What causes the weird, extragalactic quick radio bursts we’ve detected over the past decade? A brand new research of an unusually shiny supernova could have discovered the important thing to answering this query.
Clues from a Repeating Burst
When a mysterious millisecond radio pulse of extragalactic origin — a quick radio burst (FRB) — was not too long ago discovered to repeat, it gave astronomers a uncommon probability to seek out this supply’s host galaxy. FRB 121102 was remoted to a star-forming, low-metallicity dwarf galaxy situated roughly three billion light-years away, and a dimmer, persistent radio supply was found in the identical area that produced the bursts.
This localization lent help to at least one concept for the origin of FRB 121102 (and probably different FRBs): that the bursts are powered by a magnetized neutron star born many years in the past in a superluminous supernova.
Superluminous supernovae are a kind of stellar explosion not less than ten instances extra highly effective than customary supernovae. These supernovae could shine additional shiny as a result of beginning of a neutron star with extraordinarily sturdy magnetic fields — a magnetar — that spins on millisecond timescales, emitting radiation and winds as its magnetic fields decay and additional powering the explosion.
Within the superluminous-supernova clarification for FRBs, the magnetar born within the stellar explosion might, even a decade later, energy temporary radio bursts. As well as, it will producing a glowing nebula seen to us as a persistent radio supply.
A workforce of scientists has now sought to check this image by analyzing identified superluminous supernovae and trying to find indicators of co-located persistent or bursting radio sources. In a current publication led by Tarraneh Eftekhari (Harvard-Smithsonian Heart for Astrophysics), they element their first success.
Radio Supply Discovered
Utilizing the Very Massive Array, Eftekhari and collaborators found a persistent radio supply coincident with the superluminous supernova PTF10hgi, an explosion that went off 7.5 years in the past, roughly 1.5 billion light-years away. That is the primary time a radio supply of any type has ever been related to a superluminous supernova, offering an necessary hyperlink between these explosions and different phenomena.
The authors check quite a lot of completely different potential origins for the radio emission seen, like star formation exercise, an lively galactic nucleus, and a supernova blast wave. Although none of those situations can but be dominated out with certainty, Eftekhari and collaborators present that every of them is very unlikely.
As a substitute, the radio emission is extraordinarily paying homage to the persistent radio supply related to FRB 121102. The authors present that all the observations are in line with a magnetar central engine powering a glowing nebula embedded within the supernova ejecta. And whereas a bursting radio supply wasn’t discovered coincident with the supernova, the authors’ observations had been solely 40 minutes lengthy; an extended remark time could but uncover a co-located FRB.
The authors element future observations that ought to have the ability to rule out different origins for the radio emission and strengthen the case for a superluminous-supernova-born magnetar as a supply of quick radio bursts. Within the meantime, it’s thrilling to observe because the items of this puzzle begin to come collectively!
“A Radio Supply Coincident with the Superluminous Supernova PTF10hgi: Proof for a Central Engine and an Analog of the Repeating FRB 121102?,” T. Eftekhari et al 2019 ApJL 876 L10. doi:10.3847/2041-8213/ab18a5
This publish initially appeared on AAS Nova, which options analysis highlights from the journals of the American Astronomical Society.