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Title: Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe

Abstract

The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
900234
Report Number(s):
SLAC-PUB-12362
astro-ph/0702495; TRN: US200711%%315
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nature 445:738-740,2007; Journal Volume: 445
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXIES; HEATING; MILKY WAY; NONLUMINOUS MATTER; ORIGIN; SATELLITES; UNIVERSE; Astrophysics,ASTRO

Citation Formats

Mayer, Lucio, /Zurich, ETH /Zurich U., Kazantzidis, Stelios, /KIPAC, Menlo Park /KICP, Chicago, Mastropietro, Chiara, /Munich U. Observ., Wadsley, James, and /McMaster U. Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe. United States: N. p., 2007. Web. doi:10.1038/nature05552.
Mayer, Lucio, /Zurich, ETH /Zurich U., Kazantzidis, Stelios, /KIPAC, Menlo Park /KICP, Chicago, Mastropietro, Chiara, /Munich U. Observ., Wadsley, James, & /McMaster U. Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe. United States. doi:10.1038/nature05552.
Mayer, Lucio, /Zurich, ETH /Zurich U., Kazantzidis, Stelios, /KIPAC, Menlo Park /KICP, Chicago, Mastropietro, Chiara, /Munich U. Observ., Wadsley, James, and /McMaster U. Wed . "Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe". United States. doi:10.1038/nature05552. https://www.osti.gov/servlets/purl/900234.
@article{osti_900234,
title = {Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe},
author = {Mayer, Lucio and /Zurich, ETH /Zurich U. and Kazantzidis, Stelios and /KIPAC, Menlo Park /KICP, Chicago and Mastropietro, Chiara and /Munich U. Observ. and Wadsley, James and /McMaster U.},
abstractNote = {The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.},
doi = {10.1038/nature05552},
journal = {Nature 445:738-740,2007},
number = ,
volume = 445,
place = {United States},
year = {Wed Feb 28 00:00:00 EST 2007},
month = {Wed Feb 28 00:00:00 EST 2007}
}
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