J/MNRAS/502/5147 Anomaly detection in the ZTF DR3 (Malanchev+, 2021)
Anomaly detection in the Zwicky Transient Facility DR3.
Malanchev K.L., Pruzhinskaya M.V., Korolev V.S., Aleo P.D., Kornilov M.V.,
Ishida E.E.O., Krushinsky V.V., Mondon F., Sreejith S., Volnova A.A.,
Belinski A.A., Dodin A.V., Tatarnikov A.M., Zheltoukhov S.G.,
(The SNAD Team)
<Mon. Not. R. Astron. Soc., 502, 5147-5175 (2021)>
=2021MNRAS.502.5147M 2021MNRAS.502.5147M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Stars, distances ; Optical
Keywords: methods: data analysis - astronomical data bases: miscellaneous -
stars: variables: general
Abstract:
We present results from applying the SNAD anomaly detection pipeline
to the third public data release of the Zwicky Transient Facility (ZTF
DR3). The pipeline is composed of three stages: feature extraction,
search of outliers with machine learning algorithms, and anomaly
identification with followup by human experts. Our analysis
concentrates in three ZTF fields, comprising more than 2.25 million
objects. A set of four automatic learning algorithms was used to
identify 277 outliers, which were subsequently scrutinized by an
expert. From these, 188 (68 per cent) were found to be bogus light
curves - including effects from the image subtraction pipeline as well
as overlapping between a star and a known asteroid, 66 (24 per cent)
were previously reported sources whereas 23 (8 per cent) correspond to
non-catalogued objects, with the two latter cases of potential
scientific interest (e.g. one spectroscopically confirmed RS Canum
Venaticorum star, four supernovae candidates, one red dwarf flare).
Moreover, using results from the expert analysis, we were able to
identify a simple bi-dimensional relation that can be used to aid
filtering potentially bogus light curves in future studies. We provide
a complete list of objects with potential scientific application so
they can be further scrutinised by the community. These results
confirm the importance of combining automatic machine learning
algorithms with domain knowledge in the construction of recommendation
systems for astronomy. Our code is publicly available.
Description:
The ZTF is a 48-inch Schmidt telescope on Mount Palomar, equipped with
a 47deg2 camera, which allows rapid scanning of the entire north
sky. The ZTF survey started on 2018 March and during its initial phase
has observed around a billion objects (Bellm et al.
2019PASP..131a8002B 2019PASP..131a8002B).
In this work, we analysed data from the first 9.4 months of the ZTF
survey, between 2018 March 17 and December 31 (58194=<MJD=<58483).
This period includes data from ZTF private survey, thus having a
better cadence than the rest of DR3.
Light curves from ZTF DR3 are spread over 1020 fields, with objects
within the same field being sampled with a similar cadence - on
average ∼1d for the Galactic plane and ∼3d for the Northern-equatorial
sky. In order to minimize effects due to different cadences, we
performed our analysis in three separate fields: 'M 31' (a part of ZTF
field 695), which includes the Andromeda galaxy (Messier 1781), 'deep'
(ZTF field 795), located far from the Galactic plane, and 'disk' (ZTF
field 805), located in the Galaxy plane.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled1.dat 158 89 A complete list of anomaly candidates in the
M 31, deep, and disk fields
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Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Field Field name (M 31, Deep or Disk)
6- 20 I15 --- ID ZTF DR3 object identifier
22- 69 A48 --- OName Alternative name
71- 79 F9.5 deg RAdeg Right ascension (J2000)
81- 88 F8.5 deg DEdeg Declination (J2000)
90- 94 F5.2 mag rmagmin Minimum value of the r-band magnitude
96- 99 F4.2 mag e_rmagmin Error on rmagmin
101-105 F5.2 mag rmagmax Maximum value of the r-band magnitude
107-110 F4.2 mag e_rmagmax Error on rmagmax
112-117 F6.3 mag E(B-V) Reddening E (B-V)
119-122 A4 pc Dist Distance
124-129 F6.2 mag rMAGmax ? Maximum value of the r-band absolute
magnitude
131 A1 --- l_P0 Limit flag on P0
133-139 F7.3 d P0 ? Period (1)
141-152 A12 --- Type Object type (2)
154-158 A5 --- Ref References (3)
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Note (1): The best period extracted from either the Lomb-Scargle periodogram or
one of the catalogues listed in the ZTF-viewer or determined by us
Note (2): Type as follows:
AM = AM Herculis-type variable
AGB = Asymptotic Giant Branch Star
C = Carbon star
DBF = Distant binary, full period
Delta Cep = Classical Cepheid
EA = β Persei-type (Algol) eclipsing system
INS = Orion variable with rapid light variations
L = Slow irregular variable, stars are often attributed to this type
because of being insufficiently studied
LPV = Long Period Variable
Mira = o (omicron) Ceti-type variable
MSINE = Star showing modulated sinusoids
PNV = Possible nova
RRAB = RR Lyrae variable with asymmetric light curves
RSCVN = RS Canum Venaticorum-type binary system
RSG = Red supergiant
SN = Supernova
SR = Semiregular variable
UG = U Geminorum-type variable, quite often called dwarf nova
UGSS = SS Cygni-type variable
UGZ = Z Camelopardalis-type star
VAR = Variable of unspecified type
YSO = Young stellar Object of unspecified variable type
Note (3): References as follows:
1 = Watson et al. (2006SASS...25...47W 2006SASS...25...47W)
2 = Heinze et al. (2018AJ....156..241H 2018AJ....156..241H, Cat. J/AJ/156/241)
3 = Chen et al. (2020ApJS..249...18C 2020ApJS..249...18C)
4 = Marton et al. (2016MNRAS.458.3479M 2016MNRAS.458.3479M, Cat. J/MNRAS/458/3479)
5 = Vioque et al. (2020A&A...638A..21V 2020A&A...638A..21V, Cat. J/A+A/638/A21)
6 = Usatov & Nosulchik (2008OEJV...87....1U 2008OEJV...87....1U, Cat. J/other/OEJV/87)
7 = Wozniak et al. (2004AJ....128.2965W 2004AJ....128.2965W, Cat. J/AJ/128/2965)
8 = Edelson & Malkan (2012ApJ...751...52E 2012ApJ...751...52E, Cat. J/ApJ/751/52)
9 = Nesci et al. (2018RMxAA..54..341N 2018RMxAA..54..341N)
10 = Wright et al. (2009MNRAS.400.1413W 2009MNRAS.400.1413W, Cat. J/MNRAS/400/1413)
11 = Drake et al. (2009ApJ...696..870D 2009ApJ...696..870D, Cat. J/ApJ/696/870)
12 = Graham et al. (2018ATel11745....1G 2018ATel11745....1G)
13 = Delgado et al. (2018TNSTR.345....1D 2018TNSTR.345....1D)
14 = Massey et al. (2009ApJ...703..420M 2009ApJ...703..420M, Cat. J/ApJ/703/420)
15 = Carey (2017TNSTR1418....1C 2017TNSTR1418....1C)
16 = Lee et al. (2014ApJ...785...11L 2014ApJ...785...11L)
17 = Humphreys et al. (2017ApJ...836...64H 2017ApJ...836...64H, Cat. J/ApJ/836/64)
18 = Kodric et al. (2018AJ....156..130K 2018AJ....156..130K, Cat. J/AJ/156/130)
19 = Magnier et al. (1997A&AS..126..401M 1997A&AS..126..401M, Cat. J/A+AS/126/401)
20 = Ovcharov et al. (2013ATel.5569....1O 2013ATel.5569....1O)
21 = Shumkov et al. (2016ATel.9470....1S 2016ATel.9470....1S)
22 = Hornoch & Kucakova (2015ATel.7462....1H 2015ATel.7462....1H)
23 = Kodric et al. (2013AJ....145..106K 2013AJ....145..106K, Cat. J/AJ/145/106)
24 = Joshi et al. (2003A&A...402..113J 2003A&A...402..113J, Cat. J/A+A/402/113)
25 = Kaluzny et al. (1999AJ....118..346K 1999AJ....118..346K, Cat. J/AJ/118/346)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 31-Oct-2023