Speaker: Jorryt Matthee (ETH)
Title: Characterising Lyman-alpha emitting galaxies from the epoch of reionisation to cosmic noon
Abstract:
The bright Lyman-α (Lyα) line is a key observable in studies of galaxies in the early Universe. Lyα emitters (LAEs) are likely galaxies that are in the very first stages of their formation. However empirically, their detailed properties remain poorly understood. In my talk I will present recent observational results to characterise the properties of stars and gas in such young galaxies in the first 3 Gyrs. I will also exploit the detailed shape and strength of the Lyα emission line to study the neutral gas structure and content in and around these galaxies. I will first present results of the new ‘XLS-z2’ survey which is based on ~100 hours of VLT/X-SHOOTER observations of 30 LAEs at z~2. At this redshift we can already measure the various properties of the interstellar medium (ISM) and stellar populations that for most galaxies require future observations with the James Webb Space Telescope (JWST). I will focus in particular on the diversity among the Lyα line profiles emerging from the ISM and what these tell us about the ionising escape fraction and therefore the role of galaxies in driving reionisation. In addition, I will also present highlights from detailed follow-up of bright star-forming galaxies at the end of reionisation with VLT/MUSE, ALMA and HST observations, including the discovery of of a galaxy hosting an ionised bubble at z=6.6 (that it may have caused itself), the detection of gas feeding the young starburst in a triple merger and the first measurements of the age and metallicities from detailed wind features of massive stars in a galaxy at redshift z~5.