| Description |
We propose to use the unique power ot Herschel to analyze the most
extreme resolvable photdissociation regions, i.e. those at low metallicity
and energized by hard radiation. With a modest investment of observing
time, we will probe a unique part of parameter space, providing a strong
lever arm to test the validity of PDR models. Furthermore, the conditions
of low metallicity and hard field are exactly those which are more
prevalent in the early universe compared to today, and increasingly
important to understand the interstellar medium of early galaxies.
The regions we propose to study in detail in the local universe are a
unique window into how the first stars affected their environments,
which we will not easily study at this resolution.
The only PDRs close enough to resolve their structure and at low
metallicity are in the Magellanic Clouds. There are only a few nebulae
in the Clouds that are clearly energized by the extremely hard
radiation from Wolf-Rayet Stars, and we will analyze two in each
galaxy, which combined with our existing Spitzer and Herschel data will
provide unprecedented information on PDR physics throughout the
universe. |
