%0 Generic %1 Krumholz2011 %A Krumholz, Mark R. %A Klein, Richard I. %A McKee, Christopher F. %D 2011 %K RadTran imf star %T Radiation-Hydrodynamic Simulations of the Formation of Massive Star Clusters I. Implications for the Origin of the Initial Mass Function %U http://arxiv.org/abs/1104.2038 %X One model for the origin of typical galactic star clusters such as the Orion Nebula Cluster (ONC) is that they form via the rapid, efficient collapse of a bound gas clump within a larger, gravitationally-unbound giant molecular cloud. However, simulations in support of this scenario have thus far have not included the radiation feedback produced by the stars; radiative simulations have been limited to significantly smaller or lower density regions. Here we use the ORION adaptive mesh refinement code to conduct the first ever radiation-hydrodynamic simulations of the global collapse scenario for the formation of an ONC-like cluster. We show that radiative feedback has a dramatic effect on the evolution: once the first ~10-20% of the gas mass is incorporated into stars, their radiative feedback raises the gas temperature high enough to suppress any further fragmentation. However, gas continues to accrete onto existing stars, and, as a result, the stellar mass distribution becomes increasingly top-heavy. By the time ~40% of the mass has been accreted, roughly the minimum amount we expect if the collapse is to result in a bound cluster, the mass distribution is clearly inconsistent with the observed stellar initial mass function (IMF). We therefore conclude that the global collapse scenario, at least in its simplest form, is not compatible with the observed stellar IMF. We speculate that processes that slow down star formation, and thus reduce the accretion luminosity, may be able to resolve the problem.

@misc{Krumholz2011, abstract = { One model for the origin of typical galactic star clusters such as the Orion Nebula Cluster (ONC) is that they form via the rapid, efficient collapse of a bound gas clump within a larger, gravitationally-unbound giant molecular cloud. However, simulations in support of this scenario have thus far have not included the radiation feedback produced by the stars; radiative simulations have been limited to significantly smaller or lower density regions. Here we use the ORION adaptive mesh refinement code to conduct the first ever radiation-hydrodynamic simulations of the global collapse scenario for the formation of an ONC-like cluster. We show that radiative feedback has a dramatic effect on the evolution: once the first ~10-20% of the gas mass is incorporated into stars, their radiative feedback raises the gas temperature high enough to suppress any further fragmentation. However, gas continues to accrete onto existing stars, and, as a result, the stellar mass distribution becomes increasingly top-heavy. By the time ~40% of the mass has been accreted, roughly the minimum amount we expect if the collapse is to result in a bound cluster, the mass distribution is clearly inconsistent with the observed stellar initial mass function (IMF). We therefore conclude that the global collapse scenario, at least in its simplest form, is not compatible with the observed stellar IMF. We speculate that processes that slow down star formation, and thus reduce the accretion luminosity, may be able to resolve the problem. }, added-at = {2011-04-13T07:45:00.000+0200}, author = {Krumholz, Mark R. and Klein, Richard I. and McKee, Christopher F.}, biburl = {https://www.bibsonomy.org/bibtex/2c38d18c1bb8f0c5e1360e0c9430faab0/miki}, description = {[1104.2038] Radiation-Hydrodynamic Simulations of the Formation of Massive Star Clusters I. Implications for the Origin of the Initial Mass Function}, interhash = {8f6b321f480d5af96f465fda9671a92b}, intrahash = {c38d18c1bb8f0c5e1360e0c9430faab0}, keywords = {RadTran imf star}, note = {cite arxiv:1104.2038 Comment: 15 pages, 11 figures, submitted to ApJ}, timestamp = {2011-04-13T07:45:01.000+0200}, title = {Radiation-Hydrodynamic Simulations of the Formation of Massive Star Clusters I. Implications for the Origin of the Initial Mass Function}, url = {http://arxiv.org/abs/1104.2038}, year = 2011 }