. Galaxies which have stopped producing stars long ago can be brought back to life by merging clusters of galaxies. The shock waves created when these galaxies come together (sometimes referred to simply as cosmic tsunamis) can cause the birth of new stars. Leiden Observatory’s Andra Strae and David Sobra of the University of Lisbon led an international research team. (citations below). The galaxy clusters look a lot like large cities. They are densely packed with thousands of galaxies, at least when compared to the space surrounding them. Composite image of the CIZA J 2242.8 merging cluster CIZA J , made with data from Subaru and Canada France Hawaii Telescopes. Credit: Andra Strae. Galaxy clusters are similar to cities that absorb their neighbours as they grow. Over billions of years, they build up structures in the universe as they combine with other clusters. Massive amounts of energy are released when clusters merge. This shock wave causes a tsunami effect in the clusters and creates a huge energy release. There was no evidence to suggest that galaxies were affected by the shock wave. Stroe and Sobral observed the merger galaxy cluster CIZA 2242.8 +5301,, dubbed the “Sausage”, which is located at 2.3 billion miles from Earth, heading in the direction the constellation Lacerta in the sky’s north hemisphere. Astronomers employed the William Herschel, Isaac Newton Telescopes at La Palma and the CFHT and Subaru Telescopes in Hawaii to observe the merging galaxy cluster CIZA J2242.8+5301, which is located 2.3 billion light years from Earth. They discovered that the shock wave had transformed the galaxies of the cluster, sparking the formation a new type of star. Stroe: Comatose galaxies are brought back to life Stroe stated that they assumed the galaxies would play a supporting role in this event. Star formation is accelerating at incredible rates thanks to the Sausage galaxy’s comatose galactic cluster. We were stunned when we saw it in the data for the first time. Stroe said that the shocks cause turbulence to the galactic gases, much like when you stir a cup of coffee with a teaspoon. The shocks cause an avalanche-like collapsing, which ultimately leads to formation of extremely dense, cold gases clouds. These are crucial for the formation new stars. These explosions push huge quantities of gas from the galaxies, and most of it is consumed by star formation. The galaxies quickly run out of fuel. A radio image showing the cosmic tsunami in the ‘Sausage” merging cluster. Credit: Andra Strae. “Cluster mergers can make galaxies more reddened and dead. They slip back into a state of unconsciousness and are unlikely to recover.” Every galaxy cluster in the Universe has been through a number of mergers over its life. They should have all been through periods of star formation. A brief increase (astronomically speaking), in star formation can be caused by shocks. To be able catch the cluster during it’s evolution, when its galaxies still are being “lit up” by the tsunami, astronomers will need to have some luck. Scientists now want to determine if the Sausage phenomenon is unusual and if star formation bursts require very specific conditions. By studying more galaxies, they hope to discover how these phenomena occur. Citations: 1. Citations: 1. A. Rottgering. Monthly Notices of The Royal Astronomical Society. 23 April. 2015. DOI: 10.1093/mnras/stu2519. 2. “MC2″: boosted AGN activity and star formation activity within CIZA J 8 +5301, a large post-merger cluster with z = 0. 19,” David Sobral and Andra Stroe. Also, William A. Dawson. David Wittman. M. James Jee. Huub Rottgering. Reinout J. van Weren. Marcus Bruggen. Monthly Notices of Royal Astronomical Society. 23 April. 2015. DOI: 10. 1093/mnras/stv521.
Scientists discovered that cosmic tsunamis are capable of bringing back’red-and-dead’ galaxies
