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

RFG Wyse, G Gilmore, ML Houdashelt, Sofia Feltzing, L Hebb, JS Gallagher, TA Smecker-Hane

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskriftPeer review

52 Citeringar (SciVal)

Sammanfattning

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.
Originalspråkengelska
Sidor (från-till)395-433
TidskriftNew Astronomy
Volym7
Utgåva7
DOI
StatusPublished - 2002

Ämnesklassifikation (UKÄ)

  • Astronomi, astrofysik och kosmologi

Fingeravtryck

Utforska forskningsämnen för ”Faint stars in the Ursa Minor dwarf spheroidal galaxy: implications for the low-mass stellar initial mass function at high redshift”. Tillsammans bildar de ett unikt fingeravtryck.

Citera det här