Philip F. Hopkins, Dusan Keres, Norman Murray, Eliot Quataert, Lars Hernquist
We use numerical simulations of isolated galaxies to study the effects of
realistic stellar feedback on the formation and evolution of giant star-forming
gas 'clumps' in high-redshift, gas-rich galaxies. Such galactic disks are
unstable to the formation of bound gas-rich clumps whose properties initially
depend only on global disk properties, not the microphysics of feedback. In
simulations without stellar feedback, clumps turn an order-unity fraction of
their mass into stars and sink to the center, forming a large bulge and kicking
most of the stars out into a much more extended stellar envelope. By contrast,
stellar feedback disrupts even the most massive clumps after they turn ~10-20%
of their mass into stars, in a timescale of ~10-100 Myr, ejecting some material
into a super-wind and recycling the rest of the gas into the diffuse ISM. This
suppresses the bulge formation rate by direct 'clump coalescence' by a factor
of several. However, the galactic disks do undergo significant secular
evolution in the absence of mergers: clumps form and disrupt continuously and
torque gas to the galactic center. The resulting evolution is qualitatively
similar to bar/spiral evolution in simulations with a more homogeneous ISM.
View original:
http://arxiv.org/abs/1111.6591
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