Dr. Koki Kakiichi from UCL visiting DAWN

Dr. Kakiichi will be giving a cake talk.

Radiation hydrodynamics of turbulence, jets, and winds in HII regions:
implications to reionisation-era galaxies

The question of whether massive stars in early star-forming galaxies
generate sufficient Lyman continuum (LyC) photons to drive cosmic
reionisation is one of the major challenge in modern cosmology. Recent
deep HST UV imaging and spectroscopy have revealed a signature of LyC
leakage along the lines-of-sight of Lyman-alpha emitting galaxies both
in the local (z~0) and high redshift (z~2-3) universe. The observed
correlations between LyC escape fraction, Lyman alpha line, and other
nebular lines provide a valuable insight into the massive stellar
population and ISM of reionisation-era galaxies. In order to
understand these new observational results, in this talk, we discuss
the emergent ionising and spectral properties of galaxies using the
radiation (magneto-)hydrodynamic simulations of turbulence, jets and
winds in HII regions, examining the physical origins of the
correlations between LyC leakage, HI covering fraction, kinematics,
and the emergent Lyman alpha spectra. We discuss the role of
turbulence, shocks, and radiative feedback and show that (often
unresolved) radiation hydrodynamical process through turbulent HII
regions and the ISM is key for understanding the observed LyC leakage,
Lyman alpha lines, and other UV-to-optical spectroscopic properties
seen in the recent observation.