Immense set of mysterious fast radio bursts

Date:
October 13, 2021
Source:
University of Nevada, Las Vegas
Summary:
An international team of astronomers recently observed more
than 1,650 fast radio bursts (FRBs) detected from one source in
deep space, which amounts to the largest set -- by far -- of the
mysterious phenomena ever recorded. The source, dubbed FRB 121102,
was observed using the Five- hundred-meter Aperture Spherical
Telescope (FAST) in China, and represents more FRBs in one event
than all previous reported occurrences combined.



FULL STORY ==========================================================================
An international team of astronomers recently observed more than 1,650
fast radio bursts (FRBs) detected from one source in deep space, which
amounts to the largest set -- by far -- of the mysterious phenomena
ever recorded.


==========================================================================
More than a decade after the discovery of FRBs, astronomers are still
baffled by the origins of the millisecond-long, cosmic explosions that
each produce the energy equivalent to the sun's annual output.

In a study published in the Oct. 13 issue of the journal Nature,
scientists - - including UNLV astrophysicist Bing Zhang -- report on
the discovery of a total of 1,652 independent FRBs from one source
over the course of 47 days in 2019. The source, dubbed FRB 121102,
was observed using the Five-hundred-meter Aperture Spherical Telescope
(FAST) in China, and represents more FRBs in one event than all previous reported occurrences combined.

"This was the first time that one FRB source was studied in such great
detail," said Zhang, one of the study's corresponding authors. "The large
burst set helped our team home in like never before on the characteristic energy and energy distribution of FRBs, which sheds new light on the
engine that powers these mysterious phenomena." Since FRBs were first discovered in 2007, astronomers worldwide have turned to powerful radio telescopes like FAST to trace the bursts and to look for clues on where
they come from and how they're produced. The source that powers most FRBs
is widely believed to be magnetars, incredibly dense, city-sized neutron
stars that possess the strongest magnetic fields in the universe. And
while scientists are gaining greater clarity on what produces FRBs,
the exact location of where they occur is still a mystery.

A mystery that recent results may be starting to unravel.



========================================================================== According to Zhang, there are two active models for where FRBs come
from. One could be that they come from magnetospheres, or within a
magnetar's strong magnetic field. Another theory is that FRBs form
from relativistic shocks outside the magnetosphere traveling the speed
of light.

"These results pose great challenges to the latter model," says
Zhang. "The bursts are too frequent and -- given that this episode
alone amounts to 3.8% of the energy available from a magnetar -- it adds
up to too much energy for the second model to work." The bursts were
measured by FAST within a total of 59.5 hours over 47 days from Aug. 29
to Oct. 29, 2019.

"During its most active phase, FRB 121102 included 122 bursts measured
within a one-hour period, the highest repeat rate ever observed for any
FRB," said Pei Wang, one of the article's lead authors from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC).

Researchers expect that FAST will continue to systematically investigate
a large number of repeating FRBs in the future.

"As the world's largest antenna, FAST's sensitivity proves to be conducive
to revealing intricacies of cosmic transients, including FRBs," said Di
Li, the study's lead researcher from NAOC.

The study includes more than 30 co-authors from 16 institutions in
four countries and is part of a long-running collaboration among the institutions.

In addition to UNLV and NAOC, collaborating institutions include Guizhou
Normal University, Cornell University, Max Planck Institute for Radio Astronomy, West Virginia University, CSIRO Astronomy and Space Science, University of California Berkeley, and Nanjing University.

========================================================================== Story Source: Materials provided by
University_of_Nevada,_Las_Vegas. Original written by Tony Allen. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. D. Li, P. Wang, W. W. Zhu, B. Zhang, X. X. Zhang, R. Duan,
Y. K. Zhang,
Y. Feng, N. Y. Tang, S. Chatterjee, J. M. Cordes, M. Cruces,
S. Dai, V.

Gajjar, G. Hobbs, C. Jin, M. Kramer, D. R. Lorimer, C. C. Miao,
C. H.

Niu, J. R. Niu, Z. C. Pan, L. Qian, L. Spitler, D. Werthimer, G. Q.

Zhang, F. Y. Wang, X. Y. Xie, Y. L. Yue, L. Zhang, Q. J. Zhi &
Y. Zhu. A bimodal burst energy distribution of a repeating fast
radio burst source.

Nature, 2021 DOI: 10.1038/s41586-021-03878-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211013131611.htm

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