The Core Mass Function across Galactic Environments. III. Massive Protoclusters
Journal article, 2021

The stellar initial mass function (IMF) is fundamental for many areas of astrophysics, but its origin remains poorly understood. It may be inherited from the core mass function (CMF) or arise as a result of more chaotic, competitive accretion. Dense, gravitationally bound cores are seen in molecular clouds and some observations have suggested that the CMF is similar in shape to the IMF, though translated to higher masses by a factor of similar to 3. Here we measure the CMF in 28 dense clumps within 3.5 kpc that are likely to be central regions of massive protoclusters, observed via 1.3 mm dust continuum emission by the ALMAGAL project. We identify 222 cores using the dendrogram algorithm with masses ranging from 0.04 to 252 M-circle dot. We apply completeness corrections for flux and number recovery, estimated from core insertion and recovery experiments. At higher masses, the final derived CMF is well described by a single power law of the form dN/d log M proportional to M-alpha alpha similar or equal to 0.94 +/- 0.08. However, we find evidence of a break in this power-law behavior between similar to 5 and 15 M-circle dot, which is, to our knowledge, the first time such a break has been found in distant (greater than or similar to 1 kpc) regions by the Atacama Large Millimeter/submillimeter Array. We compare this massive protocluster CMF with those derived using the same methods in the G286 protocluster and a sample of infrared dark clouds. The massive protocluster CMF is significantly different, i.e., containing more massive cores, which is a potential indication of the role of environment on the CMF and IMF.

Author

Theo J. O'Neill

University of Virginia

Giuliana Cosentino

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Extragalactic Astrophysics

Jonathan Tan

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

University of Virginia

Yu Cheng

University of Virginia

Mengyao Liu

University of Virginia

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 916 1 45

Massive Star Formation through the Universe (MSTAR)

European Commission (EC) (788829), 2018-09-01 -- 2023-08-31.

Subject Categories

Analytical Chemistry

Astronomy, Astrophysics and Cosmology

Geosciences, Multidisciplinary

DOI

10.3847/1538-4357/ac062d

More information

Latest update

8/17/2021