Science Highlight - Starbursts growing in a cosmic web filament

ALMA has uncovered a huge number of dusty star-forming galaxies in the early universe. Meanwhile, what triggers and sustains intense star-forming activity seen in such star-bursting galaxies has been still unclear. In a recent Science paper, Hideki Umehata and his collaborators make use of ALMA band 3 and band 6 to identify an extremely rich cluster of star-bursting galaxies in the SSA22 proto-cluster core at z=3.1. In conjunction with deep and co-spatial MUSE mosaics, they find that all of the starbursts are embedded in a huge Lyman-alpha filament on a >1 physical Mpc scale at the proto-cluster center. The filaments of cosmic web harbor a significant reservoir of gas, which would contribute to the growth of the galaxies.