2024AJ....167...57T

Query : 2024AJ....167...57T

2024AJ....167...57T - Astron. J., 167, 57 (2024/February-0)

Extended Stellar Populations in Ultrafaint Dwarf Galaxies.

TAU E.A., VIVAS A.K. and MARTINEZ-VAZQUEZ C.E.

Abstract (from CDS):

The possible existence of stellar halos in low-mass galaxies is being intensely discussed nowadays after some recent discoveries of stars located in the outskirts of dwarf galaxies of the Local Group. RR Lyrae stars can be used to identify the extent of these structures, taking advantage of the minimization of foreground contamination they provide. In this work we use RR Lyrae stars obtained from Gaia DR3, the Dark Energy Survey, the Zwicky Transient Facility, and Pan-STARRS1 to explore the outskirts of 45 ultrafaint dwarf galaxies. We associate the stars with a host galaxy based on their angular separations, magnitudes, and proper motions. We find a total of 120 RR Lyrae stars that belong to 21 different galaxies in our sample. We report seven new RR Lyrae stars in six ultrafaint dwarf galaxies (Hydrus I, Ursa Major I, Ursa Major II, Grus II, Eridanus II, and Tucana II). We found a large number of new possible members in Bootes I and Bootes III as well, but some of them may actually belong to the nearby Sagittarius stream. Adding to our list of 120 RR Lyrae stars the observations of other ultrafaint dwarf galaxies that were beyond the reach of our search, we find that at least 10 of these galaxies have RR Lyrae stars located at distances greater than four times their respective half-light radius, which implies that at least 33% of the 30 ultrafaint dwarfs with a population of RR Lyrae stars have extended stellar populations.

Abstract Copyright: © 2024. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): RR Lyrae variable stars - Dwarf galaxies - Galaxy stellar halos - Local Group

Simbad objects: 58

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Number of rows : 58
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME Tuc IV G 00 02.9 -60 51           ~ 90 0
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
3 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
4 NAME Cetus II G 01 17.9 -17 25           ~ 56 0
5 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 6226 1
6 DELVE 2 Cl* 01 55 05 -68 15.2     17.16     ~ 20 0
7 NAME Cetus III Dwarf Galaxy LSB 02 05 19.40 -04 16 12.0           ~ 32 0
8 NAME Tri II G 02 13 17.40 +36 10 42.4           ~ 164 0
9 NAME Segue 2 G 02 19 16.0 +20 10 31     15.2     ~ 299 0
10 NAME Sagittarius Stream St* 02 22 +00.0           ~ 1001 0
11 NAME Eri III G 02 22 45.480 -52 17 04.92           ~ 79 0
12 NAME Hydrus I G 02 29 33.4 -79 18 32           ~ 80 0
13 MCG-06-07-001 G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1894 1
14 NAME Hor I G 02 55 31.7 -54 07 08           ~ 169 0
15 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7988 0
16 NAME Horologium II G 03 16 32.1 -50 01 05           ~ 76 0
17 NAME Reticulum II G 03 35 42.1 -54 02 57           ~ 375 0
18 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
19 NAME Reticulum III G 03 45.4 -60 27           ~ 67 0
20 NAME Eridanus IV G 05 05 45 -09 30.9     14.72     ~ 15 0
21 NAME Col I G 05 31.4 -28 02           ~ 60 0
22 ESO 206-20A G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1190 0
23 NAME Carina II Dwarf Galaxy G 07 36 25.6 -57 59 57           ~ 86 0
24 NAME Car III Dwarf Galaxy G 07 38 31.2 -57 53 59           ~ 81 0
25 NAME UMa II Galaxy G 08 51 30.0 +63 07 48     13.3     ~ 410 0
26 NAME Leo T G 09 34 53.4 +17 03 05     15.1     ~ 434 0
27 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 517 1
28 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 355 1
29 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 345 0
30 NAME Leo V LSB 11 31 09.60 +02 13 12.0     16.0     ~ 234 0
31 NAME Leo IV LSB 11 32 57.0 -00 32 00     15.1     ~ 419 1
32 NAME Vir I Dwarf Galaxy LSB 12 00 09.6 -00 40 48           ~ 40 0
33 NAME Hydra II G 12 21 42.1 -31 59 07           ~ 118 0
34 NAME Coma Dwarf Galaxy G 12 26 59.0 +23 54 15     14.1     ~ 482 1
35 NAME Centaurus I G 12 38 20 -40 54.1     14.78     ~ 29 0
36 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
37 NAME Styx Stream St* 13 56 24.0 +26 48 00           ~ 30 0
38 NAME Bootes III G 13 57 07.4 +26 46 30     12.6     ~ 115 1
39 NAME Bootes II G 13 58 00.0 +12 51 00     15.4     ~ 269 0
40 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
41 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
42 NAME Draco II Gl? 15 52 47.6 +64 33 55           ~ 138 0
43 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
44 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
45 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
46 NAME Orphan Stream St* 19 09 -23.           ~ 281 0
47 NAME Sagittarius II Gl? 19 52 40.5 -22 04 05           ~ 97 0
48 NAME Pegasus IV G 21 54 09 +26 37.2           ~ 15 0
49 NAME Gru II G 22 04.1 -46 26           ~ 110 0
50 NAME Pegasus III LSB 22 24 22.6 +05 25 12           ~ 69 0
51 NAME Aquarius 2 G 22 33 55.5 -09 19 39           ~ 66 0
52 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
53 NAME Grus I G 22 56 42.4 -50 09 48           ~ 126 0
54 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 283 0
55 NAME Tuc V G 23 37.4 -63 16           ~ 84 0
56 NAME Phe II G 23 39 59.4 -54 24 22           ~ 107 0
57 NAME Tuc III G 23 56.6 -59 36           ~ 229 0
58 NAME Local Group GrG ~ ~           ~ 9325 0

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