ALMA-IMF VII : investigating the origin of stellar masses: CMF evolution in the W43-MM2&MM3 mini-starburst
Y. Pouteau ... [et al.].
Serie: Trabajos publicados del IAR ; no. 1718
Resumen: Among the most central open questions on the initial mass function (IMF) of stars is the impact of the environment on the shape of the core mass function (CMF) and thus potentially on the IMF. The ALMA-IMF Large Program aims to investigate the variations of the core distributions with cloud characteristics, as diagnostic observables of the formation process and evolution. The present study focuses on the W43-MM2&MM3 mini-starburst, whose CMF has been recently found to be top-heavy with respect to the Salpeter slope. W43-MM2&MM3 is a useful test case for environmental studies because it harbors a rich cluster containing a statistically significant number of cores, previously characterized in paper III. We applied a multiscale decomposition technique on the ALMA 1.3 mm and 3 mm continuum images to define six subregions. For each subregion we characterize the high column density probability distribution function, n-PDF, shape of the cloud gas using the 1.3 mm image. Using the core catalog, we investigate correlations between the CMF, n-PDF and core mass segregation. We classify the subregions into different stages of evolution, from quiescent to burst to post-burst, based on the surface number density of cores, number of outflows, and UCHii presence. The high-mass end of the subregion CMFs vary from being close to the Salpeter slope (quiescent) to top-heavy (burst and post-burst). Moreover, the second tail of the n-PDF varies from steep, to flat like observed for the high mass star-forming clouds. We found that subregions with flat second n-PDF tails display top-heavy CMFs. The CMF may evolve from Salpeter to top-heavy throughout the star formation process from the quiescent to the burst phase. This scenario raises the question of if the CMF might revert again to Salpeter as the cloud approaches the end of its star formation stage, a hypothesis that remains to be tested
