Observations of Lyman Continuum Escape: Challenges and Future Prospects

Wednesday, 25 September 2019 9 a.m. — 10 a.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
ROB BASSETT (Swinburne University of Technology and Gemini South Visiting Astronomer)

While the overall timeline of cosmic reionization continues to be better constrained, a similar level of understanding of the sources responsible for this process remains elusive. The current paradigm strongly favours star-forming galaxies over AGN as the culprit given the significant drop in volume density of AGN at z > 5. A key parameter to measure from high redshift star-forming galaxies in order to connect them to the process of reionization is the escape fraction of hydrogen ionizing, or Lyman continuum (LyC), photons. Measurements of LyC are extremely difficult at z = 3-4 and impossible at higher redshifts due to the increasing opacity of the IGM, however. In this talk I will discuss the current state of LyC escape science, highlighting the difficulties due to IGM opacity and HII region geometry as well as on going efforts to better constrain LyC escape combining simulations, models, and observations.