2025A&A...703A...1M

Query : 2025A&A...703A...1M

2025A&A...703A...1M - Astronomy and Astrophysics, volume 703A1-15 (2025/11-1)

The long-term stability of the Vast Polar Structure and its connection to a possible previous passage of the LMC.

MARTINEZ-GARCIA A.M. and DEL PINO A.

Abstract (from CDS):

Context. The Vast Polar Structure (VPOS) is a thin planar arrangement of co-orbiting dwarf galaxies that is nearly perpendicular to the Milky Way (MW) disc. Its origin and long-term evolution remain open questions.
Aims. We investigate the persistence and stability of the VPOS over time.
Methods. We identified VPOS member galaxies and integrated their orbits over the past 5 Gyr using accurate phase-space data and time-evolving gravitational potentials that accounted for the mutual interaction between the MW and the Large Magellanic Cloud (LMC).
Results. We identified 15 galaxies as members of the VPOS, including nine MW and six LMC satellites. The VPOS has remained a stable structure and maintained a roughly constant thickness (∼15 kpc), flattening (c/a ∼ 0.2) and orientation over time. While the LMC exerts a strong gravitational influence on the MW satellites, its impact on the VPOS is limited and only leads to mild perturbations. The structural properties of the VPOS remain almost unchanged, regardless of whether LMC satellites were included in the analysis. This indicates a smooth dynamical integration with the rest of VPOS members upon entering the virial radius of the MW. This minimal dynamical impact on the VPOS results from the remarkable alignment between the LMC orbit and the orientation of the plane.
Conclusions. The VPOS is not a transient alignment, but a long-lived planar structure in the MW system that has persisted for at least the last 5 Gyr. Notably, the VPOS predates the LMC infall, which rules out formation scenarios that are tied to its recent approach to the MW. Our findings suggest a strong connection between the VPOS and the LMC. This is consistent with a scenario in which the LMC is on its second pericentre and the VPOS originated primarily from satellites that were stripped during the first passage.

Abstract Copyright: © The Authors 2025

Journal keyword(s): galaxies: dwarf - galaxies: kinematics and dynamics - Local Group - Magellanic Clouds

Simbad objects: 72

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Number of rows : 72
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 Magellanic Stream HVC 00 32 -30.0           ~ 1079 1
3 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
4 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 3588 2
5 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
6 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
7 NAME Phoenix Dwarf Galaxy Sy1 01 51 06.3 -44 26 41   13.48 13.2 12.69   ~ 575 2
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 Hydrus I G 02 29 33.4 -79 18 32           ~ 80 0
12 MCG-06-07-001 G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1894 1
13 NAME Hor I G 02 55 31.7 -54 07 08           ~ 169 0
14 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7988 0
15 NAME Horologium II G 03 16 32.1 -50 01 05           ~ 76 0
16 NAME Reticulum II G 03 35 42.1 -54 02 57           ~ 375 0
17 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
18 NAME Reticulum III G 03 45.4 -60 27           ~ 67 0
19 NAME Eridanus IV G 05 05 45 -09 30.9     14.72     ~ 15 0
20 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 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 NGC 2750 GiP 09 05 47.893 +25 26 14.51   12.7       ~ 121 0
27 NAME Leo T G 09 34 53.4 +17 03 05     15.1     ~ 434 0
28 NAME Antlia II Dwarf Galaxy G 09 35 32.8 -36 46 02           ~ 109 0
29 M 81 Sy2 09 55 33.1726556496 +69 03 55.062505368   7.89 6.94     ~ 4725 3
30 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 517 1
31 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1284 1
32 NAME Sextans dSph LSB 10 13 02.9 -01 36 53   12 10.4     ~ 921 0
33 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 355 1
34 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 345 0
35 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 0
36 NAME Leo VI G 11 24 18 +24 52.4           ~ 4 0
37 NAME Leo V LSB 11 31 09.60 +02 13 12.0     16.0     ~ 234 0
38 NAME Leo IV LSB 11 32 57.0 -00 32 00     15.1     ~ 419 1
39 NAME Crater Cluster GlC 11 36 16.20 -10 52 38.8           ~ 117 1
40 NAME Crater II Dwarf Galaxy G 11 49 14 -18 24.8           ~ 176 0
41 NAME Hydra II G 12 21 42.1 -31 59 07           ~ 118 0
42 NAME Coma Dwarf Galaxy G 12 26 59.0 +23 54 15     14.1     ~ 482 1
43 NGC 4490 GiG 12 30 34.5 +41 38 26 10.03 10.22 9.79     ~ 616 3
44 NAME NGP reg 12 51 26.275 +27 07 41.70           ~ 1274 0
45 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
46 NAME Centaurus A BLL 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4774 3
47 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 352 1
48 NAME Bootes III G 13 57 07.4 +26 46 30     12.6     ~ 115 1
49 NAME Bootes II G 13 58 00.0 +12 51 00     15.4     ~ 269 0
50 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
51 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 3138 2
52 NAME Bootes V Dwarf Galaxy G 14 15 38 +32 54.8     16.84     ~ 10 0
53 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
54 NAME Draco II Gl? 15 52 47.6 +64 33 55           ~ 138 0
55 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
56 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
57 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
58 NAME SDG G 18 55 19.0 -30 32 43   4.5 3.6     ~ 2438 2
59 NGC 6822 G 19 44 56.199 -14 47 51.29   18 8.1     ~ 1661 0
60 NAME Sagittarius II Gl? 19 52 40.5 -22 04 05           ~ 97 0
61 NAME Pegasus IV G 21 54 09 +26 37.2           ~ 15 0
62 NAME Gru II G 22 04.1 -46 26           ~ 110 0
63 NAME Pegasus III LSB 22 24 22.6 +05 25 12           ~ 69 0
64 NAME Aquarius 2 G 22 33 55.5 -09 19 39           ~ 66 0
65 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
66 NAME Grus I G 22 56 42.4 -50 09 48           ~ 126 0
67 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 283 0
68 NAME Tuc V G 23 37.4 -63 16           ~ 84 0
69 NAME Phe II G 23 39 59.4 -54 24 22           ~ 107 0
70 NAME Aquarius III G 23 48 52 -03 29.3           ~ 6 0
71 NAME Tuc III G 23 56.6 -59 36           ~ 229 0
72 NAME Local Group GrG ~ ~           ~ 9325 0

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