115 research outputs found
Toward the Formation of Realistic Galaxy Disks
In this review I demonstrate that a realistic model for the formation of
galaxy disks depends on a proper treatment of the gas in galaxies.
Historically, cosmological simulations of disk galaxy formation have suffered
from a lack of resolution and a physically motivated feedback prescription.
Recent computational progress has allowed for unprecedented resolution, which
in turn allows for a more realistic treatment of feedback. These advances have
led to a new examination of gas accretion, evolution, and loss in the formation
of galaxy disks. Here I highlight the role that gas inflows, the regulation of
gas by feedback, and gas outflows play in achieving simulated disk galaxies
that better match observational results as a function of redshift.Comment: Proceedings of the Frank N. Bash Symposium 2009: "New Horizons in
Astronomy." Comments welcome
Kinematic Evolution of Simulated Star-Forming Galaxies
Recent observations have shown that star-forming galaxies like our own Milky
Way evolve kinematically into ordered thin disks over the last ~8 billion years
since z=1.2, undergoing a process of "disk settling." For the first time, we
study the kinematic evolution of a suite of four state of the art "zoom in"
hydrodynamic simulations of galaxy formation and evolution in a fully
cosmological context and compare with these observations. Until now, robust
measurements of the internal kinematics of simulated galaxies were lacking as
the simulations suffered from low resolution, overproduction of stars, and
overly massive bulges. The current generation of simulations has made great
progress in overcoming these difficulties and is ready for a kinematic
analysis. We show that simulated galaxies follow the same kinematic trends as
real galaxies: they progressively decrease in disordered motions (sigma_g) and
increase in ordered rotation (Vrot) with time. The slopes of the relations
between both sigma_g and Vrot with redshift are consistent between the
simulations and the observations. In addition, the morphologies of the
simulated galaxies become less disturbed with time, also consistent with
observations, and they both have similarly large scatter. This match between
the simulated and observed trends is a significant success for the current
generation of simulations, and a first step in determining the physical
processes behind disk settling.Comment: ApJ accepted; 6 pages; A pdf with full resolution figures can be
found at https://db.tt/8y4Vzaff (2.8M
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