From Herschel to ALMA : new insights into the physics of Class 0 protostars

Séminaire IPAG de Anaëlle Maury (ALMA fellow, ESO, Garching), jeudi 15 décembre 2011 à 11h00, IPAG seminar room

The launch of the Herschel submillimeter space observatory and the beginning of ALMA science operations have recently opened new windows for our exploration of the early phases of star formation. In this talk, I will describe the two main projects we’ve been carrying out in the last year to try better understanding the physics at work during the Class 0 phase, which is believed to represent the very first step of protostellar formation.

First I will present a study aiming at improving our knowledge of the earliest phases of clustered star formation, at large scales. I used MAMBO, Spitzer and Herschel Gould Belt survey maps of two prominent cluster-forming clumps in the Aquila Rift complex to characterize the evolutionary stage of the protostellar populations in these two protoclusters. I will show that our findings support a scenario of relatively fast accretion during the Class 0 protostellar phase, and suggest that the detailed manner in which the gravitational collapse has been initiated in those two protoclusters does not affect much the ability of a these clumps to form stars.

In a second part, I will present the high angular resolution studies of Class 0 protostars I carry out with both SMA & PdBI, and describe our surprising findings regarding the formation mechanisms of circumstellar disks and multiple systems at the Class 0 stage. I will also briefly present our PdBI Large Observing Program targeting an unprecedented large sample of 17 nearby low-mass Class 0 protostars. I will show some first preliminary observations obtained this year, and describe how this dataset will help us using efficiently ALMA capabilities to extend this pathfinder survey to the new large unbiased sample of Class 0 protostars unveiled by the Herschel Gould Belt survey.