Exact Solutions and Scalar Fields in Gravity - Instituto Avanzado de ...

Adaptive Calculation of a Collapsing Molecular Cloud Core 229
of radiative transfer and assume the collapse to remain isothermal at
densities higher than in order to test the ability of the
code to reproduce the filamentary collapse solution expected at high
spatial resolution. Since the collapse is calculated in the zooming grid,
the radial cell sizes in the ordinary coordinates shrink in proportion to
the time difference When is smaller, the central cloud region is
zoomed with higher magnification. A value of is enough to
ensure sufficient high resolution to resolve the Jeans length through
7 orders of magnitude increase in density.
During the first free-fall time, the cloud collapses slowly to form a
rotationally supported disk about the equatorial plane. In this phase,
the gas is mainly seen to flow outwards in the zooming coordinates corresponding
to a general mild infall in the ordinary coordinates. After
about the collapse of the central cloud regions becomes progressively
more pronounced leading to a more rapid increase of the central
density contrast. The zooming radial velocity inside the
disk decreases as increases in magnitude compared to As the
central collapse continues to even higher densities, these terms roughly
balance making When this occurs, the central cloud region