Astronomers have found evidence that an enormous explosion billions of years ago may explain the formation of a striking pattern of star clusters around two massive galaxies — resembling “beads on a string” — in a galaxy cluster. These images show SDSS J1531 in X-rays from Chandra, radio data from LOFAR and optical data from Hubble. The Chandra data reveal wing shaped X-ray emission that traces dense gas near the center of SDSS J1531. These wings are the edge of a cavity created by a jet from a supermassive black hole pushing gas aside. LOFAR shows radio waves from the remains of the jet’s energetic particles filling in the giant cavity. Together, these data provide compelling signs of an ancient, massive explosion.

This tactile plate is a physical relief map based on the intensity of X-ray, Radio and Optical data, depicting a string of star clusters resembling beads on a string in the galaxy cluster SDSS J1531. The plate features a central raised cloud representing X-rays from hot gas observed by Chandra, other less prominent clouds representing radio data, and raised dots, curved lines in ridges showing optical data.

The central cloud spreads out for thousands of light-years toward the region above the central galaxies. The less raised area, somewhat resembling the shape of an upside down spinning top toy, stretches far below the two galaxies and slightly toward our left. This cloud represents the remains of a powerful jet, produced by a supermassive black hole within one of the two central galaxies. In the upper right corner of the image, another slightly raised radio cloud is present. This cloud may be the relic of a counter-jet from the same black hole outburst.