samedi 25 juin 2016

The most luminous supernova to date

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June 25, 2016

Astronomers have spotted the most powerful supernova in human history. The record-breaking cosmic explosion was 570 billion times brighter than the Sun and about 200 times more powerful than a typical supernova, scientists said. The blast - known as ASASSN-15lh- is thought to be an example of a "superluminous supernova," a recently discovered type of explosion unleashed by certain stars when they die.

Astronomers spot most powerful supernova in human history

Supernovae are exploding stars at the end of their lives, providing an input of heavy elements and energy into galaxies. Some types have near-identical peak brightness, but in recent years a new class of superluminous supernovae has been found. Dong et al.y report the discovery of ASASSN-15lh (SN 2015L), the most luminous supernova yet found by some margin. It appears to originate in a large quiescent galaxy, in contrast to most super-luminous supernovae, which typically come from star-forming dwarf galaxies. The discovery will provide constraints on models of superluminous supernovae and how they affect their host galaxies.

ASAS SN 15lh is 570 billion times brighter than the Sun


We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = –23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 1045 ergs s–1, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ –25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 1052 ergs, challenging the magnetar model for its engine.

"ASASSN-15lh may lead to new thinking and new observations of the whole class of superluminous supernova."

ASAS SN 15lh "superluminous" supernova explosion

The explosion, described in a study published in the Science journal, was first glimpsed in June and took place around 3.8 billion light years away. It was more than twice the brightness of the previous record-holding supernova and 20 times that of the 100 billion stars in the Milky Way. The event was spotted by two telescopes in Chile as part of an international space survey based at America's Ohio State University.

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Images, Video, Text, Credits: Ohio State University/Austrlian National University/Pasadena Technology Time/ Aerospace.


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