Like rivers feeding oceans, streams of gas nourish galaxies throughout the cosmos. But these streams, which make up a part of the so-called cosmic web, are very faint and hard to see. While astronomers have known about the cosmic web for decades, and even glimpsed the glow of its filaments around bright cosmic objects called quasars, they have not directly imaged the extended structures in the darkest portions of space-until now.
New results from the Keck Cosmic Web Imager, or KCWI, which was designed by Caltech's Edward C. Stone Professor of Physics Christopher Martin and his team, are the first to show direct light emitted by the largest and most hidden portion of the cosmic web: the crisscrossing wispy filaments that stretch across the darkest corners of space between galaxies. The KCWI instrument is based at the W. M. Keck Observatoryatop Maunakea in Hawaiʻi.
"We chose the name Keck Cosmic Web Imager for our instrument because we were hoping it would directly detect the cosmic web," says Martin, who is also the director of the Caltech Optical Observatories, which includes Caltech's portion of Keck; other Keck partners are the University of California and NASA. "I'm very happy it worked out."
