ESA's Planck Space Telescope Spots Hot Gas Bridge Connecting Galaxy Clusters

Posted on November 21, 2012

Abell Hot Gas Bridge

Astronomers using ESA's Planck space telescope have made the first conclusive detection of a bridge of hot gas connecting a pair of galaxy cluster. The hot gas bridge connects the Abell 399 and Abell 401 clusters across 10 million light-years of intergalactic space.

Jan Tauber, Planck project scientist at ESA, said in a release, "This discovery highlights the ability of Planck to probe galaxy clusters out to their outskirts and even beyond, allowing us to investigate the connection between intra-cluster gas and gas that is part of the cosmic web."

Jose M. Diego, a Planck Collaboration scientist from the Instituto de Fisica de Cantabria (UC-CSIC) in Santander, Spain, says, "Planck can detect galaxy clusters across the sky because the hot gas that fills them imprints a characteristic signature on the Cosmic Microwave Background known as the Sunyaev-Zel'dovich effect. Based on the same principle, Planck could be sensitive to gas from the WHIM, too."

The WHIM stands for warm-hot intergalactic medium. The ESA scientists say the WHIM is the "baryonic component of the cosmic web, a filamentary network of both dark and baryonic matter that is believed to pervade the Universe."

Image: Sunyaev-Zel'dovich effect (orange): ESA & Planck Collaboration; optical image: STScI Digitized Sky Survey