2009A&A...499..385P


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.23CET09:48:53

2009A&A...499..385P - Astronomy and Astrophysics, volume 499, 385-394 (2009/5-4)

Tidal effects on the spatial structure of the Local Group.

PASETTO S. and CHIOSI C.

Abstract (from CDS):

The spatial distribution of galaxies in the Local Group (LG) is the footprint of its formation mechanism and the gravitational interactions among its members and the external massive galaxies or galaxy groups. Using a 3D-geometrical description of the spatial distribution of all the members of the LG (not only the satellites of the MW and M31) based on present-day data of positions and distances, we found in our previous study that all galaxies (MW, M31, their satellites, and even the most distant objects) are confined within a slab of about 200 kpc thickness. Examining how external galaxies or groups would gravitationally affect (and eventually alter) the planar structure (and its temporal evolution) of the LG, they found that the external force field acts parallel to the plane determined by geometry and studied this with the Least Action Principle. In this paper, we thoroughly investigated the role played by the tidal forces exerted by external galaxies or galaxy groups on the LG galaxies (the most distant dwarfs in particular) in shaping their large-scale distribution. We studied in particular an idea based on the well-known effect of tidal interactions, according to which a system of mass-points can undergo not only tidal stripping but also tidal compression and thus become flatter. Excluding the dwarf galaxies tightly bound to the MW and M31, the same tidal forces can account for the planar distribution of the remaining dwarf galaxies. We analytically recover our previous results and prove that a planar distribution of the LG dwarf galaxies is compatible with the external force field. We also highlight the physical cause of this result.

Abstract Copyright:

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

Simbad objects: 10

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Number of rows : 10

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10708 1
2 NAME Scl Group GrG 01 00 06 -33 44.2           ~ 456 0
3 NAME IC 342 Group GrG 03 48 42 +68 00.8           ~ 97 1
4 NAME M 81-82 Group GrG 09 55 +69.1           ~ 624 0
5 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 3923 5
6 NAME Cen A Group GrG 13 20 33.9 -44 58 51           ~ 225 0
7 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 3937 3
8 M 83 SBG 13 37 00.919 -29 51 56.74 8.85 8.11 7.52 7.21   ~ 2187 2
9 NAME NGC 5236 Group GrG 13 37 06 -29 51.9           ~ 55 0
10 NAME Local Group GrG ~ ~           ~ 6802 0

    Equat.    Gal    SGal    Ecl

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2020.02.23-09:48:53

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