The potential role of NGC 205 in generating Andromeda's vast thin corotating plane of satellite galaxies

Journal article

Authors / Editors

Angus, Garry

Research Areas

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Publication Details

Author list: Angus GW, Coppin P, Gentile G, Diaferio A

Publisher: Oxford University Press

Place: OXFORD

Publication year: 2016

Journal: Monthly Notices of the Royal Astronomical Society (0035-8711)

Journal acronym: MON NOT R ASTRON SOC

Volume number: 462

Issue number: 3

Start page: 3221

End page: 3242

Number of pages: 22

ISSN: 0035-8711

eISSN: 1365-2966

Languages: English-Great Britain (EN-GB)

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Abstract

The Andromeda galaxy is observed to have a system of two large dwarf ellipticals and similar to 13 smaller satellite galaxies that are currently corotating in a thin plane, in addition to 2 counter-rotating satellite galaxies. We explored the consistency of those observations with a scenario where the majority of the corotating satellite galaxies originated from a subhalo group, where NGC 205 was the host and the satellite galaxies occupied dark matter sub-subhaloes. We ran N-body simulations of a close encounter between NGC 205 and M31. In the simulations, NGC 205 was surrounded by massless particles to statistically sample the distribution of the sub-subhaloes expected in a subhalo that has a mass similar to NGC 205. We made Monte Carlo samplings and found that, using a set of reference parameters, the probability of producing a thinner distribution of sub-subhaloes than the observed NGC 205 + 15 smaller satellites (thus including the two counter-rotators, but excluding M32) increased from < 10(-8) for the initial distribution to similar to 10(-2) at pericentre. The probability of the simulated sub-subhaloes occupying the locations of the observed corotating satellites in the line-of-sight velocity versus projected on-sky distance plane is at most 2 x 10(-3) for 11 out of 13 satellites. Increasing the mass of M31 and the extent of the initial distribution of sub-subhaloes gives a maximum probability of 4 x 10(-3) for all 13 corotating satellites, but the probability of producing the thinness would drop to similar to 10(-3).

Keywords

Dark matter, galaxies: kinematics and dynamics, Local Group, methods: numerical

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