Spitzer Space Telescope - Snapshot Proposal #80089


Deep IRAC1,2 Imaging of the Extended Tidal Debris Fields for the Complete GOALS
Sample of LIRGs (Part 2)

Principal Investigator: David Sanders
           Institution: Insitute for Astronomy, University of Hawaii

     Technical Contact: Jason Surace, Spitzer Science Center

Co-Investigators: 
Lee Armus, Spitzer Science Center                                     
Josh Barnes, IfA, University of Hawaii                                
Ben Chan, IPAC                                                        
Aaron Evans, University of Virginia / NRAO                            
David Frayer, NRAO                                                    
Justin Howell, Spitzer Science Center                                 
Lisa Kewley, IfA, University of Hawaii                                
Jin Koda, SUNY Stony Brook                                            
Steve Lord, IPAC                                                      
Joseph Mazzarella, IPAC                                               
Jason Surace, Spitzer Science Center                                  
Vivian U, Harvard-Smithsonian CfA / IfA, University of Hawai          

Science Category: ULIRGS/LIRGS/HLIRGS 
  Hours Approved: 106.1 

Abstract:
We propose to obtain IRAC1,2 observations (~1400 sec) to complete our
flux-limited sample of luminous infrared galaxies (LIRGs), selected from the
IRAS Revised Bright Galaxy Survey, in order to measure the full extent and
internal structure of the large tidal debris fields that have recently been
revealed (~70-130 kpc diameter) in deep optical imaging of these objects using
the Subaru 8m Telescope on Mauna Kea. Our 115 targets represent the lower
luminosity objects in the Great Observatories All-Sky LIRGs Survey (GOALS),
defining the important transition region between LIRGs and ULIRGs, for which we
are obtaining both spacecraft and ground-based data at a wide range of
wavelengths (radio thru X-Rays). All of our targets have previous shallow (~150
sec) IRAC observations, which are insufficient for detecting all but the
brightest, and much less extended tidal features. Our deeper IRAC observations
will allow us to fully characterize the history, geometry and morphology of the
interaction (major and minor mergers) for comparison with new sets of model
calculations using "IDENTIKIT" (Barnes & Hibbard, 2009). We also plan to combine
our new IRAC1,2 data with deep optical (Subaru and VLT) and NIR (HST-NIC, -WFC3)
data to determine spectral energy distributions, and to measure stellar masses
as well as detect warm dust in these extended features. These new data will also
allow us for the first time to obtain a clearer picture of the possible
interrelation of nearby objects (e.g. putative tidal dwarf galaxies, other
disconnected debris arms, shells, etc.) to the merger history of our complete
sample of local (U)LIRGs.