Hot Dust in Galaxies at 0.25 < z < 0.29
Date
2022-07-01
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Abstract
Thermal dust emission within galaxies is driven by heating from young, hot stars. Because
of this, one way to examine star formation in a galaxy is through the distribution of starlight
and hot dust light. Independent component analysis (ICA) is a method of separating each
source in a mixed signal by maximizing each signal’s negentropy. Negentropy is the opposite
of entropy, which is a measure of the disorder in a system, so the sources are separated by
maximizing their order. ICA can be used to separate starlight and hot dust light within
galaxies, and has been used previously to calculate total stellar masses and study star for-
mation in galaxies at z 0. This thesis applies this method to characterize the distribution of
starlight and dust light in galaxies at 0.25 ≤ z ≤ 0.29 and calculate their total stellar masses.
The results in this thesis show that star formation in the target galaxies is primarily
on the outermost edges of the galaxies, potentially indicating an inside-out star formation
history. Additionally, the results presented here show that star formation decreases with
increasing total stellar mass. Galaxies in this range of redshifts emitted the light observed
about 3 billion years ago, so these results provide insight into how galaxies have changed
since this era.
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Keywords
astronomy, astrophysics, galaxies, dust