Journal article
The evolution of stellar structures in dwarf galaxies
Monthly notices of the Royal Astronomical Society, Vol.412(3), pp.1539-1551
04/2011
DOI: 10.1111/j.1365-2966.2010.17841.x
Abstract
We present a study of the variation of spatial structure of stellar populations within dwarf galaxies as a function of the population age. We use deep Hubble Space Telescope/Advanced Camera for Surveys imaging of nearby dwarf galaxies in order to resolve individual stars and create composite colour-magnitude diagrams (CMDs) for each galaxy. Using the obtained CMDs, we select blue helium burning stars, which can be unambiguously age-dated by comparing the absolute magnitude of individual stars with stellar isochrones. Additionally, we select a very young (less than or similar to 10 Myr) population of OB stars for a subset of the galaxies based on the tip of the young main sequence. By selecting stars in different age ranges, we can then study how the spatial distribution of these stars evolves with time. We find, in agreement with previous studies, that stars are born within galaxies with a high degree of substructure which is made up of a continuous distribution of clusters, groups and associations from parsec to hundreds of parsec scales. These structures disperse on time-scales of tens to hundreds of Myr, which we quantify using the two-point correlation function and the Q-parameter developed by Cartwright & Whitworth. On galactic scales, we can place lower limits on the time it takes to remove the original structure (i.e. structure survives for at least this long), t(evo), which varies between similar to 100 Myr (NGC 2366) and similar to 350 Myr (DDO 165). This is similar to what we have found previously for the Small Magellanic Cloud (similar to 80 Myr) and the Large Magellanic Cloud (similar to 175 Myr). We do not find any strong correlations between t(evo) and the luminosity of the host galaxy.
Details
- Title: Subtitle
- The evolution of stellar structures in dwarf galaxies
- Creators
- N. Bastian - University of ExeterD. R. Weisz - University of MinnesotaE. D. Skillman - University of MinnesotaK. B. W. McQuinn - University of MinnesotaA. E. Dolphin - RTXR. A. Gutermuth - University of Massachusetts AmherstJ. M. Cannon - Macalester CollegeB. Ercolano - University of ExeterM. Gieles - Institute of AstronomyR. C. Kennicutt - Purple Mountain ObservatoryF. Walter - Max Planck Institute for Astronomy
- Resource Type
- Journal article
- Publication Details
- Monthly notices of the Royal Astronomical Society, Vol.412(3), pp.1539-1551
- Publisher
- Oxford Univ Press
- DOI
- 10.1111/j.1365-2966.2010.17841.x
- ISSN
- 0035-8711
- eISSN
- 1365-2966
- Number of pages
- 13
- Grant note
- Space Telescope Science Institute ST/H00243X/1 / Science and Technology Facilities Council; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) ST/F008600/2 / STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) GO-10605; NAS5-26555 / NASA; National Aeronautics & Space Administration (NASA) STFC advanced fellowship; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) Royal Society
- Language
- English
- Date published
- 04/2011
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627230702771
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