2010/01/31 by Mark R. Krumholz, Andrew J. Cunningham, A. J. Cunningham +3 · 4 citations
Chemical Engineering · Physics and Astronomy · #Advanced Combustion Engine Technologies #Astrophysics #Astrophysics and Star Formation Studies #Fragmentation (computing) #Galaxy #Initial mass function #Interstellar medium #Molecular cloud #Physics #Radiative transfer #Star cluster #Star formation #Stars #Stellar, planetary, and galactic studies #Surface brightness #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/713/2/1120
14 pages, 8 figures, accepted to ApJ. Minor changes to discussion from version 1. Figure resolution degraded to fit within size limits. A full resolution version is available at http://www.ucolick.org/~krumholz/publications.html
arxiv created 2010/02/28 · openalex publication_date 2010/03/31 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The fragmentation of star-forming interstellar clouds, and the resulting stellar initial mass function (IMF), is strongly affected by the temperature structure of the collapsing gas. Since radiation feedback from embedded stars can modify this as collapse proceeds, feedback plays an important role in determining the IMF. However, the effects and importance of radiative heating are likely to depend strongly on the surface density of the collapsing clouds, which determines both their effectiveness at trapping radiation and the accretion luminosities of the stars forming within them. In this paper, we report a suite of adaptive mesh refinement radiation–hydrodynamic simulations using the ORION code in which we isolate the effect of column density on fragmentation by following the collapse of clouds of varying column density while holding the mass, initial density and velocity structure, and initial virial ratio fixed. We find that radiation does not significantly modify the overall star formation rate or efficiency, but that it suppresses fragmentation more and more as cloud surface densities increase from those typical of low-mass star-forming regions like Taurus, through the typical surface density of massive star-forming clouds in the Galaxy, up to conditions found only in super-star clusters. In regions of low surface density, fragmentation during collapse leads to the formation of small clusters rather than individual massive star systems, greatly reducing the fraction of the stellar population with masses ≳10 M ☉ . Our simulations have important implications for the formation of massive stars and the universality of the IMF.