EPoS Contribution
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The Core Mass Function in the Galactic Center
Alva Kinman Chalmers, Gothenburg, SE | |
The origin of the Initial Mass Function (IMF) of stars is still under debate. Certain star formation theories involve a close connection between the IMF and the Core Mass Function (CMF) and early observational results found the CMF to be similar in shape to the IMF. However, in recent years, CMFs of some more distant star-forming regions have been reported that differ from the Salpeter IMF. Here we study the CMF of three clouds in the Central Molecular Zone (CMZ): G0.253+0.016 ("The Brick"), Sgr B2 (Deep South field) and Sgr C. We use Band 6 continuum images from the Atacama Large Millimeter/submillimeter Array (ALMA) archive and identify cores as peaks in thermal dust emission via the dendrogram algorithm. Completeness corrections are applied, derived using synthetic core insertion and recovery. The synthetic cores are given mass-dependent radii derived from observed core radii. After corrections, a power law of the form dN/dlog M ∝ M-α is fit to the CMFs above 2 solar masses. The three regions are different, with the Brick showing a Salpeter-like power law index α=1.21±0.11 and the other two regions showing shallower slopes (α=0.92±0.09 for Sgr C and α=0.66±0.05 for Sgr B2-DS). Furthermore, we analyze the spatial distribution of cores, calculating both the Q parameter and mass segregation parameter for each region. Sgr C and Sgr B2-DS show signs of mass segregation, but the Brick does not. The results could be explained by a model in which cores grow in mass by accreting from the surrounding clump, and the differences between the regions could be related to their evolutionary stage. | |
Caption: Core mass functions for The Brick (left), Sgr C (middle) and Sgr B2 Deep South (right). The black histogram shows the "raw" CMF, the blue histogram shows the flux corrected CMF and the red histogram shows the number corrected CMF. Lines are fitted using the weighted least squares method to mass bins above 2 solar masses. | |
Collaborators: M. Petkova, Chalmers, SE J. Tan, Chalmers, SE and UVA, US G. Cosentino, ESO Y. Cheng, NAOJ, JP |
Relevant topic(s): Clustered SF Core MF |
Relevant Big Question: Is the core mass function universal? |