A millimeter continuum view of the Aquila Rift complex. Probing the properties of star formation in two active protoclusters: Serpens South and W40.
Ph. André, A. Men'shchikov, V. Könyves, S. Bontemps
We propose to present our analysis of the Aquila Rift complex (Maury et al. 2011), which addresses the questions of the star formation rate (SFR), star formation efficiency (SFE) and typical lifetime of the Class 0 protostellar phase in two nearby cluster-forming clumps: the Serpens South and W40 protoclusters. We carried out a 1.2 mm dust continuum follow-up mapping of the Aquila Rift, from which we perform a systematic source extraction. Based on complementary data from the Herschel Gould Belt survey and Spitzer maps, we characterize the spectral energy distributions of the millimeter continuum sources detected, and estimate their evolutionary stages. Taking advantage of the comprehensive dataset available for the Serpens South region, spanning wavelengths from 2 microns to 1.2 mm, we estimate the numbers of young stellar objects (YSOs) at different evolutionary stages.
Our unmatched census of YSOs in the Serpens South protocluster allows us to determine robust values for the ratio of Class 0 to Class I protostars N(0)/N(I) and the Class 0 lifetime. We will show that our results support a scenario of relatively fast accretion at the beginning of the protostellar phase, and challenge the recent Spitzer results by Evans et al. (2009).
We also show that, while the formation of the Serpens South and W40 protoclusters is likely to have been initiated in a very different manner, both are characterized by large fractions of protostars and high SFRs. They are active sites of clustered star formation currently undergoing bursts of star formation, and have the potential ability to form bound star clusters.