Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1S021

Complex kinematics in a highly filamentary IRDC

Henshaw, Jonathan D. (University of Leeds, UK)
Caselli, Paola (University of Leeds, UK)
Jimenez-Serra, Izaskun (European Southern Observatory, Germany)
Fontani, Francesco (Osservatorio Astrofisico di Arcetri, Italy)
Tan, Jonathan C. (University of Florida, USA)

Infrared Dark Clouds (IRDCs) are excellent environments within which we can study the initial condtions of high-mass stars and stellar cluster formation. High spectral and angular resolution observations of molecular gas tracers towards IRDCs are needed to study in detail their physical properties and dynamics. In this poster we present high-sensitivity and high-angular resolution N2H+ (1-0) observations of a highly-filamentary IRDC, G035.39-00.33, taken with the Plateau de Bure Interferometer. Our study reveals that G035.39-00.33 is comprised of several filamentary structures that can be resolved both spectrally and spatially. These filamentary structures are separated in velocity by ~ 1 km s-1. Typical linewidths are found to be between 0.5-1.5 km s-1, indicating that the gas motions are supersonic throughout the mapped region. We find that whilst the global kinematics of the filaments are typically quiescent (showing small overall velocity gradients), the kinematics of localised regions are highly dynamic. Our results suggest that opposing velocity flows (velocity gradient ~ 2.5kms-1pc-1) are directed towards H6, the most massive core located in the region. This may be a signature of the on-going accumulation of material toward H6. In addition, we find via the analysis of position-velocity slices perpendicular to the major axis of the IRDC structure, that there exists relative shear motions between the two main filamentary components (magnitude ~ 13kms-1pc-1). The shear motion between these two closely related filamentary structures could be an observational signature of the cloud formation process.

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