Using dwarf satellite proper motions to determine their origin

G. W. Angus, Antonaldo Diaferio, Pavel Kroupa

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The highly organized distribution of satellite galaxies surrounding the Milky Way is a serious challenge to the concordance cosmological model. Perhaps the only remaining solution, in this framework, is that the dwarf satellite galaxies fall into the Milky Way's potential along one or two filaments, which may or may not plausibly reproduce the observed distribution. Here we test this scenario by making use of the proper motions of the Fornax, Sculptor, Ursa Minor and Carina dwarf spheroidals, and trace their orbits back through several variations of the Milky Way's potential and account for dynamical friction. The key parameters are the proper motions and total masses of the dwarf galaxies. Using a simple model, we find no tenable set of parameters that can allow Fornax to be consistent with filamentary infall, mainly because the 1σ error on its proper motion is relatively small. The other three must walk a tightrope between requiring a small pericentre (less than 20kpc) to lose enough orbital energy to dynamical friction and avoiding being tidally disrupted. We then employed a more realistic model with host halo mass accretion and found that the four dwarf galaxies must have fallen in at least 5Gyr ago. This time-interval is longer than organized distribution is expected to last before being erased by the randomization of the satellite orbits.

Original languageEnglish
Pages (from-to)1401-1409
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume416
Issue number2
DOIs
Publication statusPublished - Sep 2011

Fingerprint

proper motion
dwarf galaxies
friction
galaxies
satellite orbits
halos
filaments
accretion
intervals
orbits
orbitals
energy
distribution
parameter

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Angus, G. W. ; Diaferio, Antonaldo ; Kroupa, Pavel. / Using dwarf satellite proper motions to determine their origin. In: Monthly Notices of the Royal Astronomical Society. 2011 ; Vol. 416, No. 2. pp. 1401-1409.
@article{4aa9a5f0ae6f40dd92e9532096d68d18,
title = "Using dwarf satellite proper motions to determine their origin",
abstract = "The highly organized distribution of satellite galaxies surrounding the Milky Way is a serious challenge to the concordance cosmological model. Perhaps the only remaining solution, in this framework, is that the dwarf satellite galaxies fall into the Milky Way's potential along one or two filaments, which may or may not plausibly reproduce the observed distribution. Here we test this scenario by making use of the proper motions of the Fornax, Sculptor, Ursa Minor and Carina dwarf spheroidals, and trace their orbits back through several variations of the Milky Way's potential and account for dynamical friction. The key parameters are the proper motions and total masses of the dwarf galaxies. Using a simple model, we find no tenable set of parameters that can allow Fornax to be consistent with filamentary infall, mainly because the 1σ error on its proper motion is relatively small. The other three must walk a tightrope between requiring a small pericentre (less than 20kpc) to lose enough orbital energy to dynamical friction and avoiding being tidally disrupted. We then employed a more realistic model with host halo mass accretion and found that the four dwarf galaxies must have fallen in at least 5Gyr ago. This time-interval is longer than organized distribution is expected to last before being erased by the randomization of the satellite orbits.",
author = "Angus, {G. W.} and Antonaldo Diaferio and Pavel Kroupa",
year = "2011",
month = "9",
doi = "10.1111/j.1365-2966.2011.19138.x",
language = "English",
volume = "416",
pages = "1401--1409",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "2",

}

Using dwarf satellite proper motions to determine their origin. / Angus, G. W.; Diaferio, Antonaldo; Kroupa, Pavel.

In: Monthly Notices of the Royal Astronomical Society, Vol. 416, No. 2, 09.2011, p. 1401-1409.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Using dwarf satellite proper motions to determine their origin

AU - Angus, G. W.

AU - Diaferio, Antonaldo

AU - Kroupa, Pavel

PY - 2011/9

Y1 - 2011/9

N2 - The highly organized distribution of satellite galaxies surrounding the Milky Way is a serious challenge to the concordance cosmological model. Perhaps the only remaining solution, in this framework, is that the dwarf satellite galaxies fall into the Milky Way's potential along one or two filaments, which may or may not plausibly reproduce the observed distribution. Here we test this scenario by making use of the proper motions of the Fornax, Sculptor, Ursa Minor and Carina dwarf spheroidals, and trace their orbits back through several variations of the Milky Way's potential and account for dynamical friction. The key parameters are the proper motions and total masses of the dwarf galaxies. Using a simple model, we find no tenable set of parameters that can allow Fornax to be consistent with filamentary infall, mainly because the 1σ error on its proper motion is relatively small. The other three must walk a tightrope between requiring a small pericentre (less than 20kpc) to lose enough orbital energy to dynamical friction and avoiding being tidally disrupted. We then employed a more realistic model with host halo mass accretion and found that the four dwarf galaxies must have fallen in at least 5Gyr ago. This time-interval is longer than organized distribution is expected to last before being erased by the randomization of the satellite orbits.

AB - The highly organized distribution of satellite galaxies surrounding the Milky Way is a serious challenge to the concordance cosmological model. Perhaps the only remaining solution, in this framework, is that the dwarf satellite galaxies fall into the Milky Way's potential along one or two filaments, which may or may not plausibly reproduce the observed distribution. Here we test this scenario by making use of the proper motions of the Fornax, Sculptor, Ursa Minor and Carina dwarf spheroidals, and trace their orbits back through several variations of the Milky Way's potential and account for dynamical friction. The key parameters are the proper motions and total masses of the dwarf galaxies. Using a simple model, we find no tenable set of parameters that can allow Fornax to be consistent with filamentary infall, mainly because the 1σ error on its proper motion is relatively small. The other three must walk a tightrope between requiring a small pericentre (less than 20kpc) to lose enough orbital energy to dynamical friction and avoiding being tidally disrupted. We then employed a more realistic model with host halo mass accretion and found that the four dwarf galaxies must have fallen in at least 5Gyr ago. This time-interval is longer than organized distribution is expected to last before being erased by the randomization of the satellite orbits.

UR - http://www.scopus.com/inward/record.url?scp=80052367105&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80052367105&partnerID=8YFLogxK

U2 - 10.1111/j.1365-2966.2011.19138.x

DO - 10.1111/j.1365-2966.2011.19138.x

M3 - Article

AN - SCOPUS:80052367105

VL - 416

SP - 1401

EP - 1409

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -