J/ApJS/246/8 RR Lyrae star candidates from SDSS-DR15 (Zhang+, 2020)
RR Lyrae star candidates from SDSS databases by cost-sensitive Random Forests.
Zhang J., Zhang Y., Zhao Y.
<Astrophys. J. Suppl. Ser., 246, 8 (2020)>
=2020ApJS..246....8Z 2020ApJS..246....8Z
ADC_Keywords: Stars, variable; Abundances, [Fe/H]; Photometry, SDSS
Keywords: RR Lyrae variable stars; Stellar types; Astronomy databases;
Metallicity; Random Forests; Astrostatistics; Astronomy data analysis
Abstract:
With the increase of known RR Lyrae stars, it is reliable to create
classifiers of RR Lyrae stars based on their photometric data or
combined photometric and spectroscopic data. Nevertheless the total
number of known RR Lyrae stars is still too small compared with the
large survey databases. So classification of RR Lyrae stars and other
sources belongs to imbalanced learning. Based on Sloan Digital Sky
Survey (SDSS) photometric and spectroscopic data, we apply
cost-sensitive Random Forests fit for imbalanced learning to preselect
RR Lyrae star candidates. Only with photometric data, u-g,g-r,r-i,i-z
is the best input pattern. While also considering physical parameters
(Teff, [Fe/H], log(g)), the optimal input pattern is Teff, [Fe/H],
log(g), u-g,g-r,r-i,i-z, at this moment for cost-sensitive Random
Forests, the performance metrics of completeness, contamination, and
Matthews correlation coefficient are 0.975, 0.019, and 0.975,
respectively. It indicates that adding stellar physical parameters is
helpful for identifying RR Lyrae stars from other stars. We apply the
best classifiers on the SDSS photometric data and combined photometric
data with physical parameters to select RR Lyrae star candidates.
Finally 11,041 photometric candidates with spectral type A and F are
obtained, and then 304 candidates with physical parameters are
selected out. Among the 304 candidates, a small part are HB stars, BS
stars, RGB stars, and peculiar stars, and the rest are unknown in the
Simbad database. These candidates may be used as the input catalog for
time-series follow-up observations.
Description:
SDSS is a major multifilter imaging and spectroscopic survey supported
by a 2.5m optical telescope, which provides a wide field of view, and
has five filters located in the u, g, r, i, and z bands, which range
from 0.36 to 0.90um. The processed data include all photometric and
spectroscopic observations. Compared to the prior SDSS Data Release,
SDSS Data Release 15 (DR15) provides more robust and precise
photometric and spectroscopic data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 128 304 The catalog of RR Lyrae star candidates
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam, 2015)
J/AJ/132/1202 : RR Lyrae in Northern Sky Variability Survey (Kinemuchi+, 2006)
J/A+A/548/A79 : INTEGRAL-OMC optically variable sources (Alfonso-Garzon+, 2012)
J/ApJS/203/32 : Machine-learned ASAS Classif. Cat. (MACC) (Richards+, 2012)
J/ApJ/763/32 : Galactic halo RRab stars from CSS (Drake+, 2013)
J/ApJ/765/154 : RR Lyrae stars in the Catalina Sky Survey (Drake+, 2013)
J/AJ/146/101 : LINEAR. III. Catalog of periodic variables (Palaversa+, 2013)
J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)
J/MNRAS/446/2251 : Southern Catalina Survey type-ab RR Lyrae (Torrealba+, 2015)
J/AcA/66/131 : VI light curves of SMC and LMC RR Lyrae (Soszynski+, 2016)
J/MNRAS/469/3688 : CSS Periodic Variable Star Catalogue (Drake+, 2017)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- OT Object type for the 14 known sources in SIMBAD;
column added by CDS from Table 3
5- 8 A4 --- --- [SDSS]
10- 28 A19 --- SDSS SDSS identifier (JHHMMSS.ss+DDMMSS.s)
30- 40 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000)
42- 53 F12.8 deg DEdeg [-17/83.2] Declination in decimal degrees (J2000)
55- 62 F8.3 K Teff [4716/8902] Effective temperature
64- 74 F11.8 [Sun] [Fe/H] [-3.1/0.3] Metallicity
76- 83 F8.6 [cm/s2] log(g) [1.3/4.7] log surface gravity
85- 92 F8.5 mag umag [14.7/21.9] Apparent SDSS u band (AB) magnitude
94-101 F8.5 mag gmag [13.5/25.2] Apparent SDSS g band (AB) magnitude
103-110 F8.5 mag rmag [13.2/24.9] Apparent SDSS r band (AB) magnitude
112-119 F8.5 mag imag [13.5/20.1] Apparent SDSS i band (AB) magnitude
121-128 F8.5 mag zmag [13/19.5] Apparent SDSS z band (AB) magnitude
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Apr-2020