Spitzer Space Telescope - General Observer Proposal #20356


The Nearby and Extremely Metal-Poor Galaxy CGCG 269-049

Principal Investigator: David Burstein
           Institution: Arizona State University

Co-Investigators: 
Michael Corbin, Arizona State University                              

Science Category: nearby galaxies (z<0.05, v_sys<15,000 km/s) 
 Observing Modes: IracMap IrsMap MipsPhot 
  Hours Approved: 8.8 

Abstract:
We propose to obtain IRAC and MIPS imaging and an IRS spectral map of
the nearby (~ 2 - 3 Mpc) extremely metal-poor (12 + log(O/H) = 7.43)
blue dwarf galaxy CGCG 269-049.  This object offers an unprecendented
opportunity to study an extremely metal-poor galaxy at high spatial
resolution, as it has a major axis of approximately 40".  Spitzer data
will establish whether this object contains a large amount of dust
indicative of past episodes of star formation, which will in turn
indicate whether or not it is forming its first generation of stars.
The proposed observations will also establish whether, like some other
blue dwarf galaxies, CGCG 269-049 contains dust-obscured super star
clusters that are redistributing its flux to the mid-infrared.  The
IRS spectral map will reveal any spatial variation in the properties
of the galaxy's dust, such as temperature, grain size, and the
presence of PAHs.  This will in turn aid in the interpretation of the
mid-IR spectra of more compact blue dwarf galaxies, whose spectra
represent their spatially-integrated emission.