J/AJ/163/263 323 YSOs properties with ZTF (Hillenbrand+, 2022)
A Zwicky Transient Facility Look at Optical Variability of Young Stellar Objects
in the North America and Pelican Nebulae Complex.
Hillenbrand L.A., Kiker T.J., Gee M., Lester O., Braunfeld N.L.,
Rebull L.M., Kuhn M.A.
<Astron. J., 163, 263 (2022)>
=2022AJ....163..263H 2022AJ....163..263H
ADC_Keywords: YSOs; Stars, pre-main sequence; Photometry, VRI
Keywords: Young star clusters ; Pre-main sequence stars ; T Tauri stars
; Slow irregular variable stars ; Stellar rotation ; Time
domain astronomy
Abstract:
We present a study of 323 photometrically variable young stellar
objects that are likely members of the North America and Pelican
nebulae star-forming region. To do so, we utilize over two years of
data in the g and r photometric bands from the Zwicky Transient
Facility. We first investigate periodic variability, finding 46
objects (∼15% of the sample) with significant periods that phase well
and can be attributed to stellar rotation. We then use the
quasiperiodicity (Q) and flux asymmetry (M) variability metrics to
assign morphological classifications to the remaining aperiodic light
curves. Another ∼39% of the variable star sample beyond the periodic
(low Q) sources are also flux-symmetric, but with a quasiperiodic
(moderate Q) or stochastic (high Q) nature. Concerning flux-asymmetric
sources, our analysis reveals ∼14% bursters (high negative M) and ∼29%
dippers (high positive M). We also investigate the relationship
between variability slopes in the g versus g-r color-magnitude
diagram, and the light-curve morphological classes. Burster-type
objects have shallow slopes, while dipper-type variables tend to have
higher slopes that are consistent with extinction-driven variability.
Our work is one of the earliest applications of the Q and M metrics to
ground-based data. We therefore contrast the Q values of high-cadence
and high-precision space-based data, for which these metrics were
designed, with Q determinations resulting from degraded space-based
light curves that have the cadence and photometric precision
characteristic of ground-based data.
Description:
The Zwicky Transient Facility (ZTF) employs the 48inch Schmidt
telescope at Palomar Observatory and possesses a camera with a
47deg2 field of view. In this paper, we analyze data from the fourth
public ZTF data release (ZTF DR4), which corresponds to more than two
years of data taken in the North America and Pelican (NAP) field
between 2018 March 28 and 2020 June 6. We focus our analysis on the
ZTF g-band (λ=4722Å) and r-band (λ=6340Å) data, as
the long-term i-band survey mainly covers high-galactic-latitude
fields.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 92 323 Properties of variable stars in our NAP sample
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/AJ/121/3160 : JHK photometry near the Trapezium region (Carpenter+, 2001)
J/A+A/396/513 : Stellar Rotation in the Orion Nebula Cluster (Herbst+, 2002)
J/ApJ/697/787 : The NAN complex. I. IRAC observations (Guieu+, 2009)
J/A+A/520/A15 : RACE-OC project; YSOs within 100pc (Messina+, 2010)
J/ApJ/733/50 : Mid-IR photo. monitoring of the ONC (Morales-Calderon+, 2011)
J/ApJS/193/25 : The NAN complex. II. MIPS observations (Rebull+, 2011)
J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)
J/AJ/148/122 : YSOVAR; infrared photometry in Lynds 1688 (Gunther+, 2014)
J/A+A/568/A49 : Long-term photometry of pre-MS stars (Poljancic Beljan+, 2014)
J/other/PASA/32.21 : Long-Term Multicolour Photometry of YSOs (Ibryamov+, 2015)
J/AJ/150/118 : YSOVAR IR photometry in IRAS 20050+2720 (Poppenhaeger+, 2015)
J/AJ/150/145 : YSOVAR infrared photometry in GGD12-15 (Wolk+, 2015)
J/A+A/602/A115 : X-ray survey of NGC7000/IC5070 (Damiani+, 2017)
J/ApJ/848/97 : Young stellar variables with KELT for K2 I. (Rodriguez+, 2017)
J/AJ/156/71 : K2 Campaign 2 young disk-bearing stars Sco & Oph (Cody+, 2018)
J/other/RAA/18.137 : Long-term BVRI photometry 15 PMS stars (Ibryamov+, 2018)
J/AJ/156/275 : Rotational evolution young, binary M dwarfs (Stauffer+, 2018)
J/A+A/627/A135 : VRI photometry of IC5070 variable stars (Bhardwaj+, 2019)
J/ApJ/886/152 : ZTF early observations of Type Ia SNe. I. LCs (Yao+, 2019)
J/ApJ/902/48 : ZTF early observations type Ia supernovae. III. (Bulla+, 2020)
J/ApJ/904/140 : Ruprecht 147 members & rot. data 5 other cl. (Curtis+, 2020)
J/ApJ/904/146 : Young stars in North America & Pelican Nebulae (Fang+, 2020)
J/ApJ/899/128 : Validated & new members NGC7000/IC5070 Complex (Kuhn+, 2020)
J/ApJ/902/47 : ZTF early obs. of type Ia SNe. II. Rise time (Miller+, 2020)
J/AJ/159/198 : Cataclysmic variables in ZTF 1yr (2018-2019) (Szkody+, 2020)
J/AJ/161/15 : Light curve of the dwarf nova AT 2020iko (Soraisam+, 2021)
J/AJ/162/101 : K2 ugri & Hα photometry in Lagoon Nebula (Venuti+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- Name Identifier (1)
30- 38 F9.5 deg RAdeg [311/316] ICRS Right Ascension, decimal degrees (2)
40- 47 F8.5 deg DEdeg [42/46] ICRS Declination, decimal degrees (2)
49- 55 F7.3 d Tscale [0.83/236]? Timescale or Period, days (3)
57- 60 F4.2 --- Q [0.11/1] lightcurve quasiperiodicity metric defined
in Equation 2
62- 66 F5.2 --- M [-1.2/1.11] lightcurve asymmetry metric defined in
Equation 3
68- 73 F6.4 --- nu [0.004/0.12] variability metric, Equation 1 (4)
75- 79 F5.2 mag rmag [12.4/19.4] mean magnitude over ZTF time series
81- 83 A3 --- Pri Primary variability class (5)
85- 87 A3 --- Sec Secondary variability class (5)
89- 92 F4.1 deg CMDang [7.5/98.4]? Fitted slope to the g vs g-r
color-magnitude diagram (6)
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Note (1): Source identifiers were adopted as follows:
LkH? = Herbig, 1958ApJ...128..259H 1958ApJ...128..259H
V* = General Catalog of Variable Stars, Samus+, 2017, B/gcvs and
2021OAst...30..122S 2021OAst...30..122S
FHK = Fang+, 2020, J/ApJ/904/146F
2MASS = Cutri+, 2003tmc..book.....C 2003tmc..book.....C
GaiaDR2 = Gaia Collaboration+, 2018, I/345
Note (2): ICRS positions from Gaia DR2, where available.
Note (3): Timescale or Period is the Lomb-Scargle periodogram peak that is
identified with a period when the Primary Var. Class column (Pri) is "P";
otherwise interpreted as a variability timescale and not a strict period.
Tscale is given as a null ("") when no significant peak was present.
Note (4): Equation 1 as featured in Sokolovsky+, 2017MNRAS.464..274S 2017MNRAS.464..274S.
Note (5): Primary Variability Class ("Pri") is dominant behavior in the
lightcurve, while Secondary Variability Class ("Sec") is an additional,
subordinate behavior exhibited in the lightcurve. A null value for the
"Sec" means that no secondary lightcurve classification was identified
for the source, only a primary classification.
p = strictly periodic;
mp = multi-periodic;
qps = quasiperiodic, symmetric;
qpd = quasiperiodic, dipping;
apd = aperiodic, dipping;
b = Burster;
s = stochastic or aperiodic, symmetric behavior;
l = Long timescale objects;
u = unclassifiable.
Note (6): CMD Angle ("CMDang") is reported only when the error is <10degrees.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 27-Sep-2022