Spitzer Space Telescope - General Observer Proposal #60122


A Survey for Dust in Type IIn Supernovae

Principal Investigator: Ori Fox
           Institution: University of Virginia

     Technical Contact: Ori Fox, University of Virginia

Co-Investigators: 
Michael Skrutskie, University of Virginia                             
Roger Chevalier, University of Virginia                               

Science Category: evolved stars/pn/sne 
 Observing Modes: IRAC Post-Cryo Mapping
  Hours Approved: 22.4 

Abstract:
We propose to carry out a Spitzer/IRAC mid-infrared survey for thermal dust
emission in all observable Type IIn supernovae from the past 10 years. The
source of the large amounts of dust observed in high redshift galaxies has
remained uncertain for nearly 40 years. Despite the success of models in
producing dust within supernova explosions, only a handful of supernovae show
direct observational evidence for dust condensation, and these examples all
yield 2-3 orders of magnitude less dust than predicted by the models. Recent
observations suggest Type IIn supernovae may condense more dust than typical
core-collapse events. Due to the small number of Type IIn events (2-3% of all
core-collapse supernovae), there exist too little data to draw any unbiased
conclusions concerning the nature of dust production in this particular
subclass. The few dust forming Type IIn supernovae, however, show late-time
infrared emission sometimes more than five or six years following their initial
detection, making remnant archeology possible. While previous Spitzer/IRAC
surveys have searched for dust in supernovae, none have targeted these Type IIn
events. A Spitzer/IRAC follow-up survey of all observable Type IIn supernovae
from the past ten years will determine the extent to which this subclass
produces dust. Ground-based observations are insufficient. Spitzer/IRAC provides
the necessary sensitivity at wavelengths spanning the peak of the blackbody
emission from the warmest grains, as well as the tail-end emission from colder
dust. With only 5 minutes of integration in both 3.6 and 4.5 micron bands, this
survey is sensitive to dust in almost all of our targets given our flux
estimates. In only 22.4 hours, we can obtain follow-up photometry in both bands
for all positions of observable Type IIn supernovae discovered in the past ten
years.