Fragmentation of massive dense cores down to ≲ 1000 AU: relation between fragmentation and density structure

From National Research Council Canada

DOI	Resolve DOI: https://doi.org/10.1088/0004-637X/785/1/42
Author	Search for: Palau, Aina; Search for: Estalella, Robert; Search for: Girart, Josep M.; Search for: Fuente, Asuncion; Search for: Fontani, Francesco; Search for: Commerçon, Benoit; Search for: Busquet, Gemma; Search for: Bontemps, Sylvain; Search for: Sánchez-Monge, Álvaro; Search for: Zapata, Luis A.; Search for: Zhang, Qizhou; Search for: Hennebelle, Patrick; Search for: Di Francesco, James¹
Affiliation	National Research Council of Canada. National Science Infrastructure
Format	Text, Article
Subject	galaxies: star clusters: general; radio continuum: ISM; stars: formation; techniques: high angular resolution
Abstract	In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.
Publication date	2014-03-25
Publisher	American Astronomical Society IOP Publishing
In	The Astrophysical Journal 785, no. 1, 42: 1–18.
Language	English
Peer reviewed	Yes
NPARC number	21272705
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Record identifier	ab951181-25c6-46fc-b215-04be891867b6
Record created	2014-12-03
Record modified	2020-04-22

Date modified:: 2024-07-17