| Names |
Gail Zasowski, S. R. Majewski, R. A. Benjamin, D. L. Nidever, M. F. Skrutskie, R. Indebetouw, R. J. Patterson, M. R. Meade, B. A. Whitney, B. Babler, E. Churchwell, C. Watson |
| Abstract |
The primary laboratory for developing and testing models of galaxy
formation, structure, and evolution is our own Milky Way, the closest
large galaxy and the only one in which we can resolve large numbers of
individual stars. The recent availability of extensive stellar surveys,
particularly infrared ones, has enabled precise, contiguous measurement
of large-scale Galactic properties, a major improvement over inferences
based on selected, but scattered, sightlines. However, our ability to
fully exploit the Milky Way as a galactic laboratory is severely
hampered by the fact that its midplane and central bulge -- where most
of the Galactic stellar mass lies -- is heavily obscured by interstellar
dust. Therefore, proper consideration of the interstellar extinction is
crucial. This thesis describes a new extinction-correction method (the
RJCE method) that measures the foreground extinction towards each star
and, in many cases, enables recovery of its intrinsic stellar type. We
have demonstrated the RJCE Method's validity and used it to produce new,
reliable extinction maps of the heavily-reddened Galactic midplane.
Taking advantage of the recovered stellar type information, we have
generated maps probing the extinction at different heliocentric
distances, thus yielding information on the elusive three-dimensional
distribution of the interstellar dust. We also performed a study of the
interstellar extinction law itself which revealed variations previously
undetected in the diffuse ISM and established constraints on models of
ISM grain formation and evolution. Furthermore, we undertook a study of
large-scale stellar structure in the inner Galaxy -- the bar(s),
bulge(s), and inner spiral arms. We used observed and
extinction-corrected infrared photometry to map the coherent stellar
features in these heavily-obscured parts of the Galaxy, placing
constraints on models of the central stellar mass distribution. |