The VMC Survey. XXIX. Turbulence-controlled hierarchical star formation in the Small Magellanic Cloud

Ning Chen Sun, Richard De Grijs, Maria-Rosa L. Cioni, Stefano Rubele, Smitha Subramanian, Jacco Th van Loon, Kenji Bekki, Cameron P.M. Bell, Valentin D. Ivanov, Marcella Marconi, Tatiana Muraveva, Joana M. Oliveira, Vincenzo Ripepi

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    30 Citations (Scopus)
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    Abstract

    In this paper we report a clustering analysis of upper main-sequence stars in the Small Magellanic Cloud, using data from the VMC survey (the VISTA near-infrared YJK s survey of the Magellanic system). Young stellar structures are identified as surface overdensities on a range of significance levels. They are found to be organized in a hierarchical pattern, such that larger structures at lower significance levels contain smaller ones at higher significance levels. They have very irregular morphologies, with a perimeter-area dimension of 1.44 ± 0.02 for their projected boundaries. They have a power-law mass-size relation, power-law size/mass distributions, and a log-normal surface density distribution. We derive a projected fractal dimension of 1.48 ± 0.03 from the mass-size relation, or of 1.4 ± 0.1 from the size distribution, reflecting significant lumpiness of the young stellar structures. These properties are remarkably similar to those of a turbulent interstellar medium, supporting a scenario of hierarchical star formation regulated by supersonic turbulence.

    Original languageEnglish
    Article number31
    Pages (from-to)1-15
    Number of pages15
    JournalAstrophysical Journal
    Volume858
    Issue number1
    DOIs
    Publication statusPublished - 3 May 2018

    Bibliographical note

    Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

    Keywords

    • galaxies: star clusters: general
    • infrared: stars
    • Magellanic Clouds
    • stars: formation

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