S. S. R. Offner, E. J. Lee, A. A. Goodman, H. Arce
We present results from three-dimensional, self-gravitating,
radiation-hydrodynamic simulations of low-mass protostellar outflows. We
construct synthetic observations in 12CO in order to compare with observed
outflows and evaluate the effects of beam resolution and outflow orientation on
inferred outflow properties. To facilitate the comparison, we develop a
quantitative prescription for measuring outflow opening angles. Using this
prescription, we demonstrate that, in both simulations and synthetic
observations, outflow opening angles broaden with time similarly to observed
outflows. However, the interaction between the outflowing gas and the turbulent
core envelope produces significant asymmetry between the red and blue shifted
outflow lobes. We find that applying a velocity cutoff may result in outflow
masses that are underestimated by a factor 5 or more, and masses derived from
optically thick CO emission further underpredict the mass of the high-velocity
gas by a factor of 5-10. Derived excitation temperatures indicate that
outflowing gas is hotter than the ambient gas with temperature rising over
time, which is in agreement with the simulation gas temperatures. However,
excitation temperatures are otherwise not well correlated with the actual gas
temperature.
View original:
http://arxiv.org/abs/1110.5640
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