Fans of “The Late Show with David Letterman” will remember a recurring segment called “Is this anything?” where the host and the bandleader Paul Schaffer would watch some strange event and then debate about whether it was anything to be impressed with, afraid of, etc. Ever since the millisecond-long fast radio bursts (FRBs) were detected by astronomers in 2007, space scientists and the general public have been trying decide if they’re anything. Are they signals from an alien civilization? Are they hyperflares from equally mysterious magnetars? If they repeat regularly, then what? Well, get ready to play again because the only known source of FRBs in the Milky Way just sent another burst. Is this anything?
“SGR J1935+2154, the host magnetar of the Galactic FRB200428 (ATel #13681, #13684), was reported to be radio-active again on 2020 Oct 8th by CHIME/FRB team (ATel #14074, #14080). There was one marginal detection of the magnetar’s pulsed radio emission at 408 MHz by the Medicina Northern Cross (ATel #13783) despite many attempts (ATel #13713, #13726, #13778, #13838). FAST observed this magnetar for one hour on 2020 Oct 9th at 1.25 GHz with a bandwidth of 460MHz and detected multiple radio pulses with fluence up to 40 mJy ms.”
That post on the pro astronomers bulletin board ‘The Astronomer’s Telegram’ reports than the CHIME/FRB team (Canadian Hydrogen Intensity Mapping Experiment) was watching the Milky Way magnetar SGR 1935+2154 (30,000 light years from Earth) on October 8 when it emitted three millisecond radio bursts in three seconds, followed by a pulsed radio emission that matched the magnetar’s spin period. SGR 1935+2154 has been under close watch since April 2020 when it emitted its first FRBs, making it the first in the Milky Way and one of only two dozen magnetars ever discovered. Magnetars are neutron stars (collapsed super-giants) with unusually powerful magnet fields, and the discovery led astronomers to answer ‘Yes’ to the ‘Is this anything’ question – this is the first confirmed cause of FRBs. It may not be the only one, but it’s definitely the first.
“It’s really exciting to see SGR 1935+2154 back again, and I’m optimistic that as we study these bursts more carefully, it will help us better understand the potential relationship between magnetars and fast radio bursts.”
Astronomer Deborah Good of the University of British Columbia in Canada and a member of the CHIME/FRB, confirmed to ScienceAlert that this is something, especially since the three bursts occurred within one rotation period of the magnetar, with two of them close together. Good called this “a bit unusual” and something the CHIME/FRB team would analyze, but the report in ‘The Astronomer’s telegram’ reveals why this set of bursts could be a BIG something.
“Based on these results and the increasing bursting activities, we speculate that the magnetar may be in the process of turning into an active radio pulsar.”
Radio pulsars are rapidly spinning neutron stars that emit radio radiation from their poles in millisecond pulses. This means SGR 1935+2154 may be more than a magnetar – it may be the missing link between magnetars and radio pulsars.
And THAT would be something.