Journal article
THE NATURE OF STARBURSTS. I. THE STAR FORMATION HISTORIES OF EIGHTEEN NEARBY STARBURST DWARF GALAXIES
The Astrophysical journal, Vol.721(1), pp.297-317
09/20/2010
DOI: 10.1088/0004-637X/721/1/297
Abstract
We use archival Hubble Space Telescope observations of resolved stellar populations to derive the star formation histories (SFHs) of 18 nearby starburst dwarf galaxies. In this first paper, we present the observations, color-magnitude diagrams (CMDs), and the SFHs of the 18 starburst galaxies, based on a homogeneous approach to the data reduction, differential extinction, and treatment of photometric completeness. We adopt a star formation rate (SFR) threshold normalized to the average SFR of the individual system as a metric for classifying starbursts in SFHs derived from resolved stellar populations. This choice facilitates finding not only the currently bursting galaxies but also "fossil" bursts increasing the sample size of starburst galaxies in the nearby (D < 8 Mpc) universe. Thirteen of the eighteen galaxies are experiencing ongoing bursts and five galaxies show fossil bursts. From our reconstructed SFHs, it is evident that the elevated SFRs of a burst are sustained for hundreds of Myr with variations on small timescales. A long > 100 Myr temporal baseline is thus fundamental to any starburst definition or identification method. The longer lived bursts rule out rapid "self-quenching" of starbursts on global scales. The bursting galaxies' gas consumption timescales are shorter than the Hubble time for all but one galaxy confirming the short-lived nature of starbursts based on fuel limitations. Additionally, we find that the strength of the Ha emission usually correlates with the CMD-based SFR during the last 4-10 Myr. However, in four cases, the Ha emission is significantly less than what is expected for models of starbursts; the discrepancy is due to the SFR changing on timescales of a few Myr. The inherently short timescale of the Ha emission limits identifying galaxies as starbursts based on the current characteristics which may or may not be representative of the recent SFH of a galaxy.
Details
- Title: Subtitle
- THE NATURE OF STARBURSTS. I. THE STAR FORMATION HISTORIES OF EIGHTEEN NEARBY STARBURST DWARF GALAXIES
- Creators
- Kristen B. W. McQuinn - University of MinnesotaEvan D. Skillman - University of MinnesotaJohn M. Cannon - Macalester CollegeJulianne Dalcanton - University of WashingtonAndrew Dolphin - RTXSebastian Hidalgo-Rodriguez - Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, SpainJon Holtzman - New Mexico State UniversityDavid Stark - University of MinnesotaDaniel Weisz - University of MinnesotaBenjamin Williams - University of Washington
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.721(1), pp.297-317
- Publisher
- Iop Publishing Ltd
- DOI
- 10.1088/0004-637X/721/1/297
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Number of pages
- 21
- Grant note
- ST/H001913/1 / STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) NAS 5-26555 / NASA; National Aeronautics & Space Administration (NASA) University of Minnesota; University of Minnesota System AR-10945; AR-11281 / Space Telescope Science Institute ST/H001913/1 / Science and Technology Facilities Council; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC)
- Language
- English
- Date published
- 09/20/2010
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627297102771
Metrics
1 Record Views