Gas filaments of the cosmic web located around active galaxies in a proto-cluster

TL;DR

This study reports the first detection of ultraviolet Lyman-alpha emission from intergalactic gas filaments in a proto-cluster at redshift 3.1, confirming predictions of cosmic web structures fueling galaxy and black hole growth.

Contribution

It provides observational evidence of gas filaments in the cosmic web around active galaxies in a proto-cluster, previously only predicted by simulations.

Findings

Detection of Lyman-alpha emission from filaments over 1 Mpc

Filaments are associated with intense star formation and black-hole activity

Gas structures likely fuel galaxy and black hole growth in proto-clusters

Abstract

Cosmological simulations predict the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve. However, the faintness of any emission from these filaments has limited tests of this prediction. We report the detection of rest-frame ultraviolet Lyman-alpha radiation from multiple filaments extending more than one megaparsec between galaxies within the SSA 22 proto-cluster at a redshift of 3.1. Intense star formation and supermassive black-hole activity is occurring within the galaxies embedded in these structures, which are the likely sources of the elevated ionizing radiation powering the observed Lyman-alpha emission. Our observations map the gas in filamentary structures of the type thought to fuel the growth of galaxies and black holes in massive proto-clusters.