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[11/12] LaRT (Lyman-alpha Radiative Transfer): The WF effect, LyA Emitters, and LyA Polarization
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2019.10.12
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LaRT (Lyman-alpha Radiative Transfer): The WF effect, LyA Emitters, and LyA Polarization as a probe for fundamental physics

Speaker: Dr. Kwang-Il Seon (KASI)

Date: 2019/11/12, Tuesday, 5 pm

Room: Science hall B102

Language: English


Abstract:

Lyα emission is one of the most prominent emission features in the universe. In this talk, I will introduce a three-dimensional Monte Carlo Lyα radiative transfer (RT) code, named as LaRT, which has been developed to study the Lyα RT and the Wouthuysen-Field effect. Using the code, I calculated the line profile of Lyα radiation within astrophysical gas clouds with low densities. I will show that the central portion of the line profile approaches a small slice of the Planck function with a color temperature equal to the gas kinetic temperature, even in a system with an optical depth as low as a few hundred. I will also discuss the effects of the turbulent motion of the interstellar medium (ISM) on the emergent Lyα spectrum and spin temperature. It will be presented that the turbulent motion broadens the emergent spectrum, but the spin temperature is not affected by the turbulent motion in typical astrophysical environments. The Lyα RT calculations have been also performed to understand Lyα properties of Lyα emitters at high redshifts. I will present that the models successfully reproduce both the spectra and the surface brightness profiles of eight star-forming galaxies at z =3–6 observed with MUSE using this outflowing halo model with Lyα scattering. LaRT also can deal with the Lyα polarization, using the Stokes parameters formalism, in a very natural way. I will also discuss how a joint analysis of the Lyα spectra, surface brightness profiles, and polarization will help us extract unique physical information on galaxies and their environments.

발표자
Kwang-Il Seon