From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey

TL;DR

This paper presents initial Herschel survey results revealing filamentary structures and dense cores in molecular clouds, showing a strong link between core mass functions and the stellar initial mass function, supporting a filament fragmentation formation scenario.

Contribution

It provides the first large-scale statistical comparison of prestellar core mass functions with the stellar IMF using Herschel data, confirming the filamentary origin of cores.

Findings

Prestellar core mass function in Aquila resembles the stellar IMF.

Filamentary structures are prevalent and linked to core formation.

A scenario where filaments fragment into cores via gravitational instability.

Abstract

We summarize the first results from the Gould Belt survey, obtained toward the Aquila Rift and Polaris Flare regions during the 'science demonstration phase' of Herschel. Our 70-500 micron images taken in parallel mode with the SPIRE and PACS cameras reveal a wealth of filamentary structure, as well as numerous dense cores embedded in the filaments. Between ~ 350 and 500 prestellar cores and ~ 45-60 Class 0 protostars can be identified in the Aquila field, while ~ unbound starless cores and no protostars are observed in the Polaris field. The prestellar core mass function (CMF) derived for the Aquila region bears a strong resemblance to the stellar initial mass function (IMF), already confirming the close connection between the CMF and the IMF with much better statistics than earlier studies. Comparing and contrasting our Herschel results in Aquila and Polaris, we propose an observationally-driven scenario for core formation according to which complex networks of long, thin filaments form first within molecular clouds, and then the densest filaments fragment into a number of prestellar cores via gravitational instability.