Hubble spots ‘string of pearls’ linking two massive colliding galaxies
The astronomers’ first hypothesis was that the ‘string of pearls” was actually a lensed image from one of these background galaxies, but their recent follow-up observations with the Nordic Optical Telescope definitively rules this out.
‘We were stunned by what we saw in SDSS J1531+3414,’ Tremblay said.
‘The uniqueness of this source spurred follow-up observations with both ground- and space-based telescopes.
‘This is a beautiful demonstration of the profound scale-invariance of the fundamental laws of nature,’ Tremblay added.
The underlying physical processes that give rise to the “beads on a string” morphology are related to the Jeans instability, describing the behavior of self-gravitating clumps of gas.
It’s analogous to the process that causes a falling column of water to disrupt, explaining why rain falls in drops rather than in continuous filaments from clouds.
Water coming out of the kitchen tap eventually breaks into a series of droplets, and a very similar process is happening in SDSS J1531+3414.
‘We see the same physics on 100,000-light-year scales that we see in our kitchen sinks and inkjet printers,’ said Tremblay.
‘We’ve long known that the ‘beads on a string’ phenomenon is seen in the arms of spiral galaxies and in tidal bridges between interacting galaxies.
‘However, this particular supercluster arrangement has never been seen before in giant merging elliptical galaxies,’ he said.
‘We have two monsters playing tug-of-war with a necklace, and its ultimate fate is an interesting question in the context of the formation of stellar superclusters and the merger-driven growth of a galaxy’s stellar component.’
The Slinky-structure’s unique morphology may yield new insights into the formation of stellar superclusters, the merger-driven growth of galaxies, and gas dynamics in the rarely seen merger process of two giant elliptical galaxies.
Like a string of pearls, these young, blue ‘super star clusters’ are evenly spaced along the chain at separations of 3,000 light-years from one another.
The pair of elliptical galaxies is embedded deep inside the dense galaxy cluster SDSS J1531+3414.
The cluster’s powerful gravity warps the image of background galaxies into blue streaks and arcs that give the illusion of being inside the cluster.