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PI: Philippe André
Co-PI: Paolo Saraceno Members: A. Abergel, P. Ade, J.-P. Baluteau, M. Benedettini, J.-Ph. Bernard, J. Blommaert, S. Bontemps, L. Cambrésy, P. Cox, P. Didelon, J. Di Francesco, A. Di Giorgio, M. Griffin, P. Hargrave, Th. Henning, M. Huang, J. Kirk, O. Krause, R. Launhardt, S. Leeks, J. Li, P. Martin, A. Men’shchikov, B. Merín, V. Minier, S. Molinari, F. Motte, G. Olofsson, A. Omont, S. Pezzuto, T. Prusti, P. Royer, D. Russeil, M. Sauvage , N. Schneider, B. Sibthorpe , A. Sicilia-Aguilar, L. Spinoglio, L. Testi, R. Vavrek, C. Waelkens, D. Ward-Thompson, G. White, C. Wilson, A. Woodcraft, A. Zavagno Features 461 hours |
Probing the origin of the stellar initial mass function:
A wide-field Herschel photometric survey of nearby star-forming cloud complexes Herschel provides a unique
opportunity to study the earliest stages of star formation. What is the
origin of the stellar initial mass function (IMF)? This issue is
central in local star formation research and for understanding whether
the IMF is truly universal or is likely to depend on metallicity,
pressure, or temperature. As prestellar cores and young (Class 0)
protostars emit the bulk of their luminosity at ~80-400 microns, the
Herschel imaging instruments SPIRE and PACS are ideal for takinga
census of such objects down to ~0.01-0.1 Msun in the nearby (0.5 kpc)
molecular cloud complexes. We propose an extensive imaging survey of
the densest portions of the Gould Belt with SPIRE at 250-500 and PACS
at 110-170 microns down to a 5-sigma column sensitivity NH2~1021 cm^-2
or Av~1. Our goal is to make a complete, homogeneous mapping of the
Av>3 regions with SPIRE and of the Av>6 regions with PACS, and
representative areas at Av~1-3 levels with both instruments. The survey
sensitivity is well matched to the expected cirrus confusion limit, so
we should detect structures throughout the maps. The target clouds span
a range of physical conditions, from active, cluster-forming complexes
to quiescent regions with lower star formation activity. We should
detect hundreds Class 0 protostars and thousands prestellar
condensations in the entire ~145 deg^2 SPIRE survey, i.e. ~10 times
more cold objects than already identified from the ground. These
numbers should allow us to derive an accurate prestellar core mass
function. The temperature and density structures
of the nearest ( 0.2 kpc) cores will be resolved, revealing the initial
conditions for individual protostellar collapse. The large spatial
dynamic range of the proposed survey will probe the link between
diffuse cirrus-like structures and compact self-gravitating cores. Our
main scientific goal is to elucidate the physical mechanisms for the
formation of prestellar cores out of the diffuse medium, crucial for
understanding the origin of stellar masses.
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| Editor: Vincent Minier
Last update: 02/01/2008 |
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