Spitzer Space Telescope - Guaranteed Time Observer Proposal #40349


Star Formation in Early-type Spirals

Principal Investigator: Giovanni Fazio
           Institution: Smithsonian Astrophysical Observatory

     Technical Contact: Zhong Wang, Smithsonian Astrophysical Observatory

Co-Investigators: 
Stephanie Bush, Harvard University                                    

Science Category: nearby galaxies (z<0.05, v_sys<15,000 km/s) 
 Observing Modes: IracMap MipsPhot 
  Hours Approved: 12.0 

Abstract:
Recent studies of nearby early-type (Sa-Sab) spiral galaxies have revealed a
significant fraction (~30%) which are actively forming stars. It has been
suggested that past close encounters or minor mergers may be inducing activities
in these systems, which would otherwise remain quiescent and passively evolve.
We propose to perform IRAC and MIPS observations to measure the distribution and
luminosity function of the star-forming regions in a selected sample of these
galaxies. The data, when combined with ground-based narrow-band imaging and
broad-band SED studies, can provide a definitive explanation to how star
formation is affected by interactions, and address to what extent these can be
considered as an essential part of galactic evolution.