Bridge of stars links two galaxies in Abell 3667

A million-light-year stellar bridge reveals a dramatic merger between two giant galaxies in the Abell 3667 cluster.

Bridge of stars links two galaxies in Abell 3667

Astronomers have captured the first optical evidence of a bridge of stars stretching about a million light-years between two galaxies in the Abell 3667 cluster. The glow connects the lenticular galaxy IC 4965 and the jellyfish galaxy JO171 as they plunge into the cluster, its stars pulled free by immense gravity. The discovery comes from deep images taken with the Dark Energy Camera on the Victor M Blanco Telescope in Chile, compiled from 28 hours of observations over several years.

This deep optical view confirms a rapid merger of the cluster components and offers a new way to map dark matter. Intracluster light, the faint glow left behind by stripped stars, tends to follow dark matter, giving scientists an indirect handle on the unseen mass shaping these collisions. The finding also signals what the Vera C Rubin Observatory will enable with the Legacy Survey of Space and Time, a decade of southern-sky imaging that could uncover hundreds more bridges like this.

The result shows how patient data work changes what we can see. Stacking observations from multiple eras turns faint features into solid discoveries and challenges the old idea that only bright galaxies matter in cosmic dramas. It also frames intracluster light as more than a pretty afterimage; it becomes a diagnostic tool for the distribution of mass in gravity-dominated environments.

As new tools enter service, the field moves from isolated snapshots to a growing map of how matter moves during mergers. Rubin Observatory will push this map to many more systems, potentially rewriting how we understand the growth of galaxy clusters and the role of dark matter in shaping large-scale structure.

Highlights

The universe keeps its tempo while our instruments grow sharper.