NASA's Hubble Space Telescope has photographed an unusual structure 100,000 light years long, which resembles a corkscrew-shaped string of pearls and winds around the cores of two colliding galaxies.
The unique structure of the star spiral may yield new insights into the formation of stellar superclusters that result from merging galaxies and gas dynamics in this rarely seen process.
"We were surprised to find this stunning morphology. 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," said Grant Tremblay of the European Southern Observatory in Garching, Germany.
Young, blue super star clusters are evenly spaced along the chain through the galaxies at separations of 3,000 light-years. The pair of elliptical galaxies is embedded deep inside the dense galaxy cluster known as SDSS J1531+3414. The cluster's powerful gravity warps the images of background galaxies into blue streaks and arcs that give the illusion of being inside the cluster, an effect known as gravitational lensing.
Observing astronomers first hypothesized 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 in Santa Cruz de Tenerife, Spain, ruled out this hypothesis.
The galaxy cluster is part of a Hubble program to observe 23 massive clusters that create powerful gravitational lensing effects on the sky. The clusters were first cataloged in the Sloan Digital Sky Survey (SDSS), a project to create the most detailed three-dimensional maps ever made of the universe.
Tremblay's team discovered the bizarre string of stellar superclusters by chance, while reviewing images as they came in from Hubble. Researchers were stunned by what they saw in SDSS J1531+3414, and the unique nature of the source spurred the team to do follow-up observations with both ground and space-based telescopes.
The underlying physical processes that give rise to the "string of pearls" structure are related to the Jeans instability, a physics phenomenon that occurs when the internal pressure of an interstellar gas cloud is not strong enough to prevent gravitational collapse of a region filled with matter, resulting in star formation. This process is analogous to that which causes a column of water falling from a rain cloud to disrupt, and rain to fall in drops rather than in continuous streams.
Scientists currently are working on a better understanding of the star chain's origin. One possibility is that the cold molecular gas fueling the burst of star formation may have been native to the two merging galaxies. Another possibility is a so-called "cooling flow" scenario, where gas cools from the ultra-hot atmosphere of plasma that surrounds the galaxies, forming pools of cold molecular gas that starts to form stars. The third possibility is that the cold gas fueling the chain of star formation originates from a high-temperature shock wave created when the two giant elliptical galaxies crash together. This collision compresses the gas and creates a sheet of dense cooling plasma.
"Whatever the origin for this star-forming gas is, the result is awesome. It's very exciting. You can't find a mundane explanation for this," Tremblay said.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
For images and more information about Hubble, visit:
To learn more about gravitational lensing, visit:
Ray Villard | Eurek Alert!
Streamlining accelerated computing for industry
24.08.2016 | DOE/Oak Ridge National Laboratory
Lehigh engineer discovers a high-speed nano-avalanche
24.08.2016 | Lehigh University
Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...
Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.
In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...
Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.
Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...
Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...
A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.
25.08.2016 | Event News
24.08.2016 | Event News
12.08.2016 | Event News
29.08.2016 | Materials Sciences
29.08.2016 | Life Sciences
29.08.2016 | Medical Engineering