SDC13 infrared dark clouds: Longitudinally collapsing filaments?
Résumé
Formation of stars is now believed to be tightly linked to the dynamical evolution of
interstellar filaments in which they form. In this paper we analyze the density structure
and kinematics of a small network of infrared dark filaments, SDC13, observed in both dust
continuum and molecular line emission with the IRAM 30 m telescope. These observations
reveal the presence of 18 compact sources amongst which the two most massive, MM1 and MM2,
are located at the intersection point of the parsec-long filaments. The dense gas velocity
and velocity dispersion observed along these filaments show smooth, strongly correlated,
gradients. We discuss the origin of the SDC13 velocity field in the context of filament
longitudinal collapse. We show that the collapse timescale of the SDC13 filaments (from 1
Myr to 4 Myr depending on the model parameters) is consistent with the presence of Class I
sources in them, and argue that, on top of bringing more material to the centre of the
system, collapse could generate additional kinematic support against local fragmentation,
helping the formation of starless super-Jeans cores.
| Origine | Publication financée par une institution |
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