- 4011
- BRIGHTEST SUPERNOVA
- lasting 3 years.
Astronomers have witnessed the largest explosion in space. The explosive event labeled AT2021lwx was
observed to be ten times brighter than any known supernova, the explosions that
occur as massive stars die. Supernova
explosions only last a few months, this explosive event has been raging for at
least three years.
--------------- 4011 - BRIGHTEST SUPERNOVA - lasting 3 years
-
“AT2021lwx” is three times brighter than the light that is emitted as
stars are ripped apart and devoured by supermassive black holes, called "tidal disruption events" or
"TDEs." The blast is around 8 billion light-years from Earth and thus
occurred when the universe was just 6 billion years old.
-
- This
supernova was first spotted by the Zwicky Transient Facility in California in
2020 and was then picked up by the Asteroid Terrestrial-impact Last Alert
System (ATLAS) based in Hawaii.
-
- Both
of these systems are designed to survey the night sky for astronomical events
that rapidly change in brightness over time, known as "transients."
This change in brightness can indicate a supernova or a gamma-ray burst (GRB)
deep in the universe or something much closer to home like a comet or an
asteroid.
-
- Though
it was spotted by these facilities three years ago, the sheer scale and power
of the explosion AT2021lwx were unknown until now. Most supernovae and TDEs only last for a
couple of months before fading away. For something to be bright for two plus
years was immediately very unusual.
-
-
“AT2021lwx” may be the result of a black hole violently disrupting a
cloud of gas with a mass thousands of times greater than the sun. As it did so,
the black hole swallowed fragments of the gas cloud, sending shockwaves into
both what remains of the gas and into a wider donut-shaped torus of dust
surrounding it, causing them to emit bright electromagnetic radiation.
-
- Events
like this have been witnessed before, they are rare. What's more, none that
have been witnessed previously have been on the scale of AT2021lwx. While it is not actually as bright as the
gamma-ray burst GRB 221009A spotted by astronomers in 2022, this event that
erupted from 2.4 billion light-years away lasted for just ten hours after
detection. Even though that is quite long for a GRB, it means that AT2021lwx
has put out far more energy over its entire lifetime than this gamma-ray burst
did in its own.
-
-
Measuring the power of a cosmic explosion used the spectrum of light
that was emitted from the event and split down into its constituent
wavelengths, measuring how light was emitted and absorbed around the event.
This allowed the researchers to calculate the distance to the source.
-
- Once
you know the distance to the object and how bright it appears to us, you can
calculate the brightness of the object at its source. The only thing in the known universe that is
as bright as AT2021lwx are supermassive black holes. When these black holes
feed on stellar gases that fall into them at high velocities, they can let off
incredibly bright emissions known as “quasars”.
-
- With
a quasar, we see the brightness flickering up and down over time. But looking back over a decade there was no
detection of AT2021lwx, then suddenly it appears with the brightness of the
brightest things in the universe, which is unprecedented.
-
-
Though there are other possible explanations for the explosive event,
the astronomers currently favor the explanation that sees an extremely large
cloud of mostly gaseous hydrogen or dust that was knocked from its orbit around
the black hole and sucked into it. This will only be conclusively determined
when the team has collected more data about AT2021lwx.
-
- The
team will now look at the explosion in different wavelengths of light including
X-rays. Doing so could reveal the temperature of the event and what processes
are driving it. They will also conduct computer simulations to discover if
their model of a titanic gas cloud disrupted by a black hole could account for
AT2021lwx.
-
-With new facilities, like the “Vera Rubin
Observatory's Legacy Survey of Space and Time”, coming online in the next few
years, we are hoping to discover more events like this and learn more about
them.
-It could be that these events, although
extremely rare, are so energetic that they are key processes to how the centers
of galaxies change over time.
-
May 17, 2023 BRIGHTEST SUPERNOVA
- lasting 3 years 4011
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------ “Jim Detrick” -----------
--------------------- --- Wednesday, May 17, 2023
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