Astronomers unveil new—and puzzling—features of mysterious fast radio bursts

Quick radio bursts (FRBs) are millisecond-long cosmic explosions that every produce the vitality equal to the sun’s annual output. Greater than 15 years after the deep-space pulses of electromagnetic radio waves had been first found, their perplexing nature continues to shock scientists—and newly printed analysis solely deepens the thriller surrounding them.

Within the Sept. 21 problem of the journal Nature, sudden new observations from a collection of cosmic quick radio bursts by a world workforce of scientists—together with UNLV astrophysicist Bing Zhang—problem the prevailing understanding of the bodily nature and central engine of FRBs.

The cosmic FRB observations had been made in late spring 2021 utilizing the huge 5-hundred-meter Aperture Spherical radio Telescope (FAST) in China. The workforce, led by Heng Xu, Kejia Lee, Subo Dong from Peking College, and Weiwei Zhu from the Nationwide Astronomical Observatories of China, together with Zhang, detected 1,863 bursts in 82 hours over 54 days from an energetic quick radio burst supply referred to as FRB 20201124A.

“That is the most important pattern of FRB information with polarization info from one single supply”, stated Lee.

Latest observations of a quick radio burst from our Milky Way galaxy recommend that it originated from a magnetar, which is a dense, city-sized neutron star with an extremely highly effective magnetic discipline. The origin of very distant cosmological fast radio bursts, alternatively, stays unknown. And the newest observations go away scientists questioning what they thought they knew about them.

“These observations introduced us again to the drawing board,” stated Zhang, who additionally serves as founding director of UNLV’s Nevada Middle for Astrophysics. “It’s clear that FRBs are extra mysterious than what we’ve imagined. Extra multi-wavelength observational campaigns are wanted to additional unveil the character of those objects.”

What makes the newest observations shocking to scientists is the irregular, short-time variations of the so-called “Faraday rotation measure”, which is the energy of the magnetic discipline and density of particles within the neighborhood of the FRB supply. The variations went up and down throughout the first 36 days of commentary and immediately stopped over the past 18 days earlier than the supply quenched.

“I equate it to filming a film of the environment of an FRB supply, and our movie revealed a posh, dynamically evolving, magnetized atmosphere that was by no means imagined earlier than,” stated Zhang. “Such an atmosphere will not be straightforwardly anticipated for an remoted magnetar. One thing else could be within the neighborhood of the FRB engine, probably a binary companion,” added Zhang.

To watch the host galaxy of the FRB, the workforce additionally made use of the 10-m Keck telescopes situated at Mauna Kea in Hawaii. Zhang says that younger magnetars are believed to reside in energetic star-forming areas of a star-forming galaxy, however the optical picture of the host galaxy reveals that—unexpectedly—the host galaxy is a metal-rich barred spiral galaxy like our Milky Way. The FRB location is in a area the place there isn’t any important star-forming exercise.

“This location is inconsistent with a younger magnetar central engine shaped throughout an excessive explosion corresponding to an extended gamma-ray burst or a superluminous supernova, broadly speculated progenitors of energetic FRB engines,” stated Dong.

The examine, “A quick radio burst supply at a posh magnetized web site in a barred galaxy”, appeared September 21 within the journal Nature and consists of 74 co-authors from 30 establishments. Along with UNLV, Peking College, and the Nationwide Astronomical Observatories of China, collaborating establishments additionally embody Purple Mountain Observatory, Yunnan College, UC Berkeley, Caltech, Princeton College, College of Hawaii, and different establishments from China, the U.S., Australia, Germany, and Israel.