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Gas filaments of the cosmic web located around active galaxies in a protocluster

Umehata, H.; Fumagalli, M.; Smail, I.; Matsuda, Y.; Swinbank, A.M.; Cantalupo, S.; Sykes, C.; Ivison, R.J.; Steidel, C.C.; Shapley, A.E.; Vernet, J.; Yamada, T.; Tamura, Y.; Kubo, M.; Nakanishi, K.; Kajisawa, M.; Hatsukade, B.; Kohno, K.

Gas filaments of the cosmic web located around active galaxies in a protocluster Thumbnail


H. Umehata

Y. Matsuda

S. Cantalupo

R.J. Ivison

C.C. Steidel

A.E. Shapley

J. Vernet

T. Yamada

Y. Tamura

M. Kubo

K. Nakanishi

M. Kajisawa

B. Hatsukade

K. Kohno


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.


Umehata, H., Fumagalli, M., Smail, I., Matsuda, Y., Swinbank, A., Cantalupo, S., …Kohno, K. (2019). Gas filaments of the cosmic web located around active galaxies in a protocluster. Science, 366(6461), 97-100.

Journal Article Type Article
Acceptance Date Sep 2, 2019
Online Publication Date Oct 4, 2019
Publication Date Oct 4, 2019
Deposit Date Oct 16, 2019
Publicly Available Date Oct 16, 2019
Journal Science
Print ISSN 0036-8075
Electronic ISSN 1095-9203
Publisher American Association for the Advancement of Science
Peer Reviewed Peer Reviewed
Volume 366
Issue 6461
Pages 97-100


Accepted Journal Article (2.3 Mb)

Copyright Statement
This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science, Volume 366 October 2019, DOI: 10.1126/science.aaw5949.

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