J/ApJ/932/118 Anomalies in the ZTF cat. of periodic var. stars (Chan+, 2022)
Searching for anomalies in the ZTF Catalog of Periodic Variable Stars.
Chan H.-S., Villar V.A., Cheung S.-H., Ho S., O'Grady A.J.G., Drout M.R.,
Renzo M.
<Astrophys. J., 932, 118 (2022)>
=2022ApJ...932..118C 2022ApJ...932..118C
ADC_Keywords: Stars, variable; Optical
Keywords: Mira variable stars ; Semi-regular variable stars ;
Periodic variable stars ; Convolutional neural networks ;
Red giant stars ; Astrophysical dust processes ;
Asymptotic giant branch stars ; Peculiar variable stars ;
Young stellar objects ; Late stellar evolution ; Late-type giant stars
Abstract:
Periodic variables illuminate the physical processes of stars
throughout their lifetime. Wide-field surveys continue to increase our
discovery rates of periodic variable stars. Automated approaches are
essential to identify interesting periodic variable stars for
multiwavelength and spectroscopic follow-up. Here we present a novel
unsupervised machine-learning approach to hunt for anomalous periodic
variables using phase-folded light curves presented in the Zwicky
Transient Facility Catalogue of Periodic Variable Stars by Chen et al.
We use a convolutional variational autoencoder to learn a
low-dimensional latent representation, and we search for anomalies
within this latent dimension via an isolation forest. We identify
anomalies with irregular variability. Most of the top anomalies are
likely highly variable red giants or asymptotic giant branch stars
concentrated in the Milky Way galactic disk; a fraction of the
identified anomalies are more consistent with young stellar objects.
Detailed spectroscopic follow-up observations are encouraged to reveal
the nature of these anomalies.
Description:
We extract 730184 out of 781602 available periodic variable star light
curves in the ZTF Catalog of Periodic Variable Stars (ZTF CPVS;
Chen+ 2020, J/ApJS/249/18) that contain at least one 2.5σ and
3σ detection in g and r band, respectively.
See Section 2 for details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 63 730184 All periodic variables space ranked by their
anomaly scores computed in the Cartesian latent
space
table5.dat 63 730184 All periodic variables space ranked by their
anomaly scores computed in the Spherical latent
space
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
II/328 : AllWISE Data Release (Cutri+ 2013)
I/329 : URAT1 Catalog (Zacharias+ 2015)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
II/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
VII/233 : 2MASS All-Sky Extended Source Catalog (XSC) (IPAC/UMass, 2003-2006)
J/A+A/417/263 : Catalogue of Algol type binary stars (Budding+, 2004)
J/AJ/130/776 : Secular evolution in Mira var. pulsations (Templeton+, 2005)
J/A+A/463/275 : Chandra obs. of Serpens SFR (Giardino+, 2007)
J/A+A/506/1277 : Modelling of Magellanic Cloud C/O stars (Groenewegen+, 2009)
J/MNRAS/399/2063 : LMC red giants in D sequence (Nicholls+, 2009)
J/A+A/532/A54 : GRAMS carbon-star model grid (Srinivasan+, 2011)
J/A+A/548/A92 : VrI light curves of NGC1904 variables (Kains+, 2012)
J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/MNRAS/465/4530 : outlier detection algorithm for SDSS galaxies (Baron+, 2017)
J/MNRAS/469/3688 : CSS Periodic Variable Star Catalogue (Drake+, 2017)
J/A+A/604/A29 : MC Type II & anomalous Cepheids PL & PR (Groenewegen+, 2017)
J/ApJS/232/16 : Mira stars discovered in LAMOST DR4 (Yao+, 2017)
J/A+A/619/A51 : Type II Cepheids in the Galactic bulge (Braga+, 2018)
J/ApJS/237/28 : WISE catalog of periodic variable stars (Chen+, 2018)
J/AJ/156/241 : Variable stars measured by ATLAS (Heinze+, 2018)
J/MNRAS/477/2276 : Type II Cepheids abundances (Kovtyukh+, 2018)
J/A+A/627/A135 : VRI photometry of IC5070 variable stars (Bhardwaj+, 2019)
J/A+A/625/A1 : RR Lyrae variables NIR light-curve templates (Braga+, 2019)
J/ApJ/883/58 : Cepheids from VVV in the South Gal. midplane (Dekany+, 2019)
J/A+A/623/A110 : Gaia DR2. Variable stars in CMD (Gaia Collaboration+, 2019)
J/MNRAS/489/3591 : Open Supernova Cat. anomaly detection (Pruzhinskaya+, 2019)
J/other/Sci/365.478 : Milky Way classical Cepheids sample (Skowron+, 2019)
J/A+A/644/A95 : omega Cen RR Lyrae and Type II Cepheids (Braga+, 2020)
J/ApJS/249/18 : The ZTF catalog of periodic variable stars (Chen+, 2020)
J/ApJ/905/94 : Classif. for PS1-MDS SNe with SuperRAENN (Villar+, 2020)
J/MNRAS/502/5147 : Anomaly detection in the ZTF DR3 (Malanchev+, 2021)
J/AJ/162/101 : K2 ugri & Ha phot. in the Lagoon Nebula (Venuti+, 2021)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- ZTF ZTF identifier
24- 29 I6 --- ID [1/781604] Catalog internal identifier
31- 35 A5 --- Class Class label (G1)
37- 45 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
47- 55 F9.5 deg DEdeg [-21/81] Declination in decimal degrees (J2000)
57- 63 F7.5 --- Score [0/1] Anomaly score
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- ZTF ZTF identifier
24- 29 I6 --- ID [1/781604] Catalog internal identifier
31- 35 A5 --- Class Class label (G1)
37- 45 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
47- 55 F9.5 deg DEdeg [-21/81] Declination in decimal degrees (J2000)
57- 63 F7.5 --- Score [0/1] Anomaly score
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Global notes:
Note (G1): Class (from Chen+ 2020, J/ApJS/249/18) as follows:
BYDra = BY Draconis rotational variable (84488 occurrences)
CEP = Classical Cepheid (959 occurrences)
CEPII = Type II Cepheid (323 occurrences)
DSCT = Low-amplitude δ Scuti star (16381 occurrences)
EA = EA-type eclipsing binary (48703 occurrences)
EW = EW-type eclipsing binary (352395 occurrences)
Mira = Mira variable (7354 occurrences)
RR = RRab Lyrae (28844 occurrences)
RRc = RRc Lyrae (12461 occurrences)
RSCVN = RS CVn (Canum Venaticorum) rotational variable (81139 occurrences)
SR = Semiregular variable (97137 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Mar-2025