Spitzer Space Telescope - General Observer Proposal #30491


A Complete Picture of the Dust in the Small Magellanic Cloud:
Following up Spitzer Imaging with Spectroscopic Observations

Principal Investigator: Alberto Bolatto
           Institution: University of California at Berkeley

Co-Investigators: 
Snezana Stanimirovic, U.C. Berkeley                                   
Karin Sandstrom, U.C. Berkeley                                        
Joshua Simon, Caltech                                                 
J.D. Smith, U. of Arizona                                             
James Ingalls, IPAC                                                   
Bruce Draine, Princeton University                                    
Aigen Li, University of Missouri-Columbia                             
Frank Israel, University of Leiden                                    
Francois Boulanger, Institute d'Astrophysique Spatiale                
James Jackson, Boston University                                      
Jacco van Loon, Keele University                                      
Monica Rubio, Universidad Nacional de Chile                           
Adam Leroy, U.C. Berkeley                                             
Ronak Shah, Boston University                                         
Caroline Bot, IPAC                                                    

Science Category: local group galaxies 
 Observing Modes: IrsMap IrsStare 
  Hours Approved: 105.6 

Abstract:
We request Spitzer Space Telescope time to obtain wide-field
spectroscopic maps of several regions in the Small Magellanic Cloud.
This survey is complementary to the imaging information obtained by
the Spitzer survey of the SMC (S3MC), and it is designed to sample a
variety of environments.  We will use these data to unravel the
life-cycle, distribution, abundance, and composition of PAHs and dust
throughout the SMC, linking spectral variations to the measured
IRAC/MIPS SEDs.  IRS spectroscopy will allow us to relate variations
in PAH and dust chemistry and excitation (such as size, structure,
hydrogenation, and ionization state) to the physical conditions and
astrophysical processes present in the mapped regions.  This study
will provide strong constraints on theoretical dust models, in
addition to producing information on the abundance, life cycle, and
evolution of PAHs and VSGs.  Ultimately, this research will help
constrain the properties of the ISM in primordial galaxies at high
redshifts.This project takes advantage of the uniquely new ability of
Spitzer, which is capable of obtaining sensitive spectral maps
covering large areas with a modest investment of time.