Herschel Space Observatory - Theoretical Research Proposal #1024

Modeling Galactic Nuclei from the Milky Way to Starburst Galaxies

Principal Investigator: Mark Wolfire   
           Institution: University of Maryland

Co-Investigators:
Andrew Harris, University of Maryland
Michael Kaufman, San Jose State Univ


Dollars Approved: 160741

Abstract:
Several Herschel Key programs are specifically designed
to observed the infrared line emission from galactic nuclei.
These observations provide the key cooling lines
in CII, OI, and CI, required to trace the dominant gas heating
and cooling processes in neutral gas.  In addition Herschel will
observe NII  which tracks the ionized gas, upper level transitions of CO which trace
the warm molecular gas, lower level transitions of H_2O which are sensitive
diagnostics of local temperature and density, and key molecules in the
Nitrogen chemical network (NH, NH_2, and NH_3).
Galactic nuclei harbor a range of extreme environments
which are not found in the outer portions of
galaxies. In this theoretical program we will modify existing
infrared-line emission codes to account for the environments found in galactic
nuclei. In particular we will account for
large-line widths, hard radiation fields, and both high
and low metallicities. In addition we will add Nitrogen chemistry
to our code in order to calculate the column densities and line
intensities of NH, NH_2, and NH_3. The models will allow Herschel
observers to analyze their data sets with a goal towards
understanding the cloud physical conditions which drives
star formation, determine the energy budget of galactic
nuclei, and compare physical conditions in normal, and
starburst galaxies.