Spitzer Space Telescope - Archive Research Proposal #30836


Star Formation in the Large Magellanic Cloud

Principal Investigator: You-Hua Chu
           Institution: University of Illinois at Urbana-Champaign

Co-Investigators: 
Robert Gruendl, University of Illinois                                
Leslie Looney, University of Illinois                                 
Rosie Chen, University of Illinois                                    
Rosa Williams, University of Illinois                                 
Mordecai Mac Low, American Museum of Natural History                  
Lee Hartmann, University of Michigan                                  
Nuria Calvet, University of Michigan                                  
Wolfgang Brandner, Max Planck Institute                               
Chris Smith, CTIO                                                     
Sean Points, CTIO                                                     
John Dickel, University of New Mexico                                 

Science Category: local group galaxies 
Dollars Approved: 100000.0 

Abstract:
Star formation is fundamental to the evolution of galaxies.  It can be
simply described on global scales, but shows remarkable variation on
local scales.  Theoretical models describe numerous paths to star
formation, from global gravitational instability to local formation
dynamically triggered by cloudlet compression in superbubbles,
compression by H II region expansion, and gas accumulation in the
borders of supergiant shells.  For a better understanding of star
formation, one must empirically relate the initial level of
gravitational instability, and any triggering mechanisms, to the final
result.  The Large Magellanic Cloud (LMC) is the optimal site for such
a study, as it is close enough to resolve protostars, yet not subject
to the line-of-sight confusion of the Galaxy.  Our Cycle 1 IRAC/MIPS
observations of seven LMC HII complexes revealed a wide range of
triggered star formation phenomena.  The Spitzer survey of the LMC
(SAGE), carried out in Cycle 2, reveals massive protostars throughout
the entire LMC galaxy, allowing studies of global star formation.  We
propose to use the archival data from the Spitzer survey, and multi-
wavelength surveys of stars and ISM in the LMC, to study star
formation.  We will examine both the interstellar conditions that lead
to star formation, and the mass functions and clustering properties of
protostars that are formed.  For the former we will evaluate the
gravitational potential from the stellar and gas surface densities;
search for expanding shells that may be triggers;  and examine the
physical conditions in star formation sites.  For the latter we will
create a census of protostar candidates and their spatial
distribution.  Combined, these will allow us to determine the causes
of star formation and how these affect the mass function and
clustering properties of the stars formed.