Royal Observatory – Death of galaxies can be forecast far in advance by observing their telltale sign when they have finished producing new stars. According to a report, what follows is a sluggish death precipitated by the materials produced during the star formation process which actually strangulates or suffocates the galaxy and lead to a slow death in approx 4 billion years.

The study which was pioneered by Researchers from the University of Cambridge and the Institute for Astronomy, Royal Observatory was published in Nature.

Study lead author Yingjie Peng, of Cambridge’s Cavendish Laboratory and Kavli Institute of Cosmology, said in a press release, “Metals are a powerful tracer of the history of star formation: the more stars that are formed by a galaxy, the more metal content you’ll see. So looking at levels of metals in dead galaxies should be able to tell us how they died.”

galaxy dying pic

Local Galaxies can be divided into two main categories:

  • Star-forming or the gas-rich galaxies
  • Quiescent or the passive and gas-poor galaxies

Just how a galaxy exhausts and ceases to form stars is a process which was not understood clearly. One theory often promoted was the sudden removal of gas through outflows or stripping. An alternative theory is the so called “strangulation theory” in which the supply of cold gas to the galaxy is halted.

Dr Yingjie Peng and his team of astronomers from Cambridge University’s Cavendish Laboratory and Kavli Institute of Cosmology used data obtained from the Sloan Digital Sky Survey to analyze metal levels in more than 26,000 local galaxies.

The scientists learnt that quick deaths tended to be more spectacular and happened when the galaxy lost its supply of gas and its levels of metals remained static.

However if a galaxy continued to accumulate metals after its source of gas which it uses to create stars is exhausted, the death would be slow and deliberate.

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