Spitzer Space Telescope - General Observer Proposal #3333


Supernovae and the Origin of Dust in Galaxies

Principal Investigator: Michael Barlow
           Institution: University College London

Co-Investigators: 
Janet Bowey, University College London                                
Geoffrey Clayton, Louisiana State University                          
Martin Cohen, University of California, Berkeley                      
Ethan Deneault, Clemson University                                    
Joanna Fabbri, University College London                              
Tim Gledhill, University of Hertfordshire                             
Karl Gordon, Steward Observatory, University of Arizona               
Margaret Meixner, Space Telescope Science Institute                   
Nino Panagia, Space Telescope Science Institute                       
Angela Speck, University of Missouri                                  
Ben Sugerman, Space Telescope Science Institute                       
Alexander Tielens, University of Groningen                            
Douglas Welch, McMaster University                                    
Michael Wolff, Space Science Institute, University of Colorado        
Albert Zijlstra, UMIST, Manchester                                    

Science Category: nearby galaxies (z<0.05, v_sys<15,000 km/s) 
 Observing Modes: IracMap MipsPhot 
  Hours Approved: 9.3 

Abstract:
We propose to use IRAC and MIPS to carry out a sensitive mid-IR survey
for thermal dust emission from 30  nearby extragalactic supernovae
(SNe) discovered between April 1999 and January 2004.  The goal is to
find evidence for dust formation and spectral evolution in the SN
ejecta and to determine the masses of dust that have been formed, in
order to quantify for the first time the contribution by SNe to the
dust cycle of galaxies.  Our estimates for the mid-IR brightnesses of
our targets are conservatively based upon SN 1987A, which formed
modest amounts of dust and whose emission peaked in the mid-IR.  For
each target we will use an IRAC AOR of 1574s, yielding 600s per pixel
in all four bands, together with a MIPS 24-micron AOR of 2639s,
yielding an exposure time per pixel of 2*1088s.  The IRAC and MIPS
observations will yield comparable image fov's of 5x5 arcmin.  The
IRAC observations are capable of detecting SN1987A-type events between
3.6 and 8.0  microns to distances of up to 25 Mpc, while the MIPS
observations could detect SN 1987A at 24 microns out to distances of
15 Mpc.  The 30  SNe that have been selected have distances of less
than 25 Mpc and consist of 23 massive-star SNe (16 Type II, 7 Type
Ib/c) and 7 low-mass Type Ia SNe.  The 28 IRAC and MIPS fields needed
to cover the 30  SNe require a total of 32.8 hours of observing time.
Our team comprises experienced IR observers, together with experts on
supernovae, dust grain characteristics, and mass loss from evolved
stars, The team members have extensive accumulated experience in the
analysis of thermal IR spectra to derive the properties and masses of
emitting dust and have available to them several state-of-the-art dust
radiative transfer codes, including ones developed by members of the
team.  We have an approved high-priority 2004/5 8-m Gemini programme,
to obtain high angular resolution mid-IR imaging of recent SNe, which
will enhance and complement the current proposal.