From the July 2009 issue

Getting a kick out of merging

A simulation shows how merging galaxies can fling stars to hypervelocities.
By | Published: July 27, 2009 | Last updated on May 18, 2023
Merging galaxies simulation

When a satellite galaxy gets too close to its massive central galaxy, the large galaxy’s gravity tears apart the satellite. Some of the galaxy’s stars merge with the larger galaxy. But for others, the massive galaxy flings the stars from the satellite — some at extreme speeds. According to astrophysicists Mario G. Abadi, Julio F. Navarro, Matthias Steinmetz, and Laura V. Sales, these stars could be the hypervelocity stars that astronomers have observed.