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Faint stars in the Ursa Minor dwarf spheroidal galaxy: implications for the low-mass stellar initial mass function at high redshift

Wyse, RFG; Gilmore, G; Houdashelt, ML; Feltzing, Sofia LU ; Hebb, L; Gallagher, JS and Smecker-Hane, TA (2002) In New Astronomy 7(7). p.395-433
Abstract
The stellar initial mass function at high redshift is an important defining property of the first stellar systems to form and may also play a role in various dark matter problems. We here determine the faint stellar luminosity function in an apparently dark-matter-dominated external galaxy in which the stars formed at high redshift. The Ursa Minor dwarf spheroidal galaxy is a system with a particularly simple stellar population-all of the stars being old and metal-poor-similar to that of a classical halo globular cluster. A direct comparison of the faint luminosity functions of the UMi dSph and of similar metallicity, old globular clusters is equivalent to a comparison of the initial mass functions and is presented here, based on deep HST... (More)
The stellar initial mass function at high redshift is an important defining property of the first stellar systems to form and may also play a role in various dark matter problems. We here determine the faint stellar luminosity function in an apparently dark-matter-dominated external galaxy in which the stars formed at high redshift. The Ursa Minor dwarf spheroidal galaxy is a system with a particularly simple stellar population-all of the stars being old and metal-poor-similar to that of a classical halo globular cluster. A direct comparison of the faint luminosity functions of the UMi dSph and of similar metallicity, old globular clusters is equivalent to a comparison of the initial mass functions and is presented here, based on deep HST WFPC2 and STIS imaging data. We find that these luminosity functions are indistinguishable, down to a luminosity corresponding to similar to0.3 M-.. Our results show that the low-mass stellar IMF for stars that formed at very high redshift is apparently invariant across environments as diverse as those of an extremely low-surface-brightness, dark-matter-dominated dwarf galaxy and a dark-matter-free, high-density globular cluster within the Milky Way. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
individual : Ursa Minor, mass function, stars : luminosity function, dark matter, galaxies : stellar content, kinematics and dynamics, galaxies :
in
New Astronomy
volume
7
issue
7
pages
395 - 433
publisher
Elsevier
external identifiers
  • wos:000178496100003
  • scopus:31244436674
ISSN
1384-1092
DOI
10.1016/S1384-1076(02)00156-2
language
English
LU publication?
yes
id
08c7f35d-b070-4e9e-9b0b-a81c237c42a2 (old id 325968)
alternative location
http://arxiv.org/abs/astro-ph/0206144
date added to LUP
2007-11-19 12:36:31
date last changed
2017-12-10 03:43:48
@article{08c7f35d-b070-4e9e-9b0b-a81c237c42a2,
  abstract     = {The stellar initial mass function at high redshift is an important defining property of the first stellar systems to form and may also play a role in various dark matter problems. We here determine the faint stellar luminosity function in an apparently dark-matter-dominated external galaxy in which the stars formed at high redshift. The Ursa Minor dwarf spheroidal galaxy is a system with a particularly simple stellar population-all of the stars being old and metal-poor-similar to that of a classical halo globular cluster. A direct comparison of the faint luminosity functions of the UMi dSph and of similar metallicity, old globular clusters is equivalent to a comparison of the initial mass functions and is presented here, based on deep HST WFPC2 and STIS imaging data. We find that these luminosity functions are indistinguishable, down to a luminosity corresponding to similar to0.3 M-.. Our results show that the low-mass stellar IMF for stars that formed at very high redshift is apparently invariant across environments as diverse as those of an extremely low-surface-brightness, dark-matter-dominated dwarf galaxy and a dark-matter-free, high-density globular cluster within the Milky Way.},
  author       = {Wyse, RFG and Gilmore, G and Houdashelt, ML and Feltzing, Sofia and Hebb, L and Gallagher, JS and Smecker-Hane, TA},
  issn         = {1384-1092},
  keyword      = {individual : Ursa Minor,mass function,stars : luminosity function,dark matter,galaxies : stellar content,kinematics and dynamics,galaxies :},
  language     = {eng},
  number       = {7},
  pages        = {395--433},
  publisher    = {Elsevier},
  series       = {New Astronomy},
  title        = {Faint stars in the Ursa Minor dwarf spheroidal galaxy: implications for the low-mass stellar initial mass function at high redshift},
  url          = {http://dx.doi.org/10.1016/S1384-1076(02)00156-2},
  volume       = {7},
  year         = {2002},
}