(ORDO NEWS) — The aftermath of the epic collision, which involved at least one neutron star, was filmed for the first time in millimeter-wave radio frequencies.
The result is a record of short-term gamma radiation. the ray burst is one of the most energetic ever observed and one of the brightest long afterglows we have ever seen.
The data could help scientists learn more about these extreme events and the impact they have on the space around them.
And there is incredible time-lapse footage of an event whose light appears to have traveled 6 to 9 billion light-years across the universe to be detected by the Atacama Large Millimeter/Submillimeter Array (ALMA) in November 2021.
“This short GRB was the first time we tried to observe such an event with ALMA,” said physicist Wen-fai Fong of Northwestern University.
“The last glow for short flashes is very hard to find, which is why it was impressive to capture this event shining so brightly.
After years of observing these bursts, this amazing discovery opens up a new area of research as it encourages us to observe more of these bursts with ALMA and other telescopes in the future.”
Gamma-ray bursts are the most powerful known explosions in the universe. In just 10 seconds, a gamma-ray burst can emit more energy than a star like the Sun emits in 10 billion years.
And they are important; as we saw in the first neutron star collision ever observed, it is in such explosions that elements heavier than iron are formed and ejected into the universe. The gold ring you wear on your finger is the result of an extreme stellar catastrophe.
We know that neutron star collisions produce a type of gamma-ray burst known as a transient gamma-ray burst, or GRB.
They last only milliseconds and leave behind a bright afterglow as the jet from the explosion collides with and interacts with the gas in the interstellar medium.
Usually these SGRBs are not observed in the radio range, which can be a bit tricky to interpret.
“These explosions take place in distant galaxies, which means that the light from them can be quite weak for our telescopes on Earth,” explained astrophysicist Tanmoy Laskar from Radboud University in the Netherlands.
“Before ALMA, millimeter-scale telescopes weren’t sensitive enough to detect these afterglows.”
Because this particular event, named GRB 211106A, happened so far away, it could not be detected by our current gravitational wave astronomical instruments.
The energetic X-rays accompanying the brief explosion were recorded by NASA‘s Neil Gerels Swift Observatory.
However, galaxies as far away as the outburst GRB 211106A are not detectable in X-ray wavelengths, and the dust in the region meant that Hubble’s optical observations were no better at pinpointing the source.
For this reason, scientists working only with the X-ray burst thought that the site of the explosion was relatively close.
So they turned to ALMA, where for the first time millimeter waves were used to observe and contextualize a gamma-ray burst event.
“The Hubble observations have revealed an unchanging field of galaxies,” Lascar said.
“The unprecedented sensitivity of ALMA allowed us to locate the gamma-ray burst in this field with greater accuracy, and it turned out that it is in another faint galaxy that is further away.”
“This, in turn, means that this brief gamma-ray burst is even more powerful than we first thought, making it one of the brightest and most energetic on record.”
When neutron stars collide, the result is spectacular: an explosion accompanied by jets of material that shoot out at a significant percentage of the speed of light.
If we’re lucky, these jets are oriented in such a way that one of them is directed more or less towards us, which we see the eruption as a gamma-ray burst.
The millimeter-wave observations allowed the researchers to measure some of the key properties of GRB 211106A; namely, the jet opening angle, which can be used to determine the frequency of bursts in the Universe, and a more accurate measurement of burst energy.
“Millimeter wavelengths can tell us about the density of the environment around the gamma-ray burst,” said astronomer Genevieve Schroeder of Northwestern University.
“And combined with X-rays, they can tell us about the true energy of the explosion. millimeter waves can be detected over a longer time than X-rays, millimeter radiation can also be used to determine the width of the gamma-ray burst jet.”
The researchers found that GRB 211106A has some unusual properties, both in its host galaxy and its energy profile.
This ultimately suggests that there is a greater variety of SGRB properties than currently believed, meaning that continued observation and classification of these events is warranted.
So while this may be the first millimeter foray into these incredible explosions, it is extremely unlikely that it will be the last.
“ALMA breaks the playing field in terms of its millimeter-wave capabilities and allows us to see the faint, dynamic universe in this type of light for the first time,” Fong said.
“After a decade of observing short gamma-ray bursts, it’s really amazing to see the power of using these new technologies to unlock unexpected gifts from the universe.”
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