J/ApJ/1000/69 INT survey of local dwarf gal. VIII. LPV stars (Abdollahi+, 2026)
The Isaac Newton Telescope monitoring survey of local group dwarf galaxies.
VIII. A census of long-period variable stars across the Andromeda dwarf
satellite system.
Abdollahi H., Javadi A., van Loon J.T., McDonald I., Abdollahi M.,
Saremi E., Khosroshahi H.G., Molnar L., Mahani H.
<Astrophys. J., 1000, 69 (2026)>
=2026ApJ..1000...69A 2026ApJ..1000...69A
ADC_Keywords: Galaxies, nearby; Galaxies, dwarf; Stars, variable; Extinction;
Photometry, VRI; Galaxies, radius
Keywords: Asymptotic giant branch ; Long period variable stars ; Local Group
Abstract:
We present a comprehensive catalog, in the Sloan i and Harris V
filters, of long-period variable (LPV) stars in the spheroidal dwarf
satellites of the Andromeda galaxy based on a dedicated survey for
variable stars in Local Group dwarf systems. Using photometric
time-series data obtained with the Wide Field Camera on the 2.5m
Isaac Newton Telescope, we identify approximately 2800 LPV candidates
across 17 Andromeda satellites, spanning a broad range in luminosity
and variability amplitude. This study is accompanied by a public data
release that includes two comprehensive catalogs, a catalog of the
complete stellar populations for each galaxy, and a separate catalog
listing all identified LPV candidates. Both are available through
CDS/VizieR and provide a valuable resource for investigating quenching
timescales, stellar mass distributions, and the effects of mass loss
and dust production in dwarf galaxies. We derive updated structural
parameters, including newly measured half-light radii, and determine
distance moduli using the tip of the red giant branch method with
Sobel filter edge detection, yielding values between 23.38±0.06
and 25.35±0.06mag.
Description:
The observations in this study are part of the Isaac Newton Telescope
(INT) Survey. A full description of the survey strategy, observational
setup, and data reduction, as well as the number of observations in
each photometric band for each galaxy, is provided in Paper I
(Saremi+ 2020, J/ApJ/894/135).
The observations were carried out using the Wide Field Camera (WFC) on
the 2.5m INT at the Observatorio del Roque de los Muchachos, La Palma.
The WFC consists of four 2048x4096 CCDs with a pixel scale of 0.33"/pix.
Time-series photometry was obtained in the Sloan i (central wavelength
at 7743Å), Harris V (central wavelength 5425Å), and RGO I filters.
The RGO I filter was employed only for the initial epoch of several
targets and is not used in this paper or dataset.
Figure 1 shows the spatial distribution of the 20 observed satellites
around M31. This study provides the initial findings for galaxies
And II, III, V, VI, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX,
XX, XXI, and XXII.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 131 20 Observational properties and half-light radius of
targets
table2.dat 131 20 Physical characteristics of the targets
table3.dat 108 99626 Master catalog of Andromeda dwarf satellite
galaxies
table4.dat 45 19068 Catalog of long-period variable (LPV) candidates
--------------------------------------------------------------------------------
See also:
II/183 : UBVRI Photometric Standards (Landolt 1992)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/AJ/138/332 : LEDA CMD/tip of the red giant branch (Jacobs+, 2009)
J/MNRAS/411/263 : JHK variable stars in M33 (Javadi+ 2011)
J/A+A/532/A78 : Long-period variables in NGC 147 and NGC 185 (Lorenz+, 2011)
J/ApJ/758/11 : Bayesian distances to M31 satellites (Conn+, 2012)
J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)
J/MNRAS/427/343 : Infrared excesses of Hipparcos stars (McDonald+, 2012)
J/ApJ/779/7 : dSph satellites of M31. I. Var. in And XIX (Cusano+, 2013)
J/MNRAS/435/3206 : Properties of field RR Lyrae variables (Dambis+, 2013)
J/ApJ/789/147 : Star formation histories of LG dwarf galaxies (Weisz+, 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/ApJ/833/167 : PAndAS view of Andromeda satellites. II. (Martin+, 2016)
J/ApJ/850/137 : ISLAndS project. III. Var. stars (Martinez-Vazquez+, 2017)
J/MNRAS/471/770 : Param. and IR excesses of Gaia DR1 stars (McDonald+, 2017)
J/ApJ/894/135 : INT monitoring of Local Group. I. AndI (Saremi+, 2020)
J/MNRAS/512/1091 : NESS II Infrared and Sub-mm results (Scicluna+, 2022)
J/AJ/170/54 : INT monitoring of Local Grp. VII. IC10 phot (Gholami+, 2025)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Galaxy Target galaxy
10 A1 --- r_Galaxy Flag on Galaxy (1)
12- 13 I2 h RAh Hour of right ascension (J2000) (2)
15- 16 I2 min RAm Minute of right ascension (J2000) (2)
18- 21 F4.1 s RAs Second of right ascension (J2000) (2)
23 A1 --- DE- Sign of declination (J2000) (2)
24- 25 I2 deg DEd Degree of declination (J2000) (2)
27- 28 I2 arcmin DEm Arcminute of declination (J2000) (2)
30- 31 I2 arcsec DEs Arcsecond of declination (J2000) (2)
33- 36 F4.2 --- ell [0/0.61] Ellipticity, ε (3)
38- 41 F4.2 --- E_ell [0.02/0.5] Upper uncertainty in ell (3)
43- 46 F4.2 --- e_ell [0/0.5] Lower uncertainty in ell (3)
48- 52 F5.2 [-] [Fe/H] [-2.26/-1.3] Metallicity from
McConnachie (2012, J/AJ/144/4)
54- 57 F4.2 [-] e_[Fe/H] [0.04/0.3]? Uncertainty in [Fe/H]
59- 63 F5.2 arcmin rh [0.4/14.2] Referred half-light radius (3)
65- 68 F4.2 arcmin e_rh [0.1/3.4] Uncertainty in rh (3)
70- 74 F5.2 arcmin rhE [0.5/14.3] Half-light radius obtained from
Exponential fit calculated in this work
(see section 4.2)
76- 79 F4.2 arcmin E_rhE [0.02/0.6] Upper uncertainty in rhE
81- 84 F4.2 arcmin e_rhE [0.02/0.6] Lower uncertainty in rhE
86- 90 F5.2 arcmin rhP [0.49/14.1]? Half-light radius obtained from
Plummer fit calculated in this work
(see section 4.2)
92- 95 F4.2 arcmin E_rhP [0.03/0.54]? Upper uncertainty in rhP
97- 100 F4.2 arcmin e_rhP [0.07/0.54]? Lower uncertainty in rhP
102- 106 F5.2 arcmin rhS [0.49/14.4]? Half-light radius obtained from
Sersic fit calculated in this work
(see section 4.2)
108- 111 F4.2 arcmin E_rhS [0.02/0.6]? Upper uncertainty in rhS
113- 116 F4.2 arcmin e_rhS [0.05/0.6]? Lower uncertainty in rhS
118- 119 I2 --- Ni [4/10] Total number of observations in i-band,
Ei
121 I1 --- NV [1/6] Total number of observations in V-band,
EV
123- 127 I5 --- NTot [2544/11230]? Total number of stellar
population detected in observed field
129- 131 I3 --- NLPV [48/470] Number of confirmed LPV candidates in
observed field based on the criteria
--------------------------------------------------------------------------------
Note (1): Reference as follows:
d = Saremi+ 2020, J/ApJ/894/135
e = Navabi+ 2021ApJ...910..127N 2021ApJ...910..127N
f = Abdollahi+ 2023ApJ...948...63A 2023ApJ...948...63A
Note (2): Coordinates inferred from the NASA/IPAC Extragalactic Database (NED;
https://ned.ipac.caltech.edu/) portal.
Note (3): These half-light radii and ellipticities are referred from
Martin+ 2016, J/ApJ/833/167, except for AndVI which is
from McConnachie (2012, J/AJ/144/4).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Galaxy Target galaxy
10 A1 --- f_Galaxy Flag on Galaxy (1)
12- 16 F5.2 mag magTRGB [20/22.1] TRGB magnitude from this work
18- 21 F4.2 mag e_magTRGB [0.05/0.15] Uncertainty in magTRGB
23- 27 F5.2 mag mu [23.38/25.35] Distance modulus from this work
29- 32 F4.2 mag e_mu [0.05/0.15] Uncertainty in mu
34- 40 F7.2 kpc Dist [473/1177] Distance from this work
42- 46 F5.2 kpc E_Dist [13/55] Upper uncertainty in Dist
48- 52 F5.2 kpc e_Dist [12.9/55] Lower uncertainty in Dist
54- 58 F5.2 mag magTRGBc [20.27/22.2]? TRGB magnitude from
Conn+ 2012, J/ApJ/758/11
60- 63 F4.2 mag e_magTRGBc [0.05/0.6]? Uncertainty in TRGBCmag
65- 69 F5.2 mag b_mu [23.3/25.42] Minimum distance modulus,
µmin
71- 74 F4.2 mag ebmu [0.05/0.5] Uncertainty in b_mu
76 A1 --- fbmu Flag on muMin (3)
78- 84 F7.2 kpc b_Dist [467/1214] Minimum distance
86- 91 F6.2 kpc ebDist [16.9/193] Uncertainty in b_Dist
93- 97 F5.2 mag B_mu [24.13/25.7] Maximum distance modulus,
µmax
99- 102 F4.2 mag eBmu [0.04/0.8]? Uncertainty in B_mu
104 A1 --- rBmu Flag on muMax (3)
106- 112 F7.2 kpc B_Dist [669/1356] Maximum distance
114- 119 F6.2 kpc eBDist [12.4/326]? Uncertainty in B_Dist
121- 125 F5.3 mag Av [0.12/0.54] V-band Galactic extinction (4)
127- 131 F5.3 mag Ai [0.079/0.33] i-band Galactic extinction (4)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
l = Galaxy has been previously studied by the INT group; AndI
(Saremi+ 2021ApJ...923..164S 2021ApJ...923..164S), AndVII (Navabi+ 2021ApJ...910..127N 2021ApJ...910..127N),
and AndIX (Abdollahi+ 2023ApJ...948...63A 2023ApJ...948...63A).
Note (3): Reference as follows:
a = Conn+ (2012ApJ...758...11C 2012ApJ...758...11C ; Cat. J/ApJ/758/11)
b = Martinez-Vazquez+ (2017ApJ...850..137M 2017ApJ...850..137M ; Cat. J/ApJ/850/137)
c = Koenig+ (1993AJ....106.1819K 1993AJ....106.1819K)
d = Dambis+ (2013MNRAS.435.3206D 2013MNRAS.435.3206D ; Cat. J/MNRAS/435/3206)
e = Ferrarese+ (2000ApJ...529..745F 2000ApJ...529..745F)
f = Weisz+ (2014ApJ...789..147W 2014ApJ...789..147W ; Cat. J/ApJ/789/147)
g = Tikhonov+ (1999AstL...25..332T 1999AstL...25..332T)
h = Jacobs+ (2009AJ....138..332J 2009AJ....138..332J ; Cat. J/AJ/138/332)
i = Zucker+ (2004ApJ...612L.121Z 2004ApJ...612L.121Z)
j = Brasseur+ (2011ApJ...729...23B 2011ApJ...729...23B)
k = Zucker+ (2007ApJ...659L..21Z 2007ApJ...659L..21Z)
l = Martin+ (2006MNRAS.371.1983M 2006MNRAS.371.1983M)
m = Collins+ (2010MNRAS.407.2411C 2010MNRAS.407.2411C)
n = Majewski+ (2007ApJ...670L...9M 2007ApJ...670L...9M)
o = Skillman+ (2017ApJ...837..102S 2017ApJ...837..102S)
p = Monelli+ (2016ApJ...819..147M 2016ApJ...819..147M)
q = Irwin+ (2008ApJ...676L..17I 2008ApJ...676L..17I)
r = McConnachie+ (2008ApJ...688.1009M 2008ApJ...688.1009M)
s = Cusano+ (2013ApJ...779....7C 2013ApJ...779....7C ; Cat. J/ApJ/779/7)
t = Martin+ (2009ApJ...705..758M 2009ApJ...705..758M)
u = Chapman+ (2013MNRAS.430...37C 2013MNRAS.430...37C)
Note (4): Cusano et al. (2013, J/ApJ/779/7)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Galaxy Target galaxy
10- 15 I6 --- ID [1/183214] Star identifier within Galaxy
17- 26 F10.6 deg RAdeg Right ascension (J2000)
28- 35 F8.5 deg DEdeg [24.49/47.7] Declination (J2000)
37- 42 F6.3 mag Vmag [9.14/28.42]? Apparent Harris V-band magnitude
44- 49 F6.3 mag e_Vmag [0.002/10.05]? Uncertainty in Vmag
51- 56 F6.3 mag imag [9.58/27.4]? Apparent Sloan i-band magnitude
58- 62 F5.3 mag e_imag [0.002/8]? Uncertainty in imag
64- 69 F6.3 mag Av [0/13.2]? V-band Galactic extinction
71- 76 F6.3 mag Ai [0/14.93]? i-band Galactic extinction
78- 85 F8.3 --- I [-23.65/3751]? I index (1)
87- 92 F6.3 --- J [-7.7/75.7]? Stetson J index (Equation 2)
94- 98 F5.3 --- K [0.38/1]? Kurtosis index K (Equation 4)
100-105 F6.3 --- L [-4.25/45.1]? Final variability index, L
(Equation 5, section 3.4)
107-108 I2 --- N [1/14] Number of observations
--------------------------------------------------------------------------------
Note (1): Index I is the original Welch & Stetson (1993) variability index,
defined as:
I = (1/(n(n-1)))0.5ΣδiδV
where δ is the normalized magnitude deviation from the mean in
each filter. It's the statistic that Stetson (1996PASP..108..851S 1996PASP..108..851S)
later refined into the J index by adding weights and generalizing it
to unpaired observations. It's simply part of the calculation,
following the formula from Welch & Stetson (1993AJ....105.1813W 1993AJ....105.1813W).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Galaxy Target galaxy
10- 15 I6 --- ID [91/182727] Star identifier within Galaxy
17- 30 F14.6 d Date [2457193.69/2458036.4] Julian date
32- 32 A1 --- Filt Filter used
34- 39 F6.3 mag mag [16/28] Apparent magnitude in Filter
41- 45 F5.3 mag e_mag [0.004/10] Uncertainty in mag
--------------------------------------------------------------------------------
History:
From electronic version of the journal
Acknowledgements:
Hedieh Abdollahi [abdollahi.hedieh2013 at gmail dot com]
License: CC-BY-4.0
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 Cat. J/AJ/170/54
Abdollahi et al. Paper VIII. 2026ApJ..1000...69A 2026ApJ..1000...69A This catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Sep-2026