binary signal. This means that the incorrect
object is being identified as the source of the binary signal.
Note (2): The Flux Eclipse Depth (FED) can be obtained by measuring the
difference between the out-of-eclipse flux and the in-eclipse flux. The PED
is then determined by dividing the FED by the out-of-eclipse flux. The S/N
is determined by first subtracting the polyfit solution from the
phase-folded light curve. The noise is determined by calculating the
standard deviation of the out-of-eclipse region and then the FED is divided
by the noise to obtain the S/N.
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History:
From electronic version of the journal
References:
Prsa et al., Paper I 2011AJ....141...83P 2011AJ....141...83P, Cat. J/AJ/141/83
Slawson et al., Paper II 2011AJ....142..160S 2011AJ....142..160S, Cat. J/AJ/142/160
Matijevic et al., Paper III 2012AJ....143..123M 2012AJ....143..123M
Conroy et al., Paper IV 2014AJ....147...45C 2014AJ....147...45C, Cat. J/AJ/147/45
Conroy et al., Paper V 2014PASP..126..914C 2014PASP..126..914C, Cat. J/PASP/126/914
LaCourse et al., Paper VI 2015MNRAS.452.3561L 2015MNRAS.452.3561L, Cat. J/MNRAS/452/3561
Kirk et al., Paper VII 2016AJ....151...68K 2016AJ....151...68K, Cat. J/AJ/151/68
(End) Sylvain Guehenneux [CDS] 19-Aug-2016