Characterizing interstellar filaments with Herschel in IC5146

TL;DR

This study uses Herschel data to analyze the filamentary structures in the IC5146 molecular cloud, revealing a characteristic filament width of about 0.1 pc linked to turbulence dissipation.

Contribution

It provides the first detailed analysis of filament widths and density profiles in IC5146, suggesting a universal filament width related to turbulence scales.

Findings

Filaments have a median width of 0.10 ± 0.03 pc.

Density profiles fall off as r^{-1.5} to r^{-2.5}.

Filament widths are consistent with turbulence dissipation scales.

Abstract

We provide a first look at the results of the Herschel Gould Belt survey toward the IC5146 molecular cloud and present a preliminary analysis of the filamentary structure in this region. The column density map, derived from our 70-500 micron Herschel data, reveals a complex network of filaments, and confirms that these filaments are the main birth sites of prestellar cores. We analyze the column density profiles of 27 filaments and show that the underlying radial density profiles fall off as r^{-1.5} to r^{-2.5} at large radii. Our main result is that the filaments seem to be characterized by a narrow distribution of widths having a median value of 0.10 +- 0.03 pc, which is in stark contrast to a much broader distribution of central Jeans lengths. This characteristic width of ~0.1 pc corresponds to within a factor of ~2 to the sonic scale below which interstellar turbulence becomes subsonic in diffuse gas, supporting the argument that the filaments may form as a result of the dissipation of large-scale turbulence.