Invited review abstract
From filamentary clouds to prestellar cores to the stellar IMF: First results from the Herschel Gould Belt Survey
Abstract
The Herschel Space Observatory provides a unique opportunity to improve our global understanding of the earliest phases of star formation. I will present an overview of the first results from the Gould Belt survey, one of the largest key projects
with Herschel. The immediate objective of this SPIRE/PACS imaging survey is to obtain complete samples of nearby prestellar cores and Class 0 protostars with well characterized luminosities, temperatures, and density profiles, as well as robust core mass functions and protostar luminosity functions, in a variety of star-forming environments. Thanks to its high sensitivity and large spatial dynamic range, this survey can also probe, for the first time, the link between diffuse cirrus-like structures and compact self-gravitating cores. The main scientific goal is to elucidate the physical mechanisms responsible for the formation of prestellar cores out of the diffuse interstellar medium, which is crucial for understanding the origin of the stellar initial mass function. Our first results, obtained toward the Aquila Rift and Polaris Flare regions during the 'Science Demonstration Phase' of Herschel, are very promising (see A&A Vol. 518, special issue on Herschel). Based on these early results, I will discuss preliminary implications for our understanding of the formation mechanism of prestellar cores and the link between the prestellar core mass function and the stellar initial mass function. 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, probably as a result of interstellar MHD turbulence, and then the densest filaments fragment into a number of prestellar cores via gravitational instability.
with Herschel. The immediate objective of this SPIRE/PACS imaging survey is to obtain complete samples of nearby prestellar cores and Class 0 protostars with well characterized luminosities, temperatures, and density profiles, as well as robust core mass functions and protostar luminosity functions, in a variety of star-forming environments. Thanks to its high sensitivity and large spatial dynamic range, this survey can also probe, for the first time, the link between diffuse cirrus-like structures and compact self-gravitating cores. The main scientific goal is to elucidate the physical mechanisms responsible for the formation of prestellar cores out of the diffuse interstellar medium, which is crucial for understanding the origin of the stellar initial mass function. Our first results, obtained toward the Aquila Rift and Polaris Flare regions during the 'Science Demonstration Phase' of Herschel, are very promising (see A&A Vol. 518, special issue on Herschel). Based on these early results, I will discuss preliminary implications for our understanding of the formation mechanism of prestellar cores and the link between the prestellar core mass function and the stellar initial mass function. 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, probably as a result of interstellar MHD turbulence, and then the densest filaments fragment into a number of prestellar cores via gravitational instability.