  Elliptical galaxies comprise primarily old stars, which collectively generate
a long-lasting feedback via stellar mass-loss and Type Ia SNe. This feedback
can be traced by X-ray-emitting hot gas in and around such galaxies, in which
little cool gas is typically present. However, the X-ray-inferred mass, energy,
and metal abundance of the hot gas are often found to be far less than what are
expected from the feedback, particularly in so-called low L_X/L_B ellipticals.
This "missing" stellar feedback is presumably lost in galaxy-wide outflows,
which can play an essential role in galaxy evolution (e.g., explaining the
observed color bi-modality of galaxies). We are developing a model that can be
used to properly interpret the X-ray data and to extract key information about
the dynamics of the feedback and its interplay with galactic environment.
