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Computational astrophysics
Astronomy is an area of applied physics in which unusually beautiful objects challenge the imagination to explain observed phenomena in terms of known laws of physics. It is a field that has stimulated the development of physical laws and of mathematical and computational methods. Current computational applications are discussed in terms of stellar and galactic evolution, galactic dynamics, and particle motions
The Dwarfs Beyond: The Stellar-to-Halo Mass Relation for a New Sample of Intermediate Redshift Low Mass Galaxies
A number of recent challenges to the standard Lambda-CDM paradigm relate to
discrepancies that arise in comparing the abundance and kinematics of local
dwarf galaxies with the predictions of numerical simulations. Such arguments
rely heavily on the assumption that the local dwarf and satellite galaxies form
a representative distribution in terms of their stellar-to-halo mass ratios. To
address this question, we present new, deep spectroscopy using DEIMOS on Keck
for 82 low mass (10^7-10^9 solar masses) star-forming galaxies at intermediate
redshift (z=0.2-1). For 50 percent of these we are able to determine resolved
rotation curves using nebular emission lines and thereby construct the stellar
mass Tully-Fisher relation to masses as low as 10^7 solar masses. Using scaling
relations determined from weak lensing data, we convert this to a
stellar-to-halo mass (SHM) relation for comparison with abundance matching
predictions. We find a discrepancy between the propagated predictions from
simulations compared to our observations, and suggest possible reasons for this
as well as future tests that will be more effective.Comment: 11 pages, 7 figures, submitted to ApJ, comments welcom
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