  Narrow-band Lya line and broad-band continuum have played important roles in
the discovery of high-redshift galaxies in recent years. Hence, it is crucial
to study the radiative transfer of both Lya and continuum photons in the
context of galaxy formation and evolution in order to understand the nature of
distant galaxies. Here, we present a three-dimensional Monte Carlo radiative
transfer code, All-wavelength Radiative Transfer with Adaptive Refinement Tree
(ART^2), which couples Lya line and multi-wavelength continuum, for the study
of panchromatic properties of galaxies and interstellar medium. This code is
based on the original version of Li et al., and features three essential
modules: continuum emission from X-ray to radio, Lya emission from both
recombination and collisional excitation, and ionization of neutral hydrogen.
The coupling of these three modules, together with an adaptive refinement grid,
enables a self-consistent and accurate calculation of the Lya properties. As an
example, we apply ART^2 to a cosmological simulation that includes both star
formation and black hole growth, and study in detail a sample of massive
galaxies at redshifts z=3.1 - 10.2. We find that these galaxies are Lya
emitters (LAEs), whose Lya emission traces the dense gas region, and that their
Lya lines show a shape characteristic of gas inflow. Furthermore, the Lya
properties, including photon escape fraction, emergent luminosity, and
equivalent width, change with time and environment. Our results suggest that
LAEs evolve with redshift, and that early LAEs such as the most distant one
detected at z ~ 8.6 may be dwarf galaxies with a high star formation rate
fueled by infall of cold gas, and a low Lya escape fraction.
