Emission features formed through Raman scattering with atomic hydrogen provide unique and crucial information to probe the distribution and kinematics of a thick neutral region illuminated by a strong far-ultraviolet radiation source. We introduce a new 3-dimensional Monte-Carlo code in order to describe the radiative transfer of line photons that are subject to Raman and Rayleigh scattering with atomic hydrogen. In our Sejong Radiative Transfer through Raman and Rayleigh Scattering (STaRS) code, the position, direction, wavelength, and polarization of each photon is traced until escape. The thick neutral scattering region is divided into multiple cells with each cell being characterized by its velocity and density, which ensures exibility of the code in analyzing Raman-scattered features formed in a neutral region with complicated kinematics and density distribution. To test the code, we revisit the formation of Balmer wings through Raman scattering of the far-UV continuum near Lyβ and Lyγ in a static neutral region. An additional check is made to investigate Raman scattering of Ovi in an expanding neutral medium. We find a good agreement of our results with previous works, demonstrating the capability of dealing with radiative transfer modeling that can be applied to spectropolarimetric imaging observations of various objects including symbiotic stars, young planetary nebulae, and active galactic nuclei.

Abstract
1. INTRODUCTION
2. GRID BASED MONTE CARLO SIMULATION
    2.1. Geometry: Scattering Region
    2.2. Emission Source: Initial Photon
    2.3. Journey of a Photon: Optical Depth and Free Path
3. CODE TEST
    3.1. Formation of Balmer Wings in a Static SphericalHI Region
    3.2. Raman Scattering of OVI in Expanding HI Region
4. SUMMARY
REFERENCES

• Seok-Jun Chang(Department of Physics and Astronomy, Sejong University/Korea Astronomy and Space Science Institute)
• Hee-Won Lee(Department of Physics and Astronomy, Sejong University)