Spitzer Space Telescope - Archive Research Proposal #40008


Constraints on the stellar initial mass function from Spitzer

Principal Investigator: August Muench
           Institution: Smithsonian Astrophysical Observatory

     Technical Contact: August Muench, Smithsonian Astrophysical Observatory

Co-Investigators: 
Kevin Luhman, The Pennsylvania State University                       

Science Category: star formation 
Dollars Approved: 106363 

Abstract:
The stellar initial mass function (IMF) is a fundamental quantity in
astrophysics and a valuable probe of the process of star formation. While there
are many theories committed to deducing the origin of the IMF, there is also a
dearth of good IMF constraints in star forming regions and a limited range of
physical environments for which IMFs have been derived. We propose to use the
Spitzer archive to rectify this problem by deriving IMF constraints in star
forming regions over the local 1 kpc. We will construct and analyze 3 micron
luminosity functions for embedded clusters that are located in five different
star forming regions and that contain a range of most massive member stars. We
will use our existing luminosity function modeling code to constrain the basic
IMF parameters, e.g., the peak or characteristic mass formed in a star forming
region and correlate these quantities to physical environmental parameters such
as the presence of O type stars and the stellar surface density in each cluster.
The very large mosaics provided by the Spitzer archive will also allow us to
search for spatial variations of the IMF within a star cluster, variations that
we have documented using both luminosity function modeling and spectroscopic
followup.