2024A&A...681A..73T

Query : 2024A&A...681A..73T

2024A&A...681A..73T - Astronomy and Astrophysics, volume 681A73 (2024/1-1)

A portrait of the vast polar structure as a young phenomenon: Hints from its member satellites.

TAIBI S., PAWLOWSKI M.S., KHOPERSKOV S., STEINMETZ M. and LIBESKIND N.I.

Abstract (from CDS):

Context. It has been observed that several Milky Way (MW) satellite dwarf galaxies are distributed along a coherent planar distribution known as the vast polar structure (VPOS).
Aims. Here we investigate whether MW satellites located on the VPOS have different physical and orbital properties from those not associated with it.
Methods. Using the proper motion measurements of the MW satellites from the Gaia mission and literature values for their observational parameters, we first discriminate between systems that may or may not be associated with the VPOS, and then compare their chemical and dynamical properties.
Results. Comparing the luminosity distributions of the on-plane and off-plane samples, we find an excess of bright satellites observed on the VPOS. Despite this luminosity gap, we do not observe a significant preference for on-plane or off-plane systems to follow different scaling relations. The on-plane systems also show a striking pattern in their radial velocities and orbital phases: almost all co-orbiting satellites are approaching their pericentre, while both counter-orbiting ones are leaving their last pericentre. This is in contrast to the more random distribution of the off-plane sample. The on-plane systems also tend to have the lowest orbital energies for a given value of angular momentum. These results are robust to the assumed MW potential, even in the case of a potential perturbed by the arrival of a massive Large Magellanic Cloud. Considering them a significant property of the VPOS, we explore several scenarios, all related to the late accretion of satellite systems, which interpret the VPOS as a young structure.
Conclusions. From the results obtained, we hypothesise that the VPOS formed as a result of the accretion of a group of dwarf galaxies. More accurate proper motions and dedicated studies in the context of cosmological simulations are needed to confirm this scenario.

Abstract Copyright: © The Authors 2024

Journal keyword(s): galaxies: dwarf - Local Group - galaxies: kinematics and dynamics - galaxies: luminosity function - mass function - galaxies: abundances - galaxies: statistics

Simbad objects: 57

goto Full paper

goto View the references in ADS

Number of rows : 57
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 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
3 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 12317 1
4 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
5 NAME Tri II G 02 13 17.40 +36 10 42.4           ~ 164 0
6 NAME Segue 2 G 02 19 16.0 +20 10 31     15.2     ~ 299 0
7 NAME Sagittarius Stream St* 02 22 +00.0           ~ 1001 0
8 NAME Hydrus I G 02 29 33.4 -79 18 32           ~ 80 0
9 V* MW And EB* 02 31 28.9714789824 +39 41 18.999802176   15.23 14.21 14.10   ~ 17 0
10 MCG-06-07-001 G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1894 1
11 NAME Hor I G 02 55 31.7 -54 07 08           ~ 169 0
12 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 7988 0
13 NAME Horologium II G 03 16 32.1 -50 01 05           ~ 76 0
14 NAME Reticulum II G 03 35 42.1 -54 02 57           ~ 375 0
15 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
16 NAME Reticulum III G 03 45.4 -60 27           ~ 67 0
17 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
18 NAME Col I G 05 31.4 -28 02           ~ 60 0
19 ESO 206-20A G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1190 0
20 NAME Carina II Dwarf Galaxy G 07 36 25.6 -57 59 57           ~ 86 0
21 NAME Car III Dwarf Galaxy G 07 38 31.2 -57 53 59           ~ 81 0
22 NAME UMa II Galaxy G 08 51 30.0 +63 07 48     13.3     ~ 410 0
23 NAME Antlia II Dwarf Galaxy G 09 35 32.8 -36 46 02           ~ 109 0
24 NAME Segue 1 G 10 07 03.2 +16 04 25     15.3     ~ 517 1
25 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1284 1
26 NAME Sextans dSph LSB 10 13 02.9 -01 36 53   12 10.4     ~ 921 0
27 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 355 1
28 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 345 0
29 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 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 Crater Cluster GlC 11 36 16.20 -10 52 38.8           ~ 117 1
33 NAME Crater II Dwarf Galaxy G 11 49 14 -18 24.8           ~ 176 0
34 NAME Hydra II G 12 21 42.1 -31 59 07           ~ 118 0
35 NAME Coma Dwarf Galaxy G 12 26 59.0 +23 54 15     14.1     ~ 482 1
36 NAME CVn II dSph G 12 57 09.6 +34 19 12     16.1     ~ 287 2
37 NAME Centaurus A BLL 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4774 3
38 NAME CVn I dSph G 13 28 03.5 +33 33 21     13.1     ~ 352 1
39 NAME Bootes III G 13 57 07.4 +26 46 30     12.6     ~ 115 1
40 NAME Bootes II G 13 58 00.0 +12 51 00     15.4     ~ 269 0
41 NAME Bootes Dwarf Spheroidal Galaxy G 14 00 00.0 +14 30 00     12.8     ~ 491 0
42 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
43 NAME Draco II Gl? 15 52 47.6 +64 33 55           ~ 138 0
44 NAME Hercules Dwarf Galaxy G 16 31 02.0 +12 47 30     14.0     ~ 379 1
45 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
46 NAME Sagittarius II Gl? 19 52 40.5 -22 04 05           ~ 97 0
47 NAME Gru II G 22 04.1 -46 26           ~ 110 0
48 NAME Pegasus III LSB 22 24 22.6 +05 25 12           ~ 69 0
49 NAME Aquarius 2 G 22 33 55.5 -09 19 39           ~ 66 0
50 NAME Tuc II G 22 51 55.1 -58 34 08           ~ 192 0
51 NAME Grus I G 22 56 42.4 -50 09 48           ~ 126 0
52 NAME Pisces II G 22 58 31.0 +05 57 09     16.3     ~ 283 0
53 NAME Tuc V G 23 37.4 -63 16           ~ 84 0
54 NAME Phe II G 23 39 59.4 -54 24 22           ~ 107 0
55 NAME Tuc III G 23 56.6 -59 36           ~ 229 0
56 NAME Gaia Enceladus-Sausage St* ~ ~           ~ 860 0
57 NAME Local Group GrG ~ ~           ~ 9325 0

To bookmark this query, right click on this link: simbad:objects in 2024A&A...681A..73T and select 'bookmark this link' or equivalent in the popup menu