  We study the behavior of dust temperature and its infrared emission of
FirstLight1 simulated galaxies at the redshift of 6 and 8, by using POLARIS2 as
a Monte Carlo photon transport simulator. To calculate the dust temperature
($T_{dust}$) of the Interstellar medium (ISM) of galaxies, POLARIS requires
three essential parameters as an input - (1) The physical characteristics of
galaxies such as the spatial distribution of stars and dust, which are taken
from FirstLight galaxies. (2) The intrinsic properties of dust grains that are
derived from theDiscrete Dipole Approximation Code (DDSCAT) model. (3) The
optical properties of star-particles are in the form of their spectral energy
distributions (SEDs) which are extracted from the Binary Population and
Spectral Synthesis (BPASS) model. Our simulations produced the 3D maps of the
equilibrium dust temperature along with the sight-line infrared emission maps
of galaxies. Our results show the importance of excess heating of dust by the
Cosmic Microwave Background (CMB) radiations at high redshifts that results in
increased Mid and Far infrared (M-FIR) dust emission. The different evaluations
of dust temperature models relate diversely to the optical and intrinsic
properties of galaxies

Astrophysics of Galaxies;Computational Physics