2021ApJ...922...93H

Query : 2021ApJ...922...93H

2021ApJ...922...93H - Astrophys. J., 922, 93-93 (2021/December-1)

Gaia EDR3 proper motions of Milky Way dwarfs. II. Velocities, total energy, and angular momentum.

HAMMER F., WANG J., PAWLOWSKI M.S., YANG Y., BONIFACIO P., LI H., BABUSIAUX C. and ARENOU F.

Abstract (from CDS):

Here we show that precise Gaia EDR3 proper motions have provided robust estimates of 3D velocities, angular momentum, and total energy for 40 Milky Way dwarfs. The results are statistically robust and are independent of the Milky Way mass profile. Dwarfs do not behave like long-lived satellites of the Milky Way because of their excessively large velocities, angular momenta, and total energies. Comparing them to other MW halo populations, we find that many are at first passage, <=2 Gyr ago, i.e., more recent than the passage of Sagittarius, ∼4-5 Gyr ago. We suggest that this is in agreement with the stellar populations of all dwarfs, for which we find that a small fraction of young stars cannot be excluded. We also find that dwarf radial velocities contribute too little to their kinetic energy when compared to satellite systems with motions only regulated by gravity, and some other mechanism must be at work such as ram pressure. The latter may have preferentially reduced radial velocities when dwarf progenitors entered the halo until they lost their gas. It could also explain why most dwarfs lie near their pericenter. We also discover a novel large-scale structure perpendicular to the Milky Way disk, which is made by 20% of dwarfs orbiting or counter-orbiting with the Sagittarius dwarf.

Abstract Copyright: © 2021. The American Astronomical Society. All rights reserved.

Journal keyword(s): Local Group - Magellanic Clouds - Milky Way Galaxy - Galaxy rotation curves - Dark matter - Observational cosmology - Dwarf spheroidal galaxies

Simbad objects: 49

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Number of rows : 49
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 Magellanic Stream HVC 00 32 -30.0           ~ 1079 1
2 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
3 NAME M31 Group GrG 00 47 28.6 +40 17 23           ~ 65 0
4 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
5 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
6 NAME Tri II G 02 13 17.40 +36 10 42.4           ~ 164 0
7 NAME Segue 2 G 02 19 16.0 +20 10 31     15.2     ~ 299 0
8 NAME Sagittarius Stream St* 02 22 +00.0           ~ 1001 0
9 MCG-06-07-001 G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1894 1
10 NAME Hor I G 02 55 31.7 -54 07 08           ~ 169 0
11 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7988 0
12 NAME Horologium II G 03 16 32.1 -50 01 05           ~ 76 0
13 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
14 NAME Reticulum III G 03 45.4 -60 27           ~ 67 0
15 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
16 NAME Col I G 05 31.4 -28 02           ~ 60 0
17 RMC 136 Cl* 05 38 42.396 -69 06 03.36   5.81 5.40     ~ 2236 2
18 ESO 206-20A G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1190 0
19 NAME Carina II Dwarf Galaxy G 07 36 25.6 -57 59 57           ~ 86 0
20 NAME Antlia II Dwarf Galaxy G 09 35 32.8 -36 46 02           ~ 109 0
21 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 517 1
22 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1284 1
23 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 345 0
24 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 0
25 NAME Leo V LSB 11 31 09.60 +02 13 12.0     16.0     ~ 234 0
26 NAME Leo IV LSB 11 32 57.0 -00 32 00     15.1     ~ 419 1
27 NAME Crater II Dwarf Galaxy G 11 49 14 -18 24.8           ~ 176 0
28 NAME Hydra II G 12 21 42.1 -31 59 07           ~ 118 0
29 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
30 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 352 1
31 NAME Bootes II G 13 58 00.0 +12 51 00     15.4     ~ 269 0
32 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
33 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
34 NAME Draco II Gl? 15 52 47.6 +64 33 55           ~ 138 0
35 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
36 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
37 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
38 NAME SDG G 18 55 19.0 -30 32 43   4.5 3.6     ~ 2438 2
39 NAME Sagittarius II Gl? 19 52 40.5 -22 04 05           ~ 97 0
40 NAME Gru II G 22 04.1 -46 26           ~ 110 0
41 NAME Aquarius 2 G 22 33 55.5 -09 19 39           ~ 66 0
42 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
43 NAME Grus I G 22 56 42.4 -50 09 48           ~ 126 0
44 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 283 0
45 NAME Tuc V G 23 37.4 -63 16           ~ 84 0
46 NAME Phe II G 23 39 59.4 -54 24 22           ~ 107 0
47 NAME Tuc III G 23 56.6 -59 36           ~ 229 0
48 NAME Gaia Enceladus-Sausage St* ~ ~           ~ 860 0
49 NAME Local Group GrG ~ ~           ~ 9325 0

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