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The Impact of Feedback on Disk Galaxy Scaling Relations
| Content Provider | Semantic Scholar |
|---|---|
| Author | Dutton, Aaron A. Bosch, Frank C. Van Den |
| Copyright Year | 2009 |
| Abstract | We use a disk galaxy evolution model to investigate the impact of mass outflows (a.k.a. feedback) on disk galaxy scaling relations, mass fractions and spin parameters. Our model follows the accretion, cooling, star formation and ejection of baryonic mass inside growing dark matter haloes, with cosmologically motivated angular momentum distributions. Models without feedback produce disks that are too small and rotate too fast. Feedback reduces the galaxy formation efficiency, ǫGF, (defined as the fraction of the universally available baryons that end up as stars and cold gas in a given galaxy), resulting in larger disks with lower rotation velocities. Models with feedback can reproduce the zero points of the scaling relations between rotation velocity, stellar mass and disk size, but only in the absence of adiabatic contraction. Our feedback mechanism is maximally efficient in expelling mass, but our successful models require 25% of the SN energy, or 100% of the SN momentum, to drive an outflow. It remains to be seen whether such high efficiencies are realistic or not. Our energy and momentum driven wind models result in different slopes of various scaling relations. Energy driven winds result in steeper slopes to the galaxy mass halo mass, and stellar mass halo mass relations, a shallower slope to the galaxy size stellar mass relation at z = 0, and a steeper slope to the cold gas metallicity stellar mass relation at z ≃ 2. Observations favor the energy driven wind at stellar masses below Mstar ∼ < 10M⊙, but the momentum driven wind model at high masses. The ratio between the specific angular momentum of the baryons to that of the halo, (jgal/mgal), is not unity in our models with inflow and outflow. Yet this is the standard assumption in models of disk formation. Above a halo mass of Mvir ≃ 10 M⊙, cooling becomes increasingly inefficient, which results in (jgal/mgal) decreasing with increasing halo mass. Below a halo mass of Mvir ≃ 10 M⊙, feedback becomes increasingly efficient. Feedback preferentially ejects low angular momentum material because star formation is more efficient at smaller galactic radii. This results in (jgal/mgal) increasing with decreasing halo mass. This effect helps to resolve the discrepancy between the high spin parameters observed for dwarf galaxies with the low spin parameters predicted from ΛCDM . |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0810.4963v2.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/0810.4963v3.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/0810.4963v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | AngularJS Arabic numeral 0 Computer cooling Cool - action DWARF Dark Matter Discrepancy function Efficiency Environmental Wind Feedback GUCY2C protein, human Image scaling Large Small Stars, Celestial Stellar (payment network) Test scaling Tin Velocity (software development) slope |
| Content Type | Text |
| Resource Type | Article |
