The possibility that someone out there is trying to
communicate with us has led to various efforts to analyze sounds produced by
our universe. Of these sounds, fast radio
bursts (FRBs) are one of the most intriguing types. Discovered only
rather recently, FRBs, or “cosmic whistles,” are flashes of energy — radio
chirps — that exist for just a few milliseconds at a time but can
generate as much energy as 500 million suns.
To date, fewer than 20 of these FRBs have
been picked up, but scientists didn’t quite know what or who caused them — until now.
Using a global network of powerful telescopes, a
team of astronomers finally managed to pinpoint one of the sources of these
highly unusual signals from space. Their study, which is published in
multiple papers in Nature and the Astrophysical Journal Letters, describes how they were
able to identify an FRB coming from a dwarf galaxy that’s about three billion
light-years away.
The enigmatic radio signal in question is called FRB 121102, and it was discovered two years ago by Shami
Chatterjee of Cornell University’s Department of Astronomy and his colleagues.
This particular FRB was interesting because the signals broadcasted seemed to
be repeated, which narrowed down the possible sources of FRBs.
Credits: Danielle Futselaar
“We knew that it has to be some mechanism that is
capable of repetition, it can’t be neutron stars crashing into each other and
destroying themselves or something like that.” Chatterjee explained to National Geographic.
The team was able to locate the source of FRB 121102
using very powerful satellites. First, they dedicated all 27 of the
82-foot-wide satellite dishes at New Mexico’s Very Large Array radio
observatory to the task. After a period of six months that included 83
hours-worth of observations, the team managed to capture nine images of FRB
121102. Next, they used the powerful Gemini optical telescope to narrow the source of FRB
121102 to a dwarf galaxy about three billion light-years away from
Earth.
To confirm and verify these findings, the team took
another look at FRB 121102 using a network of powerful European telescopes. It
was then that, according to Chatterjee, FRB 121102 “went into hyperdrive,”
emitting bursts that repeated once every hour on average.
At that point, the team was able to pinpoint the
source of FRB 121102 as the very center of the dwarf galaxy, which happened to
be occupied by a supermassive black hole. This means that the fast radio bursts
could be caused by the black hole itself, or they could be the result of
something else near it, like the gaseous remnants of a supernova in the black
hole or a neutron star orbiting it.
Credits: Gemini Observatory/Aura/NRC
JUSTIFIED FASCINATION WITH FRBS
One of the most interesting things about FRBs is
that we have yet to detect any within our own galaxy. Because they only seem to
emanate from places many, many light-years away, Chatterjee believes that
understanding the phenomenon of FRBs can help us learn more about the
universe’s past.
“One possibility is that it has something to do with
the evolution of the universe, it’s something that happened three billion years
in the past, when the universe was slightly different than it is today. That’s
weird. It was going on three billion years ago, but not three million years
ago?” he said.
Alternatively, we could be receiving evidence
of local FRBs and dismissing them as interference caused by things like
cell phones, satellites, and radar, which would mean the phenomenon is ongoing.
Also, pinpointing a black hole as the source of FRB 121102 doesn’t mean that
all fast radio bursts are caused by the same conditions. There could be
different kinds that we just haven’t honed in on yet.
In any case, further study is required, and as more
information comes to light, we’ll gain a deeper understanding of the universe
in which we live.
References: National Geographic News, Astrophysical Journal Letters, Nature
Comments
Post a Comment