Spatially-resolved Spectroscopic Analysis of Ly$\alpha$ Haloes: Radial Evolution of the Ly$\alpha$ Line Profile out to 60 kpc

Understand

The extended Ly$\alpha$ haloes (LAHs) have been found to be prevalent around high-redshift star-forming galaxies.

• However, the origin of the LAHs is still a subject of debate.
• Spatially resolved analysis of Ly$\alpha$ profiles provides an important diagnostic.
• We analyse the average spatial extent and spectral variation of the circumgalactic LAHs by stacking a sample of 155 Ly$\alpha$ emitters (LAEs) at redshift $3<z<4$ in the MUSE Extremely Deep Field.