Named ASASSN-15lh, the supernova is thought to belong to a class of objects known as “superluminous supernovas”, mysterious objects that shine far more brightly than the average star explosion, though scientists don’t yet have an explanation for what could cause these kinds of supernova. According to reports released by the Science Magazine, A Super Nova is the explosion of an existing star. Type I superluminous supernovae seen to date have all burst forth in dim galaxies both smaller in size and that churn out stars much faster than the Milky Way, but ASASSN-15lh’s galaxy appears even bigger and brighter than the Milky Way. In fact, it’s twice as bright as the previous record-holder.
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Yet in other ways, besides its brute power, ASASSN-15lh stands apart.
Many previously discovered superluminous supernovas come from galaxies smaller than our own but produce stars more quickly, perhaps suggesting that the galaxy itself could have something to do with the formation of these superluminous supernovas. The explosion annihilates most of the star as well as anything nearby. But it was spotted by the All Sky Automated Survey for Supernovae (ASAS-SN, pronounced “assassin”) collaboration.
Using this method, the astronomers can observe stars in galaxies that aren’t on the “map”, which is how they spotted ASASSN-15lh. “If it is offset, this would rule out the interpretation of this event as somehow related to the host galaxy’s central supermassive black hole – assuming it has one, as most massive galaxies do”, Ohio State astronomer Todd Thompson wrote in an email to Discovery News. When searching for supernovae, scientists usually look through an approved list of galaxies.
Yet astronomers believe that the heart of the explosion is an object just 10 miles across, possibly spinning at least 1,000 times a second to convert all its rotational energy into light with near 100 per cent efficiency.
“If it really is a magnetar, it’s as if nature took everything we know about magnetars and turned it up to 11”, Stanek said. It is, though, possible for massive stars to have low hydrogen levels. It must have shed its outer layers of hydrogen and helium shortly before it died, because those elements are absent from the supernova. CEO George Skestos and the Robert Martin Ayers Sciences Fund. ASAS-SN telescopes are hosted by the Las Cumbres Observatory Global Telescope Network. Astronomers call these cases magnetars. It could be, he says, that ASASSN-15lh is simply the sort of supernova produced by the deaths of the universe’s biggest stars, poorly understood objects that could be hundreds of times as massive as our Sun. It would take for instance the Sun to emit light for 90 billion years – 50 times the age of the Universe – to match the emissions given off by this one explosion.
Working with Jose Prieto at the Universidad Diego Portales in Chile and Kris Stanek, ASAS-SN’s co-principle investigator at Ohio State University, Dong realized the curious spectrum could match that of another superluminous supernovae observed in 2010, but only if the new spectrum had been significantly redshifted-stretched out by the expansion of the universe as it traversed vast cosmic distances.
ASAS-SN has discovered around 250 supernovae since 2014, including the latest one, which began to flare up in June 2015. “We might have a completely different version or story of what we think this object is”. “Supernovae also fundamentally change how galaxies evolve when they explode by ejecting energy and momentum into their surroundings”.
But as the extra-strong supernova were discovered, researchers developed models of how exploding stars could get that extra boost. The Hubble Space Telescope will be pressed into service this year as well. Thompson says this possibility has a few issues.
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Supernovae are what astronomers call transient events; they explode, and then they slowly fade.
