Speaker
Description
The Lyman-alpha (Lya) emission line is a powerful tool for studying the circumgalactic medium (CGM) of high redshift galaxies. Large-scale gas flows induced by feedback as well as accretion, mediated by resonant scattering at HI gas, imprint themselves through the skewed spectral shape of the line and the frequent presence of two distinct peaks. Recent obervations revealed for the first time a trend at large radii (r >~ 15 kpc, or ~0.5 R_vir) that the "red peak" of the line shifts back towards systemic and even beyond - a trend not previously predicted by models. This phenomenon could mark the importance of inflows to shape the outer CGM of high-z galaxies, competing with the strong outflows that presumably dominate the inner circumgalactic regions. Here we present the first analysis of this phenomenon for a large sample of Lya emitters using exquisit observing data with MUSE obtained in various Deep Fields. We quantify the Lya profile evolution out to very large radii, in particular the peak shift behaviour, and link this to the kinematics of the underlying gas flows.
