Scientists successfully predict resumption of bursts from magnetar

The uncertainty of science: Though they have no real idea why it happens, scientists have now successfully predicted the resumption of energetic bursts coming from a magnetar and according to schedule.

The researchers — Grossan and theoretical physicist and cosmologist Eric Linder from SSL and the Berkeley Center for Cosmological Physics and postdoctoral fellow Mikhail Denissenya from Nazarbayev University in Kazakhstan — discovered the pattern last year in bursts from a soft gamma repeater, SGR1935+2154, that is a magnetar, a prolific source of soft or lower energy gamma ray bursts and the only known source of fast radio bursts within our Milky Way galaxy. They found that the object emits bursts randomly, but only within regular four-month windows of time, each active window separated by three months of inactivity.

On March 19, the team uploaded a preprint claiming “periodic windowed behavior” in soft gamma bursts from SGR1935+2154 and predicted that these bursts would start up again after June 1 — following a three month hiatus — and could occur throughout a four-month window ending Oct. 7.

On June 24, three weeks into the window of activity, the first new burst from SGR1935+2154 was observed after the predicted three month gap, and nearly a dozen more bursts have been observed since, including one on July 6.

They made this prediction based on data going back to 2014 that showed the three-month-off/four-month-on pattern.

As to why this pattern exists, they presently have no idea. Theories have been proposed, such as starquakes activated by the magnetar’s fast rotation or blocking clouds of gas, but none are really very convincing, or are backed with enough data.

First fast radio burst detected in Milky Way

Astronomers using both space- and ground-based telescopes have detected for the first time a fast radio burst occurring inside the Milky Way, finding that it came from a magnetar, a pulsar with an extremely powerful magnetic field.

The radio component was discovered by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a radio telescope located at Dominion Radio Astrophysical Observatory in British Columbia and led by McGill University in Montreal, the University of British Columbia, and the University of Toronto.

A NASA-funded project called Survey for Transient Astronomical Radio Emission 2 (STARE2) also detected the radio burst seen by CHIME. Consisting of a trio of detectors in California and Utah and operated by Caltech and NASA’s Jet Propulsion Laboratory in Southern California, STARE 2 is led by Bochenek, Shri Kulkarni at Caltech, and Konstantin Belov at JPL. They determined the burst’s energy was comparable to FRBs.

By the time these bursts occurred, astronomers had already been monitoring their source for more than half a day.

Late on April 27, NASA’s Neil Gehrels Swift Observatory spotted a new round of activity from a magnetar called SGR 1935+2154 (SGR 1935 for short) located in the constellation Vulpecula. It was the object’s most prolific flare-up yet – a storm of rapid-fire X-ray bursts, each lasting less than a second. The storm, which raged for hours, was picked up at various times by Swift, NASA’s Fermi Gamma-ray Space Telescope, and NASA’s Neutron star Interior Composition Explorer (NICER), an X-ray telescope mounted on the International Space Station.

Later observations detected X-rays from the same source. While this does not prove that all fast radio bursts come from magnetars, it does prove that at least some do.