J/AJ/170/54 INT monitoring of Local Grp. VII. IC 10 photometry (Gholami+, 2025)
The Isaac Newton Telescope monitoring survey of Local Group dwarf galaxies.
VII. Long-period variable stars in the nearest starburst dwarf galaxy, IC 10.
Gholami M., Javadi A., Mahani H., van Loon J.T., Khosroshahi H.,
Saremi E., McDonald I., Eftekhari S., Ren Yi, Altafi H.
<Astron. J., 170, 54 (2025)>
=2025AJ....170...54G 2025AJ....170...54G
ADC_Keywords: Stars, variable; Galaxies, dwarf; Photometry; Optical;
Galaxies, nearby; Local group
Keywords: Local Group ; Asymptotic giant branch stars ; Stellar populations
Abstract:
To identify long-period variable (LPV) stars in IC 10-the nearest
starburst galaxy of the Local Group-we conducted an optical monitoring
survey using the 2.5m Isaac Newton Telescope with the wide-field
camera (WFC) in the i band and V band from 2015 to 2017. We created a
photometric catalog for 53,579 stars within the area of CCD4 of WFC
(∼0.07deg2 corresponding to 13.5kpc2 at the distance of IC 10), of
which we classified 536 and 380 stars as LPV candidates, mostly
asymptotic giant branch (AGBs) stars and red supergiants, within CCD4
and two half-light radii of IC 10, respectively. By comparing our
output catalog to the catalogs from Pan-STARRS, Spitzer Space
Telescope, Hubble Space Telescope (HST), and carbon stars from the
Canada- France-Hawai'i Telescope survey, we determined the success of
our detection method. We recovered ∼73% of Spitzer's sources in our
catalog and demonstrated that our survey successfully identified 43%
of the variable stars found with Spitzer, and also retrieved 40% of
the extremely dusty AGB stars among the Spitzer variables. In
addition, we successfully identified ∼70% of HST variables in our
catalog. Furthermore, we found all the confirmed LPVs that Gaia DR3
detected in IC 10 among our identified LPVs. This paper is the first
in a series on IC 10, presenting the variable star survey methodology
and the photometric catalog, available to the public through the
Centre de Donnees Astronomiques de Strasbourg.
Description:
We conducted imaging with the 2.5m Isaac Newton Telescope at the
Observatorio del Roque de Los Muchachos (La Palma), covering nine
epochs spaced a few months apart between 2015 June and 2017 October,
with cadences for an expected period to adequately identify LPVs. We
used the WFC, which is an optical mosaic camera containing four
2048x4096 pixels CCDs with a pixel size of 0.33". The observations
were performed in the Sloan i (763nm) and Harris V (542nm) filters,
except for the night of 2015 June 21, which used the Landolt I (810nm)
filter.
Objects:
--------------------------------------------------
RA (2000) DE Designation(s)
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00 20 17.33 +59 18 13.6 IC 10 = LEDA 1305
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 112 53579 The photometric catalog and mean properties of
sources
table4.dat 47 696527 The light curve information
figa1/* . 40 Light curves in JPG format (Figure A1)
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/ApJ/697/1993 : Spitzer study of AGB stars. III. (Boyer+, 2009)
J/MNRAS/411/263 : JHK variable stars in M33 (Javadi+ 2011)
J/AJ/144/4 : Propert. of dwarf gal. in the Local Group (McConnachie+, 2012)
J/ApJ/753/71 : Mass-loss return from LMC evolved stars. VI. (Riebel+, 2012)
J/ApJ/754/35 : Red supergiant stars in the SMC. II. (Yang+, 2012)
J/ApJ/797/44 : Evolution and nucleosynthesis of AGB stars (Fishlock+, 2014)
J/ApJ/789/23 : Properties of SN host galaxies (Kelly+, 2014)
J/ApJS/216/10 : DUSTiNGS. I. The Good Source Catalog (Boyer+, 2015)
J/ApJ/800/51 : DUSTiNGS II. Metal-poor dusty AGB stars (Boyer+, 2015)
J/MNRAS/447/3973 : UKIRT M33 monitoring project. IV. WFCAM obs. (Javadi+, 2015)
J/ApJ/804/123 : Star clusters in IC 10 (Lim+, 2015)
J/A+A/630/A92 : The Hubble Catalog of Variables (Bonanos+, 2019)
J/ApJ/877/49 : DUSTiNGS. V. 3.6 and 4.5um light curves (Goldman+, 2019)
J/ApJ/894/135 : INT monitoring of Local Group. I. Andromeda I (Saremi+, 2020)
J/ApJ/923/232 : Red supergiants in 12 Local Group galaxies (Ren+, 2021)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID [93/217615] Star number
8- 14 F7.4 mag Vmag [12.4/25.7]?=99.999 Mean V-band magnitude
16- 21 F6.4 mag e_Vmag [7e-4/1.4]?=9.9999 Uncertainty in Vmag
23- 28 F6.3 mag imag [12/23.6]?=99.999 Mean i-band magnitude
30- 35 F6.4 mag e_imag [7e-4/1.4]?=9.9999 Uncertainty in imag
37- 42 F6.3 --- chi [0.04/44.5] Mean χ value from DAOPHOT
44- 50 F7.3 --- Sharp [-41.9/84.9] Mean sharpness from DAOPHOT
52- 57 F6.3 --- Jvar [-6.2/40.4] Variability index J
59- 63 F5.3 --- Kvar [0/1] Kurtosis index K
65- 70 F6.3 --- Lvar [-5.7/35.6] Variability index L
72- 76 F5.3 mag iAmp [0/3.3]? Amplitude in i-band for Long-Period
Variables
78- 92 A15 --- Status Variability status (1)
94-101 F8.6 deg RAdeg [4.6/5.5] Right ascension (J2000)
103-110 F8.5 deg DEdeg [59.2/59.4] Declination (J2000)
112-112 A1 --- Flag Source flag (2)
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Note (1): Variability status as follows:
Foreground star = 3935 occurrences
LPV-candidate = 536 occurrences; Long-Period Variable candidate
non-LPV = 492 occurrences; not a Long-Period Variable
non-variable = 48616 occurrences
Note (2): Flag as follows:
* = cannot be classified as either foreground stars or IC 10 sources
due to the quality of the astrometric solution (24 occurrences)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID [93/217615] Star number
8- 14 F7.2 d HJD [7552/8035] Heliocentric Julian Date - 2450000
16- 16 A1 --- Filter Filter identifier (1)
18- 23 F6.3 mag mag [11.8/26]?=99.999 Apparent magnitude in Filter
25- 30 F6.4 mag e_mag [1.3e-3/0.7]?=9.9999 Uncertainty in mag
32- 37 F6.3 --- chi [0/68.2] The χ value from DAOPHOT
39- 47 F9.3 --- Sharp [-1568/447.2] The sharpness from DAOPHOT
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Note (1): Filter as follows:
V = V-band (542nm); 321474 occurrences
i = i-band (763nm); 375053 occurrences
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History:
From electronic version of the journal
References:
Saremi et al. Paper I. 2020ApJ...894..135S 2020ApJ...894..135S Cat. J/ApJ/894/135
Saremi et al. Paper II. 2021ApJ...923..164S 2021ApJ...923..164S
Navabi et al. Paper IV. 2021ApJ...910..127N 2021ApJ...910..127N
Parto et al. Paper V. 2023ApJ...942...33P 2023ApJ...942...33P
Abdollahi et al. Paper VI. 2023ApJ...948...63A 2023ApJ...948...63A
Gholami et al. Paper VII. 2025AJ....170...54G 2025AJ....170...54G This catalog
Abdollahi et al. Paper VIII. 2026ApJ..1000...69A 2026ApJ..1000...69A Cat. J/ApJ/1000/69
(End) Prepared by [AAS], Robin Leichtnam [CDS] 07-May-2026