2024MNRAS.527.2403G

Query : 2024MNRAS.527.2403G

2024MNRAS.527.2403G - Mon. Not. R. Astron. Soc., 527, 2403-2412 (2024/January-2)

EDGE: The direct link between mass growth history and the extended stellar haloes of the faintest dwarf galaxies.

GOATER A., READ J.I., NOEL N.E.D., ORKNEY M.D.A., KIM S.Y., REY M.P., ANDERSSON E.P., AGERTZ O., PONTZEN A., VIELIUTE R., KATARIA D. and JENEWAY K.

Abstract (from CDS):

Ultra-faint dwarf galaxies (UFDs) are commonly found in close proximity to the Milky Way and other massive spiral galaxies. As such, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal forces. In this paper, we study the projected stellar ellipticities and faint stellar outskirts of tidally isolated ultra-faints drawn from the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) cosmological simulation suite. Despite their tidal isolation, our simulated dwarfs exhibit a wide range of projected ellipticities (0.03 < ε < 0.85), with many possessing anisotropic extended stellar haloes that mimic tidal tails, but owe instead to late-time accretion of lower mass companions. Furthermore, we find a strong causal relationship between ellipticity and formation time of a UFD, which is robust to a wide variation in the feedback model. We show that the distribution of projected ellipticities in our suite of simulated EDGE dwarfs matches well with a sample of 19 Local Group dwarf galaxies and a sample of 11 isolated dwarf galaxies. Given ellipticity in EDGE arises from an ex-situ accretion origin, the agreement in shape indicates the ellipticities of some observed dwarfs may also originate from a non-tidal scenario. The orbital parameters of these observed dwarfs further support that they are not currently tidally disrupting. If the baryonic content in these galaxies is still tidally intact, then the same may be true for their dark matter content, making these galaxies in our Local Group pristine laboratories for testing dark matter and galaxy formation models.

Abstract Copyright: © 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): galaxies: dwarf - galaxies: formation - galaxies: stellar content - galaxies: structure

Simbad objects: 35

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Number of rows : 35
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 Cetus Dwarf Galaxy G 00 26 10.8 -11 03 14     13.2     ~ 257 0
2 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
3 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
4 M 33 GiG 01 33 50.8965749232 +30 39 36.630403128 6.17 6.27 5.72     ~ 6226 1
5 NAME Phoenix Dwarf Galaxy Sy1 01 51 06.3 -44 26 41   13.48 13.2 12.69   ~ 575 2
6 NAME Hydrus I G 02 29 33.4 -79 18 32           ~ 80 0
7 NAME Reticulum II G 03 35 42.1 -54 02 57           ~ 375 0
8 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
9 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
10 ESO 206-20A G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1190 0
11 NAME Leo K Dwarf Galaxy LSB 09 24 06.1 +16 30 38           ~ 8 0
12 NAME Leo T G 09 34 53.4 +17 03 05     15.1     ~ 434 0
13 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1284 1
14 NAME Sextans dSph LSB 10 13 02.9 -01 36 53   12 10.4     ~ 921 0
15 NAME Leo P BiC 10 21 45.123 +18 05 16.89           ~ 268 0
16 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 355 1
17 NAME Leo M Dwarf Galaxy LSB 11 05 21.43 +25 20 43.0           ~ 8 0
18 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 0
19 NAME Leo V LSB 11 31 09.60 +02 13 12.0     16.0     ~ 234 0
20 NAME Leo IV LSB 11 32 57.0 -00 32 00     15.1     ~ 419 1
21 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
22 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 352 1
23 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
24 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
25 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
26 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
27 NAME Pavo Dwarf Galaxy G 19 54 59.98 -61 04 20.5           ~ 9 0
28 NAME Pegasus III LSB 22 24 22.6 +05 25 12           ~ 69 0
29 NAME Tuc Galaxy G 22 41 49.6 -64 25 10   15.7 15.2     ~ 324 0
30 NAME Tucana B LSB 22 47 00.50 -58 24 27.0           ~ 22 0
31 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
32 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 283 0
33 Z 431-72 G 23 28 35.2 +14 44 35 13.85 13.16 12.52     ~ 499 1
34 NAME Pegasus W Dwarf Galaxy G 23 53 14.99560 +22 06 07.0928           ~ 8 0
35 NAME Local Group GrG ~ ~           ~ 9325 0

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