J/AJ/156/241 A first catalog of variable stars measured by ATLAS (Heinze+, 2018)
A first catalog of variable stars measured by the Asteroid Terrestrial-impact
Last Alert System (ATLAS).
Heinze A.N., Tonry J.L., Denneau L., Flewelling H., Stalder B., Rest A.,
Smith K.W., Smartt S.J., Weiland H.
<Astron. J., 156, 241-241 (2018)>
=2018AJ....156..241H (SIMBAD/NED BibCode)ADC_Keywords: Stars, variable ; Binaries, eclipsing ; Photometry ; Optical ;
Stars, distances ; Photometry, SDSS ; Surveys
Keywords: binaries: eclipsing - catalogs - stars: variables: delta Scuti -
stars: variables: general - stars: variables: RR Lyrae - surveys
Abstract:
The Asteroid Terrestrial-impact Last Alert System (ATLAS) carries out
its primary planetary defense mission by surveying about 13000 deg2
at least four times per night. The resulting data set is useful for
the discovery of variable stars to a magnitude limit fainter than r∼18,
with amplitudes down to 0.02 mag for bright objects. Here, we present
a Data Release One catalog of variable stars based on analyzing the light
curves of 142 million stars that were measured at least 100 times in
the first two years of ATLAS operations. Using a Lomb-Scargle periodogram
and other variability metrics, we identify 4.7 million candidate variables.
Through the Space Telescope Science Institute, we publicly release light
curves for all of them, together with a vector of 169 classification
features for each star. We do this at the level of unconfirmed candidate
variables in order to provide the community with a large set of
homogeneously analyzed photometry and to avoid pre-judging which types
of objects others may find most interesting. We use machine learning
to classify the candidates into 15 different broad categories based on
light-curve morphology. About 10% (427000 stars) pass extensive tests
designed to screen out spurious variability detections: we label these
as "probable" variables. Of these, 214000 receive specific classifications
as eclipsing binaries, pulsating, Mira-type, or sinusoidal variables:
these are the "classified" variables. New discoveries among the probable
variables number 315000, while 141000 of the classified variables are new,
including about 10400 pulsating variables, 2060 Mira stars, and
74700 eclipsing binaries.
Description:
ATLAS (Tonry et al. 2018PASP..130f4505T) is designed to detect small
(10-140 m) asteroids on their "final plunge" toward impact with Earth.
Because such asteroids can come from any direction and go from undetectable
to impact in less than a week, ATLAS scans the whole accessible sky every
few days. To achieve this, we use fully robotic 0.5 m f/2 Wright Schmidt
telescopes with 10560x10560 pixel STA1600 CCDs yielding a 5.4x5.4 degree
field of view with 1.86 arcsec pixels. The first ATLAS telescope commenced
operations in mid-2015 on the summit of Haleakala on the Hawaiian island
of Maui, and the second was installed in 2017 January/February at Maunaloa
Observatory on the big island of Hawaii. On a typical night, each ATLAS
telescope takes four 30 s exposures of 200-250 target fields covering
approximately one-fourth of the accessible sky. Together, the two telescopes
cover half of the accessible sky each night.
The ATLAS DR1 catalog we present herein makes a major contribution even
in the context of the great expansion of known variable stars described
in Section 1.1. It is based on analyzing the photometric time series
(light curves) of 142 million stars, which we refer to herein as the
"ATLAS light-curve set", and from which we identify 4.7 million as
candidate variables.
The ATLAS telescope on Haleakala observes with two customized, wide
filters designed to optimize detection of faint objects while still
providing some color information. The "cyan" filter (c; covering 420-650 nm)
is used during the two weeks surrounding the new Moon; the "orange" filter
(o; 560-820 nm) is used in lunar bright time. As described in Tonry et al.
(2018PASP..130f4505T), the o and c filters are well-defined photometric
bands with known color transformations linking them to the Pan-STARRS g, r,
and i bands (Magnier et al. 2016arXiv161205242M). This initial data release
is based on the first two years of operation of the Haleakala telescope
only and covers observations taken up through the end of 2017 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 1911 4817370 *ATLAS catalog of candidate variable stars
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Note on table4.dat: In Table 4, two-character prefixes encode which stage of the
ATLAS analysis produced the feature: "fp" means fourierperiod, "vf" means
varfeat, "df" means the feature came from our statistical analysis of
detections in the difference images, "ps" means from the proximity statistics
(i.e., the angular distance to nearest neighboring star), and "ls" means
lombscar.
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See also:
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
II/250 : Combined General Catalogue of Variable Stars (Samus+ 2004)
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
II/337 : VISTA Variables in the Via Lactea Survey DR1 (Saito+, 2012)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
J/AcA/48/35 : All Sky Automated Survey variable stars (Pojmamski 1998)
J/AJ/119/1901 : ROTSE all-sky surveys for variable stars (Akerlof+, 2000)
J/AcA/52/129 : DIA OGLE2 candidate variable stars catalog (Wozniak+, 2002)
J/AcA/59/33 : ASAS. Variable stars catalog in Kepler field.
(Pigulski+, 2009)
J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)
J/AJ/150/107 : Variable stars from TNTS. I. 2012-2014 (Yao+, 2015)
J/AJ/151/110 : BEST-II catalog of variables: CoRoT SRc02 field
(Klagyivik+, 2016)
J/MNRAS/469/3688 : CSS Periodic Variable Star Catalogue (Drake+, 2017)
J/AJ/156/204 : BEST-II catalog of variables. III. Puppis field
(Dreyer+, 2018)
J/ApJS/237/28 : WISE catalog of periodic variable stars (Chen+, 2018)
http://mastweb.stsci.edu/ps1casjobs : Pan-STARRS1 DR1 database, allowing to
query the ATLAS variable star database
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- ATOID Official ATLAS name
(ATO JDDD.dddd+DD.dddd)
19- 27 F9.5 deg RAdeg Right Ascension in decimal degrees
(J2000)
29- 37 F9.5 deg DEdeg Declination in decimal degrees
(J2000)
39- 41 I3 --- fp-c-pts [0/366] Number of c-band points
fourierperiod identified as good
43- 45 I3 --- fp-o-pts [0/417] Number of o-band points
fourierperiod identified as good
47- 58 F12.6 d fp-LSper [0.021735/14505.8] Original period
from fourierperiod's Lomb-Scargle
periodogram
60- 68 E9.6 --- fp-origLogFAP [0/41] PPFAP for fourierperiod's
Lomb-Scargle periodogram (1) (2)
70- 77 F8.6 mag fp-origRMS [0.00608/2.2687] rms scatter of
median-subtracted input magnitudes
that fourierperiod identified as
good
79- 86 F8.6 mag fp-magrms-c [0/4.76449] rms scatter of
median-subtracted c-band magnitudes
that fourierperiod identified as
good (1)
88- 95 F8.6 mag fp-magrms-o [0/2.20223] rms scatter of
median-subtracted o-band magnitudes
that fourierperiod identified as
good (1)
97- 107 F11.6 d fp-lngfitper [5/1500] Final master period from
the long-period Fourier fit (1)
109- 116 F8.6 mag fp-lngfitrms [0.005034/1.62378] rms scatter from
the final long-period fit
118- 128 F11.6 --- fp-lngfitchi [0.087306/4314.64] Χ2/N for
the long-period Fourier fit
130 I1 --- fp-Nfourl [1/4] Number of Fourier terms used
in the long-period fit
(fp-lngfournum) (1)
132- 141 F10.6 mag fp-lngmin-c [-30/29.4918] Minimum brightness
reached by the long-period fit to
the c-band photometry at any time
corresponding to an actual
measurement (1)
143- 151 F9.6 mag fp-lngmax-c [8.84805/50] Maximum brightness
reached by the long-period fit to
the c-band photometry at any time
corresponding to an actual
measurement (1)
153- 162 F10.6 mag fp-lngmin-o [-30/20.9016] Minimum brightness
reached by the long-period fit to
the o-band photometry at any time
corresponding to an actual
measurement (1)
164- 172 F9.6 mag fp-lngmax-o [8.18799/50] Maximum brightness
reached by the long-period fit to
the o-band photometry at any time
corresponding to an actual
measurement (1)
174- 181 E8.6 mag fp-lngfitrms-c [0/1.90675] rms scatter of residuals
from the long-period fit to the
c-band data (1)
183- 190 E8.6 mag fp-lngfitrms-o [0/1.58836] rms scatter of residuals
from the long-period fit to the
o-band data (1)
192- 202 E11.6 --- fp-lngfitchi-c [0/5217.93] Χ2/N for the
long-period Fourier fit to the
c-band data
204- 214 E11.6 --- fp-lngfitchi-o [0/3313.04] Χ2/N for the
long-period Fourier fit to the
o-band data
216- 228 F13.6 mag fp-lngconst-c [-13196.6/7064.02] Constant term in
the long-period fit to the c-band
data
230- 241 F12.6 mag fp-lngconst-o [-7516.3/9822.24] Constant term in
the long-period fit to the o-band
data
243- 254 E12.6 mag fp-sin1-c [-8545.78/9203.88] Sine coefficient
of the first Fourier term in the
long-period fit to the c-band data
(3)
256- 268 E13.6 mag fp-cos1-c [-16962/9486.04] Cosine coefficient
of the first Fourier term in the
long-period fit to the c-band data
(3)
270- 281 E12.6 mag fp-sin1-o [-7889.02/5158.65] Sine coefficient
of the first Fourier term in the
long-period fit to the o-band data
(3)
283- 294 E12.6 mag fp-cos1-o [-8299.74/5514.23] Cosine
coefficient of the first Fourier
term in the long-period fit to the
o-band data (3)
296- 304 E9.6 --- fp-PPFAPlong1 [0/41] PPFAP of residuals after
subtraction of the best long-period
Fourier fit with one term (2)
306- 317 E12.6 mag fp-sin2-c [-4987.1/3878.38]?=0 Sine
coefficient of the second Fourier
term in the long-period fit to the
c-band data (3)
319- 330 E12.6 mag fp-cos2-c [-7037.28/4419.9]?=0 Cosine
coefficient of the second Fourier
term in the long-period fit to the
c-band data (3)
332- 343 E12.6 mag fp-sin2-o [-2728/2875.01]?=0 Sine coefficient
of the second Fourier term in the
long-period fit to the o-band data
(3)
345- 356 E12.6 mag fp-cos2-o [-2322.39/2763.02]?=0 Cosine
coefficient of the second Fourier
term in the long-period fit to the
o-band data (3)
358- 366 E9.6 --- fp-PPFAPlong2 [0/41]?=0 PPFAP of residuals after
subtraction of the best long-period
Fourier fit with two terms (2)
368- 379 E12.6 mag fp-sin3-c [-6221.59/2566.56]?=0 Sine
coefficient of the third Fourier
term in the long-period fit to the
c-band data (3)
381- 392 E12.6 mag fp-cos3-c [-3703.32/3052.83]?=0 Cosine
coefficient of the third Fourier
term in the long-period fit to
the c-band data (3)
394- 405 E12.6 mag fp-sin3-o [-1031.2/1280.57]?=0 Sine
coefficient of the third Fourier
term in the long-period fit to the
o-band data (3)
407- 418 E12.6 mag fp-cos3-o [-3164.26/1140.22]?=0 Cosine
coefficient of the third Fourier
term in the long-period fit to
the o-band data (3)
420- 428 E9.6 --- fp-PPFAPlong3 [0/41]?=0 PPFAP of residuals after
subtraction of the best long-period
Fourier fit with three terms (2)
430- 441 E12.6 mag fp-sin4-c [-2971.96/2222.28]?=0 Sine
coefficient of the fourth Fourier
term in the long-period fit to the
c-band data (3)
443- 454 E12.6 mag fp-cos4-c [-2190.53/1883.03]?=0 Cosine
coefficient of the fourth Fourier
term in the long-period fit to
the c-band data (3)
456- 466 E11.6 mag fp-sin4-o [-948.079/1779.61]?=0 Sine
coefficient of the fourth Fourier
term in the long-period fit to the
o-band data (3)
468- 479 E12.6 mag fp-cos4-o [-1138.85/2195.2]?=0 Cosine
coefficient of the fourth Fourier
term in the long-period fit to
the o-band data (3)
481- 489 E9.6 --- fp-PPFAPlong4 [0/41]?=0 PPFAP of residuals after
subtraction of the best long-period
Fourier fit with four terms (2)
491- 501 F11.6 --- fp-hifreq-c [0/2961.99]?=0 A measure of the
relative power in the
high-frequency vs low-frequency
terms in the long-period Fourier
fit to the c-band
503- 513 F11.6 --- fp-hifreq-o [0/1623.17]?=0 A measure of the
relative power in the
high-frequency vs low-frequency
terms in the long-period Fourier
fit to the o-band
515- 527 F13.6 --- fp-timerev-c [0/128573]?=0 A measure of the
degree of invariance of the
long-period Fourier fit to the
c-band data with respect to the
reversal (i.e., mirroring) of the
time axis about the time of minimum
light (large value=invariant)
529- 540 F12.6 --- fp-timerev-o [0/30660]?=0 A measure of the
degree of invariance of the
long-period Fourier fit to the
o-band data with respect to the
reversal (i.e., mirroring) of the
time axis about the time of minimum
light (large value=invariant)
542- 552 F11.6 --- fp-phase180-c [0/1441.45]?=0 A measure of the
degree of invariance of the
long-period Fourier fit to the
c-band data with respect to a
180° phase shift
(large value=invariant)
554- 563 F10.6 --- fp-phase180-o [0/809.737]?=0 A measure of the
degree of invariance of the
long-period Fourier fit to the
o-band data with respect to a
180° phase shift
(large value=invariant)
565- 569 I5 --- fp-power-c [1/32766] Highest amplitude Fourier
term in the long-period fit to
the c-band data (fp-powerterm-c)
(1)
571- 581 I11 --- fp-power-o [-2016320490/2071847958] Highest
amplitude Fourier term in the
long-period fit to the o-band data
(fp-powerterm-o) (1)
583- 593 F11.6 d fp-domper-c [0.000153/1500] Period corresponding
to fp-powerterm-c
595- 605 F11.6 d fp-domper-o [-0.000008/1499.992432]? Period
corresponding to fp-powerterm-o
606 A1 --- f_fp-domper-o [I] I for infinity
608 I1 --- fp-fit [0/1] Was a short-period fit
performed? (0=no, 1=yes)
(fp-shortfit) (1)
610- 618 F9.6 d fp-period [0/29.9995]?=0 Final master period
from the short-period Fourier fit
(1)
620- 627 F8.6 mag fp-fitrms [0/1.57105]?=0 rms scatter from the
final short-period fit
629- 639 F11.6 --- fp-fitchi [0/4959.91]?=0 Χ2/N for the
short-period Fourier fit
641 I1 --- fp-Nfours [0/6]?=0 Number of Fourier terms
used in the short-period fit
(fp-fournum) (1)
643- 646 F4.1 --- fp-alias [-3/3]?=0 Diurnal alias j of the
final period relative to fp-LSper
(see Equation (4), Section 3.4)
648 I1 --- fp-mult [0/6]?=0 Multiplication factor f of
the final period relative to
fp-LSper (see Equation (4),
Section 3.4) (fp-multfac)
650- 658 F9.6 --- fp-phaseoff [-5.975/2]?=0 Offset of the final
period relative to fp-LSper, in
cycles over the full temporal span
of our data
660- 669 F10.6 mag fp-min-c [-30/20.4622]?=0 Minimum brightness
reached by the short-period fit to
the c-band photometry at any time
corresponding to an actual
measurement (1)
671- 679 F9.6 mag fp-max-c [0/50]?=0 Maximum brightness reached
by the short-period fit to the
c-band photometry at any time
corresponding to an actual
measurement (1)
681- 690 F10.6 mag fp-min-o [-30/19.4405]?=0 Minimum brightness
reached by the short-period fit to
the o-band photometry at any time
corresponding to an actual
measurement (1)
692- 700 F9.6 mag fp-max-o [0/50]?=0 Maximum brightness reached
by the short-period fit to the
o-band photometry at any time
corresponding to an actual
measurement (1)
702- 709 F8.6 mag fp-fitrms-c [0/2.1455]?=0 rms scatter of
residuals from the short-period fit
to the c-band data (1)
711- 718 F8.6 mag fp-fitrms-o [0/1.82797]?=0 rms scatter of
residuals from the short-period fit
to the o-band data (1)
720- 730 E11.6 --- fp-fitchi-c [0/4920.98]?=0 Χ2/N for the
short-period Fourier fit to
the c-band data
732- 742 E11.6 --- fp-fitchi-o [0/5625.9]?=0 Χ2/N for the
short-period Fourier fit to
the o-band data
744- 754 F11.6 mag fp-const-c [-940.908/4534.28]?=0 Constant term
in the short-period fit to the
c-band data (1)
756- 766 E11.6 mag fp-const-o [-942.724/4534.26]?=0 Constant term
in the short-period fit to the
o-band data (1)
768- 779 E12.6 mag fp-sin1 [-2029.7/1303.39]?=0 Sine
coefficient of the first Fourier
term in the short-period fit (3)
781- 792 E12.6 mag fp-cos1 [-1164.18/7578.69]?=0 Cosine
coefficient of the first Fourier
term in the short-period fit (3)
794- 802 E9.6 --- fp-PPFAPshort1 [0/41]?=0 PPFAP of residuals after
subtraction of the best
short-period Fourier fit with one
term (2)
804- 815 E12.6 mag fp-sin2 [-2540.77/1245.46]?=0 Sine
coefficient of the second Fourier
term in the short-period fit (3)
817- 827 E11.6 mag fp-cos2 [-634.503/4398.58]?=0 Cosine
coefficient of the second Fourier
term in the short-period fit (3)
829- 837 E9.6 --- fp-PPFAPshort2 [0/41]?=0 PPFAP of residuals after
subtraction of the best
short-period Fourier fit with two
terms (2)
839- 850 E12.6 mag fp-sin3 [-1667.47/495.677]?=0 Sine
coefficient of the third Fourier
term in the short-period fit (3)
852- 862 E11.6 mag fp-cos3 [-484.095/1663.08]?=0 Cosine
coefficient of the third Fourier
term in the short-period fit (3)
864- 872 E9.6 --- fp-PPFAPshort3 [0/41]?=0 PPFAP of residuals after
subtraction of the best
short-period Fourier fit with three
terms (2)
874- 884 E11.6 mag fp-sin4 [-616.885/221.102]?=0 Sine
coefficient of the fourth Fourier
term in the short-period fit (3)
886- 896 E11.6 mag fp-cos4 [-287.216/352.483]?=0 Cosine
coefficient of the fourth Fourier
term in the short-period fit (3)
898- 906 E9.6 --- fp-PPFAPshort4 [0/41]?=0 PPFAP of residuals after
subtraction of the best
short-period Fourier fit with four
terms (2)
908- 918 E11.6 mag fp-sin5 [-173.413/83.6868]?=0 Sine
coefficient of the fifth Fourier
term in the short-period fit (3)
920- 929 E10.6 mag fp-cos5 [-60.0101/82.5777]?=0 Cosine
coefficient of the fifth Fourier
term in the short-period fit (3)
931- 939 E9.6 --- fp-PPFAPshort5 [0/41]?=0 PPFAP of residuals after
subtraction of the best
short-period Fourier fit with five
terms (2)
941- 950 E10.6 mag fp-sin6 [-32.4282/9.5854]?=0 Sine
coefficient of the sixth Fourier
term in the short-period fit (3)
952- 961 E10.6 mag fp-cos6 [-55.3204/9.23645]?=0 Cosine
coefficient of the sixth Fourier
term in the short-period fit (3)
963- 971 E9.6 --- fp-PPFAPshort6 [0/41]?=0 PPFAP of residuals after
subtraction of the best
short-period Fourier fit with six
terms (2)
973- 982 F10.6 --- fp-hifreq [0/690.006]?=0 A measure of the
relative power in the
high-frequency vs. low-frequency
terms in the short-period Fourier
fit
984- 995 F12.6 --- fp-timerev [0/18088.5]?=0 A measure of the
degree of invariance of the
short-period Fourier fit with
respect to a reversal (i.e.,
mirroring) of the time axis about
the time of minimum light
(large value=invariant) (1)
997-1006 F10.6 --- fp-phase180 [0/344.646]?=0 A measure of the
degree of invariance of the
short-period Fourier fit with
respect to a 180° phase shift
(large value=invariant) (1)
1008 I1 --- fp-power [0/6]?=0 Highest amplitude Fourier
term in the short-period fit
(fp-powerterm) (1)
1010-1018 F9.6 d fp-domperiod [0/29.9995]?=0 Period corresponding
to fp-powerterm
1020-1022 I3 --- vf-Nc [1/372] Number of c-band
observations
1024-1026 I3 --- vf-No [1/420] Number of o-band
observations
1028-1033 F6.3 mag vf-c-med [9.501/19.995] Weighted median
c magnitude (1)
1035-1040 F6.3 mag vf-o-med [8.246/19.005] Weighted median
o magnitude (1)
1042-1047 F6.3 mag vf-per5 [-9.047/-0.009] 5th percentile of
median-subtracted magnitudes (1)
1049-1054 F6.3 mag vf-per10 [-6.935/-0.007] 10th percentile of
median-subtracted magnitudes (1)
1056-1061 F6.3 mag vf-per25 [-4.431/-0.002] 25th percentile of
median-subtracted magnitudes (1)
1063-1067 F5.3 mag vf-per75 [0.003/5.136] 75th percentile of
median-subtracted magnitudes (1)
1069-1073 F5.3 mag vf-per90 [0.007/6.197] 90th percentile of
median-subtracted magnitudes (1)
1075-1079 F5.3 mag vf-per95 [0.009/6.282] 95th percentile of
median-subtracted magnitudes (1)
1081-1087 F7.3 --- vf-Hday [-6.472/610.677] A statistic probing
the significance of intranight
variations (1)
1089-1096 F8.2 --- vf-Hlong [0/23856] A statistic probing the
significance of internight
(long-term) variations (1)
1098-1102 F5.3 --- vf-wsd [0.007/3.899] Weighted standard
deviation (4)
1104-1108 F5.3 --- vf-iqr [0.008/6.173] Interquartile range
(4)
1110-1118 F9.3 --- vf-chin [0.181/12738.3] Reduced
Χ2=Χ2/(N-1) (1) (4)
1120-1125 F6.3 --- vf-roms [0.281/83.186] Robust median
statistic (1) (4)
1127-1134 E8.5 --- vf-nxs [-0.03235/25.7368] Normalized excess
variance (4)
1136-1140 F5.3 --- vf-nppa [0/0.363] Normalized peak-to-peak
amplitude (4)
1142-1148 F7.3 --- vf-inu [0.305/136.35] Inverse von Neumann
ratio (1) (4)
1150-1158 F9.3 --- vf-WS-I [-26.432/12705.5] Welch-Stetson I
(1) (4)
1160-1166 F7.3 --- vf-S-J [-5.725/124.856] Stetson J (1) (4)
1168-1172 F5.3 --- vf-S-K [0.088/0.968] Stetson K (4)
1174-1176 I3 --- df-Ndet [0/791] Number of detections at this
location in the difference images
(df-numdet)
1178-1182 F5.2 mag df-medmag [0/29.16] Median magnitude of
detections in the difference images
(5)
1184-1188 F5.2 mag df-meanmag [0/29.16] Mean magnitude of
detections in the difference images
(5)
1190-1196 F7.2 --- df-medsig [0/1000] Median S/N of detections
in the difference images
1198-1204 F7.2 --- df-meansig [0/1000] Mean S/N of detections in
the difference images
1206-1212 F7.2 --- df-r2sig [0/1000] S/N of the secondmost
significant difference image
detection
1214-1220 F7.2 --- df-r1sig [0/1000] S/N of the most significant
difference image detection
1222-1227 F6.2 --- df-medchin [0/997.73] Median Χ2/N of PSF
fits on the difference images
1229-1231 I3 --- df-Nbright [0/632] Number of positive-going
detections on the difference images
(df-numbright)
1233-1237 F5.1 --- df-medPvar [0/999] Median value of Pvr
(probability of being a variable
star) from vartest
1239-1243 F5.1 --- df-meanPvar [0/999] Mean value of Pvr
1245-1247 I3 --- df-r2Pvar [0/999] Second highest value of Pvr
1249-1251 I3 --- df-r1Pvar [0/999] Highest value of Pvr
1253-1257 F5.1 --- df-medPscar [0/999] Median value Psc
(probability of being a star
subtraction residual) from vartest
1259-1263 F5.1 --- df-meanPscar [0/999] Mean value Psc (probability
of being a star subtraction
residual) from vartest
1265-1268 F4.1 arcsec ps-dist [0.6/60]?=99.9 Angular distance to
the nearest star in our Pan-STARRS
reference catalog
1270-1273 F4.1 arcsec ps-dist0 [0.6/60]?=99.9 Angular distance to
the nearest star in our Pan-STARRS
reference catalog that is at least
equally bright
1275-1278 F4.1 arcsec ps-dist2 [1.2/60]?=99.9 Angular distance to
the nearest star in our Pan-STARRS
reference catalog that is at least
two magnitudes brighter
1280-1283 F4.1 arcsec ps-dist4 [1.9/60]?=99.9 Angular distance to
the nearest star in our Pan-STARRS
reference catalog that is at least
four magnitudes brighter
1285-1287 I3 --- ls-Npt [100/692] Number of photometric
measurements input to lombscar
1289-1291 I3 --- ls-Nuse [12/691] Number of photometric
measurements lombscar identified as
good
1293-1298 F6.3 mag ls-c-med [1.132/27.226] Median c-band
magnitude calculated by lombscar
1300-1305 F6.3 mag ls-o-med [-8.752/64.347] Median o-band
magnitude calculated by lombscar
1307-1317 F11.6 d ls-Pday [0.038263/3540.18] Period output by
lombscar
1319-1325 F7.3 --- ls-PPFAP [0/114.048] PPFAP from Lomb-Scargle
periodogram in lombscar (2)
1327-1332 F6.3 --- ls-Chin [0.008/37.232] Χ2/N for the
Fourier+polynomial fit performed
by lombscar
1334-1341 F8.3 --- ls-Cchin [0.055/1529.44] Χ2/N for the
constant-magnitude fit performed
by lombscar
1343-1349 F7.3 --- ls-Pchin [0.053/239.199] Χ2/N for the
polynomial-only fit performed by
lombscar
1351-1358 F8.3 --- ls-Xchin [0.172/1504.22] Χ2/N for the
polynomial-only fit performed by
lombscar, without outlier trimming
1360-1365 F6.4 --- ls-Fraclo [0/0.6763] Fraction of points with
magnitudes more than 5σ below
the median
1367-1372 F6.4 --- ls-Frachi [0/0.6897] Fraction of points with
magnitudes more than 5σ above
the median
1374-1379 F6.3 --- ls-txclo [-0.694/0.992] Fraction of low
outliers with time difference less
than 0.06 days
1381-1386 F6.3 --- ls-txchi [-0.694/0.992] Fraction of high
outliers with time difference less
than 0.06 days
1388-1396 F9.3 --- ls-Chin-minus-1 [0.013/40784.3] Χ2/N for the
lombscar Fourier fit to j=-1 alias
1398-1407 F10.3 --- ls-Chin-minus-h [0.016/216941] Χ2/N for the
lombscar Fourier fit to j=-0.5
alias
1409-1414 F6.3 --- ls-Chin-plus-h [0.013/86.651] Χ2/N for the
lombscar Fourier fit to j=+0.5
alias
1416-1422 F7.3 --- ls-Chin-plus-1 [0.014/123.748] Χ2/N for the
lombscar Fourier fit to j=+1 alias
1424-1430 F7.3 mag/yr ls-Ply1 [-26.434/16.03] Linear coefficient
of the polynomial fit by lombscar
1432-1438 F7.3 mag/yr2 ls-Ply2 [-70.895/221.363] Quadratic
coefficient of the polynomial fit
by lombscar
1440-1444 F5.3 --- ls-Phgap [0.007/0.875] Biggest time gap with
no points in the folded light curve
(fraction of ls-Pday)
1446 I1 --- ls-D [0/1] Period doubling (6)
1448-1458 F11.3 --- ls-RMS [0.003/1.233053e+06] rms of
residuals from lombscar Fourier fit
1460-1465 F6.3 --- ls-F0 [-0.742/0.858] Amplitude of lombscar
constant Fourier term divided by
rms
1467-1472 F6.3 --- ls-F1cos [-0.948/0.935] Amplitude of lombscar
cos1 Fourier term divided by rms
1474-1479 F6.3 --- ls-F1sin [-0.952/0.951] Amplitude of lombscar
sin1 Fourier term divided by rms
1481-1486 F6.3 --- ls-F2cos [-0.999/0.999] Amplitude of lombscar
cos2 Fourier term divided by rms
1488-1493 F6.3 --- ls-F2sin [-0.999/0.999] Amplitude of lombscar
sin2 Fourier term divided by rms
1495-1500 F6.3 --- ls-F3cos [-0.902/0.9] Amplitude of lombscar
cos3 Fourier term divided by rms
1502-1507 F6.3 --- ls-F3sin [-0.943/0.937] Amplitude of lombscar
sin3 Fourier term divided by rms
1509-1514 F6.3 --- ls-F4cos [-0.898/0.903] Amplitude of lombscar
cos4 Fourier term divided by rms
1516-1521 F6.3 --- ls-F4sin [-0.962/0.958] Amplitude of lombscar
sin4 Fourier term divided by rms
1523-1529 A7 --- Class Final ATLAS variable classification
(7)
1531 I1 --- ddc [0/1] Difference image statistic
(1=probably variable independent of
any other information) (ddcSTAT)
1533 I1 --- prox [0/1] Proximity statistic
(1=variability detection probably
not caused by blending) (proxSTAT)
1535-1553 F19.17 --- P(CBF) [0/1] Machine classifier probability
that this star is in the CBF
category
1555-1573 F19.17 --- P(CBH) [0/1] Machine classifier probability
that this star is in the CBH
category
1575-1593 F19.17 --- P(DBF) [0/1] Machine classifier probability
that this star is in the DBF
category
1595-1613 F19.17 --- P(DBH) [0/1] Machine classifier probability
that this star is in the DBH
category
1615-1633 F19.17 --- P(HARD) [0/1] Machine classifier probability
that this star is IRR, LPV,
or "dubious"
1635-1653 F19.17 --- P(MIRA) [0/1] Machine classifier probability
that this star is in the MIRA
category
1655-1673 F19.17 --- P(MPULSE) [0/1] Machine classifier probability
that this star is in the MPULSE
category
1675-1693 F19.17 --- P(MSINE) [0/1] Machine classifier probability
that this star is in the MSINE
category
1695-1713 F19.17 --- P(NSINE) [0/1] Machine classifier probability
that this star is in the NSINE
category
1715-1733 F19.17 --- P(PULSE) [0/1] Machine classifier probability
that this star is in the PULSE
category
1735-1753 F19.17 --- P(SINE) [0/1] Machine classifier probability
that this star is in the SINE
category
1755-1773 F19.17 --- P(IRR) [0/1] Machine classifier probability
that this star is in the IRR
category
1775-1793 F19.17 --- P(LPV) [0/1] Machine classifier probability
that this star is in the LPV
category
1795-1813 F19.17 --- P(dubious) [0/1] Machine classifier probability
that this star is in the "dubious"
category
1815-1820 F6.3 mag gmag [3.61/23.297] Pan-STARRS1 DR1 g-band
magnitude
1822-1826 F5.3 mag e_gmag [0/0.333] Uncertainty gmag
1828-1833 F6.3 mag rmag [4.12/21.866] Pan-STARRS1 DR1 r-band
magnitude
1835-1839 F5.3 mag e_rmag [0/0.333] Uncertainty on rmag
1841-1846 F6.3 mag imag [4.49/20.516] Pan-STARRS1 DR1 i-band
magnitude
1848-1852 F5.3 mag e_imag [0/0.333] Uncertainty on imag
1854-1859 F6.3 mag zmag [4.11/20.434]?=-9.999 Pan-STARRS1
DR1 z-band magnitude
1861-1865 F5.3 mag e_zmag [0/0.333]?=9.999 Uncertainty on zmag
1867-1872 F6.3 mag ymag [4.31/20.145]?=-9.999 Pan-STARRS1
DR1 Y-band magnitude
1874-1878 F5.3 mag e_ymag [0/0.333]?=9.999 Uncertainty on ymag
1880-1892 A13 --- starID Old version of the ATLAS star
identifier (historical interest
only)
1894-1911 I18 --- objID Object identifier, useful for
linkage with the "detection"
database
--------------------------------------------------------------------------------
Note (1): Used for machine classification.
Note (2): For convenience, we will refer to -log10(FAP) as PPFAP, meaning
"power of the periodogram FAP".
Note (3): Used for machine classification after conversion of sine and cosine
coefficients to an overall amplitude and phase (see Equations (6) and (7),
Section 4.).
Equation (6): fm(t)=amsin(m.(2πt/P))+bmcos(m.(2πt/P));
Equation (7): fm(t)=dmcos(m((2πt/P)-Φm)).
Note (4): Sokolovsky et al. 2017MNRAS.464..274S.
Note (5): Negative-going detections are included by calculating magnitudes from
the absolute value of the flux.
Note (6): Period doubling as follows:
1 = The lombscar output period has been doubled relative to the highest peak
in the Lomb-Scargle periodogram;
0 = The lombscar output period has not been doubled relative to the highest
peak in the Lomb-Scargle periodogram.
Note (7): Classification as follows:
CBF = Close binary, full period. These stars are contact or near-contact
eclipsing binaries for which the Fourier fit has found the correct
period and hence fit the primary and secondary eclipses separately;
CBH = Close binary, half period. These stars are contact or near-contact
eclipsing binaries for which the Fourier fit has settled on half the
correct period and hence has overlapped the primary and secondary
eclipses. Physically, the CBF and CBH stars are expected to differ
in that the primary and secondary eclipses are likely to be more
similar in depth in the latter class;
DBF = Distant binary, full period. These stars are detached eclipsing
binaries for which the Fourier fit has found the correct period and
hence fit the primary and secondary eclipses separately;
DBH = Distant binary, half period. These stars are fully detached
eclipsing binaries for which the Fourier fit has settled on half the
correct period and hence has overlapped the primary and secondary
eclipses;
IRR/LPV = The acronyms stand for "long-period" and "irregular" variables.
These classes serve as "catch-all" bins for objects that do not seem
to fit into any of our more specific categories. The LPV class
contains objects whose variations appear to be dominated by low
frequencies, corresponding to P≳5 days, while the IRR class
contains objects whose dominant frequencies are higher. Most of the
stars classified as LPV or IRR (especially the latter) do not show
coherent variations that can be folded cleanly with a single period.
Hence, both classes are in some sense "irregular," though the
characteristic timescales are different. Among the objects that
cannot be cleanly phased to a single period, the LPV class surely
includes many semiregular red giant variables, while the IRR class
has a large number of cataclysmic binaries;
MIRA = Mira variables. These stars are a subset of the LPV's that have
photometric amplitudes exceeding 2.0 mag in either the cyan or
orange filter. They generally show coherent periodicity, but the
two-year temporal baseline of our data may in many cases be
insufficient to solve for the period accurately;
MPULSE = Stars showing modulated pulsation, such that the Fourier fit has
settled on a period double or triple the actual pulsation, in order
to render multiple pulses of different amplitudes or shapes. These
objects could be multimodal or Blazhko-effect stars, or stars
exhibiting some other kind of variability in addition to their
pulsations;
MSINE = Stars showing modulated sinusoids. These are exactly analogous to
the MPULSE stars, except that instead of a classic sawtooth pulse
light curve, the fundamental waveform being modulated is a simple
sinusoid. Thus, MSINE stars may show two, three, four, five, or even
six cycles through the Fourier fit. Each cycle appears to be a good
approximation to a sine wave, but the amplitude and/or mean
magnitude varies from one to the next. Physically, the MSINE stars
may include spotted ellipsoidal variables, rotating stars with
evolving spots, and sinusoidal pulsators such as RR Lyrae (RRC)
stars that have multiple modes or multiple types of variability;
NSINE = Sinusoidal variables with much residual noise or with evidence of
additional variability not captured in the fit. Many spotted
rotators with evolving spots likely fall into this class, as well as
faint or low-amplitude δ Scuti stars and ellipsoidal
variables;
PULSE = Pulsating stars showing the classic sawtooth light curve, regardless
of period. They are expected to include both RR Lyrae and
δ Scuti stars, and some Cepheids. These classes are resolvable
based on period, color, amplitude, and the phase offsets of the
various Fourier terms;
SHAV = These are the slow high-amplitude variables, an extremely rare class
with long periods and Mira-like amplitudes, but with color
insufficiently red for a true Mira. Only 17 of these were identified
in our entire catalog. They include AGNs, R Coronae Borealis stars,
and at least one apparent nova;
SINE = Sinusoidal variables. These stars exhibit simple sine-wave
variability with little residual noise. Ellipsoidal variables likely
dominate this class;
STOCH = These are the variables that do not fit into any coherent periodic
class, not even IRR. They would be classified as "dubious" except
that they have ddcSTAT=1, meaning that detections on the difference
images demonstrate their genuine variability. Their physical nature
is unclear, but many of them do appear to exhibit highly significant
stochastic variations with very little coherence on the timescales
probed by ATLAS;
dubious = Star might not be a real variable.
--------------------------------------------------------------------------------
History:
From electronic version of the journal(End) Tiphaine Pouvreau [CDS] 09-May-2019
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