These results show that the amount of metals has at most only a small effect on the properties
of a superluminous supernova and the engine driving it.
The Dark Energy Survey has discovered a number
of superluminous supernovae and continues to see more distant cosmic explosions revealing how stars exploded during the strongest period of star formation.
Previous observations
of superluminous supernovae found they typically reside in low - mass or dwarf galaxies, which tend to be less enriched in metals than more massive galaxies.
«What we really want to know is the relative rate
of superluminous supernovae to normal supernovae, but we can't yet make that comparison because normal supernovae are too faint to see at that distance.
These new discoveries belong to a special subclass
of superluminous supernovae that have no hydrogen.
Not exact matches
Thousands
of supernovas have happened in the past decade, but only about 50
of them were «
superluminous,» meaning they were 100 times brighter than usual supernovas.
In fact, SN 2017egm was not only
superluminous, but superclose: At just 420 million light - years away, it was three times closer than any other observed supernova
of its type.
«
Superluminous supernovas were already the rock stars
of the supernova world,» Matt Nicholl, lead author
of the study and an astronomer at the Harvard - Smithsonian Center for Astrophysics in Cambridge, Massachusetts, said in the statement.
A rare,
superluminous kind
of stellar explosion does not fit into the usual supernova categories
Extremely bright exploding stars, called
superluminous supernovae, and long gamma ray bursts also occur in this type
of galaxy, he noted, and both are hypothesized to be associated with massive, highly magnetic and rapidly rotating neutron stars called magnetars.
One
of the newly discovered supernovae, named SNLS - 06D4eu, is the most distant and possibly the most luminous member
of an emerging class
of explosions called
superluminous supernovae.
«The current idea is that a low - metal environment is important in creating
superluminous supernovae, and that's why they tend to occur in low mass galaxies, but DES15E2mlf is in a relatively massive galaxy compared to the typical host galaxy for
superluminous supernovae,» said Pan, a postdoctoral researcher at UC Santa Cruz and first author
of the paper.
Superluminous supernovae are 10 to 100 times brighter than a typical supernova resulting from the collapse
of a massive star.
Following the recent discovery
of one
of these «
superluminous supernovas,» a team
of astronomers led by Matt Nicholl from the Harvard - Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., has uncovered vital clues about where some
of these extraordinary objects come from.
While the brightness
of SN 2017egm and the properties
of the magnetar that powers it overlap with those
of other
superluminous supernovas, the amount
of mass ejected by SN 2017egm may be lower than the average event.
And, according to Laura Spitler, namesake
of the Spitler burst and a researcher at the Max Planck Institute for Radio Astronomy, in Bonn, Germany, magnetars generally form from stellar explosions called Type - I
superluminous supernovas.
Another idea floating around is that FRBs are emitted by active galactic nuclei, or AGNs —
superluminous regions at the centers
of some galaxies.
«There are also two other classes
of extreme events — long duration gamma - ray bursts and
superluminous supernovae — that frequently occur in dwarf galaxies, as well.