Title: Strange Signal Coming From the Milky Way detected!
Recently, two ground-based radio telescopes detected a pulse of radio waves.
And it was pretty intense.
This event astonished astronomers because it was the first time a fast radio burst (FRB)
had ever been detected so close to Earth.
But where does this signal come from?
What caused it?
Astronomers think they have an answer.
Do they?
Follow me in this video to get to know more about Fast radio bursts, what they are and
where they come from: I promise you won't regret it!
First of all, you'd probably want to know what a fast radio burst is.
Radio bursts, as the name suggests, are intense bursts of radio emission.
But why do we call them FAST?
Well, it's simple: they have durations of milliseconds.
Actually, they tend to exhibit the characteristic dispersion sweep of radio pulsars.
The first FRB was discovered in 2007, although it was actually observed some six years earlier,
in archival data from a pulsar survey of the Magellanic Clouds.
It was dubbed the “Lorimer Burst”.
The limited dynamic range of the instrumentation prohibited an exact measure of the flux, but
it has been estimated that several 100 bursts could occur every day with a small probability
of detection.
Scientists have dozens of theories about the causes of fast radio bursts, from colliding
black holes to alien starships.
Many theories suggest the bursts originate from neutron stars, which are corpses of stars
that died in catastrophic explosions known as supernovas.
FRB usually come from outside of our Galaxy.
But on April 28, 2020, two ground-based telescopes detected an intense pulse of radio waves.
Located just 30,000 light-years from our planet, the event was firmly within the Milky Way,
and it was, to all intents and purposes, almost impossible to miss.
It was detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Survey
for Transient Astronomical Radio Emission 2 (STARE2).
Until this point, as we said, all FRBs had been observed outside our galaxy, and because
of that, they were very hard to study.
April 2020's discovery was notable for two reasons:
The first one was the most energetic radio blast that astronomers have ever recorded
in the Milky Way.
The second one, scientists are now closer to determining the origin of FRBs than at
any point since they were first discovered.
The first fast radio burst was detected in 2007 when scientist Duncan Lorimer was studying
data taken by Australian telescopes.
A problem that arises while studying fast radio bursts, aside from most of them have
been so far away, is that they are...fast.
They are so fleeting.
They are bright and instantaneous flashes of light.
They are ephemeral.
Even if they can release as much energy in a few thousandths of a second as the sun in
100 years, they've been and gone in the blink of an eye.
That's why studying them is so hard.
Usually, when a major astronomical event happens, as in the case of a supernova, astronomers
focus one or more different telescopes on it, in order to have a lot of different data
to analyze.
But the ephemeral nature of these bursts removes any such opportunity.
But astronomers never give up, and now they have a piece of pretty good knowledge about
Fast radio bursts.
All of this knowledge was made possible by the study and detection of FRB coming from
outside our host galaxy.
Let's make a recap of what we know about them.
They last for microseconds to milliseconds.
Thousands of these bursts occur in the sky every single day.
Most of them come from billions of light-years away.
They come from very small sources, no more than a few hundred kilometres in size.
The most likely sources of this kind are neutron stars since they are both very small and very
energetic.
This is pretty much what we know...until now.
Because the Fast radio burst discovered in our Galaxy on Aprile, could now help us to
confirm or adjust such theories.
Thanks to the work that involved the data of other telescopes monitoring the same patch
of sky, observational evidence is now suggesting that the origin of FRBs is very likely a magnetar,
a type of young neutron star born from the embers of supernovas with a magnetic field
5,000 trillion times more powerful than Earth’s, thereby making them the universe’s most
powerful magnets.
But how did they come to this conclusion?
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Well, we must consider that magnetar is known to emit high energy electromagnetic radiation,
such as gamma rays and X rays, the most powerful radiation in the universe.
Both of these erupt in short-lived flares.
That's why magnetar is a good candidate for causing Fast radio bursts.
Also, this latest fast radio burst, which was dubbed FRB 200428, was found to have originated
in the Vulpecula constellation, which....guess what?
Happens to be hosting the magnetar SGR 1935+2154.
The first detection of X-rays from that sky region came the day before CHIME and STARE2
discovered FRB 200428 by the Fermi Gamma-ray space telescope.
Other telescopes were also found to have observed an X-ray burst from SGR 1935+2154 — crucially,
at the same time as the fast radio burst.
These included the Konus-Wind detector onboard NASA’s GGS-Wind spacecraft and the European
Space Agency’s INTEGRAL space telescope, both picking up an X-ray burst at the moment
CHIME and STARE2 recorded the FRB.
Now that we explained what could be causing FRB, let's take a look at the instrument we
use to discover and detect such radio signals.
The telescope, as we said, is called CHIME.
It is based at the Dominion Radio Astrophysical Observatory in Canada
Its work could be divided into 5 parts.
The first one is collecting radio signals.
A good FRB hunter, in fact, has to be sensitive to radio signals.
Something peculiar about CHIME is that there are no moving parts in the CHIME radio telescope.
Instead, as the Earth turns, radio waves that are emitted by celestial objects are received
from a narrow stretch of sky that runs from the northern to the southern horizon.
The second thing about CHIME is that it has cylindrical reflectors.
The radio waves are collected by four semi-cylindrical parabolic reflectors aligned north to south,
each one measuring 66 feet (20 meters) (by 328 feet (100 m) and lined up in a row.
With the northern sky scanned east to west every 24 hours, this gives a 200-square-degree
field of view.
The third part of the job is focal assembly.
What does it mean?
Well, you know radiation dives in our telescopes as polarized radiation.
In CHIME, it is received by 256 dual-polarization antennas that are lined up above the reflectors
and spaced 12 inches (30 centimetres) apart.
They are sensitive from 400 to 800 MHz in both linear polarizations.
The fourth part is, of course, processing the data.
Each microsecond of data results in 2,048 amplified analogue samples being processed
by an electronic system called the F-Engine, which is safely housed inside two shielded
20-foot (6 m) shipping containers.
The signals are digitized and then converted into a 1,024-element frequency spectrum.
Last but not least, the fifth part of CHIME's job is to make a spatial correlation.
The data is sent by optical cable to the GPU-based X-Engine housed in two shielded 40-foot shipping
containers.
It’s a 1,000-processor high-performance cluster that can figure out where the signals
are coming from and create an accurate sky map.
This is very useful to astronomers because their main purpose is to find what is causing
FRB and wherein the universe.
Anyway, just to be sure that CHIME has done its job well, the scientific community turned
its attention to the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) located in
southwest China.
Luckily, and I would add not surprisingly, the Chinese telescope detected a radio burst
in the direction of FRB 200428 too, and put its location around SGR 1935+2154, the magnetar
we were talking about.
What does this mean?
This means that the FRB came from the direction of a known magnetar within our galaxy and
the radio burst happened at exactly the same time as an X-ray burst coming from the same
magnetar.
This, of course, is a clue as to how magnetars produce FRBs, but the scientific community
is still trying to work out what it all means.
The importance of this discovery is twofold.
On one side, CHIME has proven to be an essential tool.
Based at the Dominion Radio Astrophysical Observatory in Canada, it’s a novel radio
telescope and it has a high mapping speed thanks to its 200-square-degree field of view
and broad frequency range of between 400MHz and 800MHz.
Most radio telescopes aren’t able to pinpoint the location of an FRB well enough to associate
it with a known object.
Those that are able to localize FRBs with great precision usually look at small patches
of sky, and can only observe a patch about the size of the full moon.
They are not able to monitor several known magnetars at once.
CHIME, however, observes an area about 500 times larger, and it can therefore monitor
all magnetars located in the northern sky every day, allowing us to detect a burst as
rare as this one.
It combines its localization capabilities with the large sky area, and that has allowed
us to both detect this burst and associate it with a known object.
On the other side, as we said before, this was a huge discovery because it happened inside
our galaxy, and could therefore help us to gain more precise knowledge about what is
causing Fast radio bursts, and how they're ejected.
This means we will soon have a more precise description of our universe.
This is probably the beauty of science.
Every discovery, starting from the smallest one to the biggest one, is important.
And contributes to our description of the universe as a little tiny piece in a big puzzling
puzzle.
And every time we accommodate a new piece, we are happy.
That's why humans love science.
That's why you love watching the insane curiosity channel!
" Thanks for watching everyone!
Do you think this new discovery will revolutionize our understanding of the universe?
Let us know in the comment below!