PhD Thesis (PDF) - Department of Astronomy - University of Virginia

Fig. 1.1.— Hubble Tuning Fork, courtesy of http://hubblesite.org. Early-type galaxies,
ellipticals (Es) and lenticulars (S0s), form the base of the tuning fork.
µ is the mean particle mass in terms of the proton mass mp and σ is the stellar
velocity dispersion. SNe can also add heavy elements and heat to the gas. For a
typical early-type galaxy, Type Ia SNe may be capable of driving a galactic outflow
at current times for galaxies with shallow enough potential wells and a small amount
of interstellar gas. In the past when early-type galaxies primarily formed, they may
have had very high rates of core-collapse supernovae that expelled enriched gas from
the galaxy. In groups and clusters of galaxies, some of this gas can eventually fall
back through the deeper potential well of the local environment and return to the
galaxy. In general, the gravitational potential wells of groups and clusters are deeper
than those of galaxies, and intragroup and intracluster gas is hotter than the gas in
galaxies.
Since different SNe types have varying abundance patterns, abundance measure-
ments have the capacity to help disentangle the origin of the gas. In particular, the
radial pattern of abundance may trace the flow of hot gas.
By measuring the gas density and temperature profiles, the total mass profile
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