J/A+A/697/A30 Galactic Type II Cepheids gri light curves (Narloch+, 2025)
Period-luminosity relations for Galactic Type II Cepheids in the Sloan bands.
Narloch W., Hajdu G., Pietrzynski G., Wielgorski P., Smolec R., Gieren W.,
Zgirski B., Gorski M., Karczmarek P., Graczyk D.
<Astron. Astrophys. 697, A30 (2025)>
=2025A&A...697A..30N 2025A&A...697A..30N (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, variable ; Photometry, ugriz
Keywords: stars: distances - stars: variables: Cepheids - solar neighborhood
Abstract:
Type II Cepheids (T2Ceps), alongside RR Lyrae stars, serve as
important distance indicators for old Population II stars due to their
period-luminosity (PL) relations. However, few studies of these
relations in the Sloan photometric system have been conducted. Our
goal is to calibrate PL relations (and their counterparts in Wesenheit
magnitudes) in the Sloan-Pan-STARRS gP1rP1iP1 bands for Galactic
T2Ceps located in the vicinity of the Sun. We collected data for 16
T2Ceps of the BL Her type and 17 of the W Vir type using 40 cm
telescopes of the Las Cumbres Observatory Global Telescope Network.
Geometric parallaxes were adopted from Gaia Data Release 3. We have
calibrated PL and period-Wesenheit relations for Milky Way BL Her and
W Vir stars in the solar neighborhood, as well as for a combined
sample of the two types. The relationships derived here will allow the
determination of the distances to the T2Ceps that will be discovered
by the Legacy Survey of Space and Time survey and, in turn, to probe
the extended halo of the Milky Way, as well as the halos of nearby
galaxies. To the best of our knowledge, the relations derived in this
study are the first for Milky Way T2Ceps in the Sloan bands.
Description:
The light curves of 16 BL Her type stars, 17 W Vir stars, 2 RV Tau
stars, 3 pW Vir stars and 1 Type I first-overtone Cepheid from the
vicinity of the Sun were obtained. The data were collected between
2021 August and 2022 July with 14 robotic 40 cm telescopes of the Las
Cumbres Observatory (LCO) Global Telescope Network. Images were taken
with 3Kx2K STL-6303 cameras with the field of view of 29.2'x19.5' and
pixel scale of 0.571"/pix in three Sloan g'r'i' filters. Instrumental
magnitudes were calibrated to the ATLAS All-Sky Stellar Reference
Catalog version 2 (ATLAS-REFCAT2; Tonry et al., 2018ApJ...867..105T 2018ApJ...867..105T,
Cat. J/ApJ/867/105), which is in the Sloan-Pan-STARSS gP1rP1iP1 system
(Tonry et al., 2012ApJ...750...99T 2012ApJ...750...99T).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 282 39 List of studied stars
lc/* . 117 Individual light curves
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See also:
J/MNRAS/471/1447 : Ground-based proper motion of 12 nearby GC (Narloch+, 2017)
J/ApJ/867/105 : ATLAS all-sky stellar ref. catalog, ATLAS-REFCAT2
(Tonry+, 2018)
J/A+A/647/A135 : 35 star clusters and fields in the SMC (Narloch+, 2021)
J/A+A/666/A80 : Star clusters and fields in the LMC (Narloch+, 2022)
J/A+A/689/A138 : Light curves of RR Lyrae in the Sloan bands (Narloch+, 2024)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Star Star name
11- 12 I2 h RAh Simbad right ascension (J2000)
14- 15 I2 min RAm Simbad right ascension (J2000)
17- 21 F5.2 s RAs Simbad right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 33 F4.1 arcsec DEs Declination (J2000)
35- 39 A5 --- VType Variable type (RRLyr, T2Cep or Star)
41- 45 A5 --- Type Type
47- 56 F10.7 d Per AAVSO period
58 A1 --- --- [g]
60- 73 F14.6 d T0g Epoch for g band
75- 76 I2 --- gFSorder FSorder in g band
78 A1 --- --- [r]
80- 93 F14.6 d T0r Epoch for r band
95- 96 I2 --- rFSorder FSorder in r band
98 A1 --- --- [i]
100-113 F14.6 d T0i Epoch for i band
115-116 I2 --- iFSorder FSorder in i band
118-282 A165 --- Com Comments
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Byte-by-byte Description of file (# headlines): lc/*
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Bytes Format Units Label Explanations
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1- 5 F5.3 --- Phase Phase of the light curve
7- 20 F14.6 d HJD Heliocentric Julian Day of the observation
22- 25 A4 --- Tel Telescope used to collect given point
27- 32 F6.3 mag mag Sloan-Pan-STARSS magnitude in Band
34- 39 F6.4 mag e_mag ? Error of the magnitude returned by DAOPHOT (1)
42 A1 --- Band Observed Sloan-Pan-STARSS band (2)
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Note (1): The error of a magnitude was obtained from aperture photometry
performed with DAOPHOT package.
Note (2): g for gP1, r for rP1, i for iP1.
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Acknowledgements:
Weronika Narloch, wnarloch(at)camk.edu.pl
(End) Patricia Vannier [CDS] 27-Mar-2025