TY - JOUR
T1 - Dusty Cloud Acceleration by Radiation Pressure in Rapidly Star-forming Galaxies
AU - Zhang, Dong
AU - Davis, Shane W.
AU - Jiang, Yan Fei
AU - Stone, James McLellan
N1 - Funding Information:
We thank Todd Thompson, Daniel Proga, Peng Oh, Mike McCourt, Sylvain Veilleux, Eliot Quataert, Norm Murray, Tim Waters, Suoqing Ji, Patrick Hall, Ari Laor, and Sebastian Hoenig for stimulating discussions. This work used the computational resources provided by the Advanced Research Computing Services (ARCS) at the University of Virginia. We also used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation (NSF) grant No. ACI-1053575. S.W.D. and D.Z. acknowledge support from NSF grant AST-1616171 and an Alfred P. Sloan Research Fellowship. Y.F.J. is supported in part by the National Science Foundation under grant No. NSF PHY 17-48958. J.M.S. is supported by NSF grant AST-1333091.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/2/20
Y1 - 2018/2/20
N2 - We perform two-dimensional and three-dimensional radiation hydrodynamic simulations to study cold clouds accelerated by radiation pressure on dust in the environment of rapidly star-forming galaxies dominated by infrared flux. We utilize the reduced speed of light approximation to solve the frequency-averaged, time-dependent radiative transfer equation. We find that radiation pressure is capable of accelerating the clouds to hundreds of kilometers per second while remaining dense and cold, consistent with observations. We compare these results to simulations where acceleration is provided by entrainment in a hot wind, where the momentum injection of the hot flow is comparable to the momentum in the radiation field. We find that the survival time of the cloud accelerated by the radiation field is significantly longer than that of a cloud entrained in a hot outflow. We show that the dynamics of the irradiated cloud depends on the initial optical depth, temperature of the cloud, and intensity of the flux. Additionally, gas pressure from the background may limit cloud acceleration if the density ratio between the cloud and background is ≲102. In general, a 10 pc-scale optically thin cloud forms a pancake structure elongated perpendicular to the direction of motion, while optically thick clouds form a filamentary structure elongated parallel to the direction of motion. The details of accelerated cloud morphology and geometry can also be affected by other factors, such as the cloud lengthscale, reduced speed of light approximation, spatial resolution, initial cloud structure, and dimensionality of the run, but these have relatively little affect on the cloud velocity or survival time.
AB - We perform two-dimensional and three-dimensional radiation hydrodynamic simulations to study cold clouds accelerated by radiation pressure on dust in the environment of rapidly star-forming galaxies dominated by infrared flux. We utilize the reduced speed of light approximation to solve the frequency-averaged, time-dependent radiative transfer equation. We find that radiation pressure is capable of accelerating the clouds to hundreds of kilometers per second while remaining dense and cold, consistent with observations. We compare these results to simulations where acceleration is provided by entrainment in a hot wind, where the momentum injection of the hot flow is comparable to the momentum in the radiation field. We find that the survival time of the cloud accelerated by the radiation field is significantly longer than that of a cloud entrained in a hot outflow. We show that the dynamics of the irradiated cloud depends on the initial optical depth, temperature of the cloud, and intensity of the flux. Additionally, gas pressure from the background may limit cloud acceleration if the density ratio between the cloud and background is ≲102. In general, a 10 pc-scale optically thin cloud forms a pancake structure elongated perpendicular to the direction of motion, while optically thick clouds form a filamentary structure elongated parallel to the direction of motion. The details of accelerated cloud morphology and geometry can also be affected by other factors, such as the cloud lengthscale, reduced speed of light approximation, spatial resolution, initial cloud structure, and dimensionality of the run, but these have relatively little affect on the cloud velocity or survival time.
KW - ISM: jets and outflows
KW - galaxies: ISM
KW - hydrodynamics
KW - methods: numerical
KW - radiative transfer
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U2 - 10.3847/1538-4357/aaa8e4
DO - 10.3847/1538-4357/aaa8e4
M3 - Article
AN - SCOPUS:85042702928
SN - 0004-637X
VL - 854
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 110
ER -