Chandra Catches Extraordinary “Slingshot” During Titanic Space Collision

Galaxy Cluster Abell 1775

These images of the galaxy cluster Abell 1775 show X-rays from Chandra, optical data from the Pan-STARRS telescope in Hawaii, and radio data from the LOw Frequency ARray (LOFAR) in the Netherlands. A tail from the merged cluster is seen, along with a region of gas with a curved edge, called a “cold front”, that is denser and cooler than the gas it is plowing into (see labeled version). The tail and the cold front all curve in the same direction, creating a spiral appearance. These features are the result of two galaxy clusters — the largest structures held together by gravity — crashing into one another, one of the most energetic events in the Universe. Credit: X-ray: NASA/CXC/Leiden Univ./A. Botteon et al.; Radio: LOFAR/ASTRON; Optical/IR:PanSTARRS

  • Abell 1775 is a system where a smaller galaxy cluster has plowed into a larger one.
  • Using X-rays from Chandra and data from other telescopes astronomers are piecing together details of this collision.
  • Features in the data, including a curving tail of hot gas and a “cold front,” are clues.
  • Scientists will likely need more observations and modeling to get the full picture of Abell 1775.

When the titans of space — galaxy clusters — collide, extraordinary things can happen. A new study using

Galaxy Cluster Abell 1775 Labeled

Labeled Multiwavelength Image of Abell 1775. Credit: X-ray: NASA/CXC/Leiden Univ./A. Botteon et al.; Radio: LOFAR/ASTRON; Optical/IR:PanSTARRS

Astronomers previously found that Abell 1775 contains an enormous jet and radio source, which is also seen in this new composite image. This jet is powered by a supermassive

The Botteon team favors the slingshot tail scenario, but a separate group of astronomers led by Dan Hu of Shanghai Jiao Tong University in China favors the sloshing explanation based on data from Chandra and ESA’s XMM-Newton. Both the slingshot and sloshing scenarios involve a collision between two galaxy clusters. Eventually, the two clusters will fully merge with each other to form a single, larger galaxy cluster.

Further observations and modeling of Abell 1775 are required to help decide between these two scenarios.

A paper describing the results by Botteon’s team has been published in the journal Astronomy and Astrophysics. The separate work on the “sloshing” theory led by Dan Hu has been accepted for publication in The Astrophysical Journal.

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.