Testing massive star evolution, star-formation history, and feedback at low metallicity
| Autor: | Leah M. Fulmer, John S. Gallagher, Wolf-Rainer Hamann, Lida M. Oskinova, Varsha Ramachandran |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| Zdroj: | Web of Science |
| ISSN: | 1432-0746 0004-6361 |
| Popis: | The supergiant ionized shell SMC-SGS 1 (DEM 167), located in the outer Wing of the Small Magellanic Cloud (SMC), resembles structures that originate from an energetic star-formation event and later stimulate star formation as they expand into the ambient medium. However, stellar populations within and surrounding SMC-SGS 1 tell a different story. We present a photometric study of the stellar population encompassed by SMC-SGS 1 in order to trace the history of this structure and its potential influence on star formation within the low-density, low-metallicity SMC Wing. For a stellar population that is physically associated with SMC-SGS 1, we combined near-ultraviolet (NUV) photometry from the Galaxy Evolution Explorer (GALEX) with archival optical (V-band) photometry from the ESO Danish 1.54m Telescope. Given their colors and luminosities, we estimated stellar ages and masses by matching observed photometry to theoretical stellar isochrone models. We find that the investigated region supports an active, extended star-formation event spanning $\sim$ 25 - 40 Myr ago, as well as continued star formation into the present. Using a standard initial mass function (IMF), we infer a lower bound on the stellar mass from this period of $\sim 3 \times 10^4 M_{\odot}$, corresponding to a star-formation intensity of $\sim$ 6 $\times$ 10$^{-3}$ M$_{\odot}$ kpc$^{-2}$ yr$^{-1}$. The spatial and temporal distributions of young stars encompassed by SMC-SGS 1 imply a slow, consistent progression of star formation over millions of years. Ongoing star formation along the edge of and interior to SMC-SGS 1 suggests a combined stimulated and stochastic mode of star formation within the SMC Wing. A slow expansion of the shell within this low-density environment may preserve molecular clouds within the volume of the shell, leaving them to form stars even after nearby stellar feedback expels local gas and dust. Comment: 9 pages, 6 figures, 3 tables |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|