The VMC Survey. XXVII. Young Stellar Structures in the LMC’s Bar Star-forming Complex
| Autor: | Marcella Marconi, Stefano Rubele, Vincenzo Ripepi, Valentin D. Ivanov, Ben L. Tatton, Jacco Th. van Loon, Smitha Subramanian, Joana M. Oliveira, Cameron P. M. Bell, Andrés E. Piatti, Richard de Grijs, Ning-Chen Sun, Kenji Bekki, Maria-Rosa L. Cioni |
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| Jazyk: | angličtina |
| Předmět: |
Magnitude (mathematics)
FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences MAGELLANIC CLOUDS FORMATION [STARS] QB460 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Large Magellanic Cloud 010303 astronomy & astrophysics Stellar density Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Physics 010308 nuclear & particles physics Star formation STARS [INFRARED] Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies Stars Star cluster Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Log-normal distribution Substructure Astrophysics::Earth and Planetary Astrophysics |
| Zdroj: | The Astrophysical Journal CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET |
| ISSN: | 1538-4357 0004-6361 1286-4846 0035-8711 0004-637X 1538-3881 0004-6264 0067-0049 1538-3873 |
| DOI: | 10.3847/1538-4357/aa911e |
| Popis: | Star formation is a hierarchical process, forming young stellar structures of star clusters, associations, and complexes over a wide scale range. The star-forming complex in the bar region of the Large Magellanic Cloud is investigated with upper main-sequence stars observed by the VISTA Survey of the Magellanic Clouds. The upper main-sequence stars exhibit highly non-uniform distributions. Young stellar structures inside the complex are identified from the stellar density map as density enhancements of different significance levels. We find that these structures are hierarchically organized such that larger, lower-density structures contain one or several smaller, higher-density ones. They follow power-law size and mass distributions as well as a lognormal surface density distribution. All these results support a scenario of hierarchical star formation regulated by turbulence. The temporal evolution of young stellar structures is explored by using subsamples of upper main-sequence stars with different magnitude and age ranges. While the youngest subsample, with a median age of log($\tau$/yr)~=~7.2, contains most substructure, progressively older ones are less and less substructured. The oldest subsample, with a median age of log($\tau$/yr)~=~8.0, is almost indistinguishable from a uniform distribution on spatial scales of 30--300~pc, suggesting that the young stellar structures are completely dispersed on a timescale of $\sim$100~Myr. These results are consistent with the characteristics of the 30~Doradus complex and the entire Large Magellanic Cloud, suggesting no significant environmental effects. We further point out that the fractal dimension may be method-dependent for stellar samples with significant age spreads. Comment: 17 pages, 15 figures. Accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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