Spitzer Space Telescope - Theoretical Research Proposal #50387


Infrared Properties of High-z Galaxies

Principal Investigator: Kentaro Nagamine
           Institution: University of Nevada, Las Vegas

     Technical Contact: Kentaro Nagamine, University of Nevada, Las Vegas

Science Category: high-z galaxies (z>0.5) 
Dollars Approved: 50000 

Abstract:
We propose to compute the SEDs of high-redshift galaxies in cosmological
hydrodynamic simulations using the spectrophotometric code GRASIL (Silva et al.
1998) with the wavelength coverage from 100 angstroms to 1 meter. The proposed
method will improve the earlier work in the treatment of infrared (IR) emission
from dust in high-z star-forming galaxies, by performing the calculation in a
more ab initio fashion. Based on the computed SEDs and magnitudes in IRAC/MIPS
bands, we will generate the light-cone output of galaxies by stitching numerous
simulation output, and examine the number counts, redshift distribution,
luminosity functions (LFs) and color-color diagrams by comparing with the
Spitzer results directly. In particular, we will assess the validity of the
recent claim by Lacey et al. that a top-heavy IMF is necessary to explain the
strong evolution of mid-IR LF at 0<z<2 observed by the Spitzer. The clustering
of IR galaxies at 0<z<2 will also be computed and compared with the SWIRE
results. Finally we will study the IR properties of massive galaxies at z~6 that
were identified by the Spitzer IRAC observations. Our work will provide testable
theoretical framework to interpret rich observational datasets provided by
Spitzer, and improve physical understanding of galaxy formation and evolution.