- #1
- 22,196
- 6,873
In the early-morning hours of today, 14 October 2022, astronomers using the Gemini South telescope in Chile operated by NSF's NOIRLab observed the unprecedented aftermath of one of the most powerful explosions ever recorded, Gamma-Ray Burst GRB221009A.
This record-shattering event, which was first detected on 9 October 2022 by orbiting X-ray and gamma-ray telescopes, occurred 2.4 billion light-years from Earth and was likely triggered by a supernova explosion giving birth to a black hole.
The GRB, identified as GRB 221009A, occurred approximately 2.4 billion light-years away in the direction of the constellation Sagitta. It was first detected the morning of 9 October by X-ray and gamma-ray space telescopes, including NASA's Fermi Gamma-ray Space Telescope, Neil Gehrels Swift Observatory, and the Wind spacecraft .
Of note are other extraordinary reports of disturbances in the Earth's ionosphere affecting long wave radio transmissions from the energetic radiation from the GRB221009A event. Scientists are also wondering how very-high-energy 18 TeV (tera-electron-volt) photons observed with the Chinese Large High Altitude Air Shower Observatory could defy our standard understanding of physics and survive their 2.4 billion year journey to Earth.
No. GRB221009A is 10-15,000 times further away. That means the neutrino rate is 100's of millions of times smaller. In 1987A we saw a few dozen neutrinos.Cerenkov said:is it reasonable to expect neutrino detections from GRB221009A?
That's part of the challenge, in addition to the low probability of interaction. As V50 indicated the flux falls off as 1/d2, where d is the distance from source to observer.Cerenkov said:Is it the inverse square law that makes neutrino detection so difficult at great distances?
On October 9, 2022, an intense pulse of gamma-ray radiation swept through our solar system, overwhelming gamma-ray detectors on numerous orbiting satellites, and sending astronomers on a chase to study the event using the most powerful telescopes in the world.
. . . .
The gamma-ray emission from GRB 221009A lasted over 300 seconds. Astronomers think that such "long-duration" GRBs are the birth cry of a black hole, formed as the core of a massive and rapidly spinning star collapses under its own weight. The newborn black hole launches powerful jets of plasma at near the speed of light, which pierce through the collapsing star and shine in gamma-rays.
The Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS), together with some 40 research institutions worldwide, has released their latest discoveries on the brightest gamma-ray burst (dubbed as GRB 221009A) ever detected by humans.
. . . .
With the unique observations made by two Chinese space telescopes, namely Insight-HXMT and GECAM-C, scientists were able to accurately measure how bright the burst was and how much energy it released, which is the key to understand this historical event.
For this historic gamma-ray burst, another ground-based facility led by IHEP, Large High Altitude Air Shower Observatory (LHAASO), carried out joint observation with Insight-HXMT and the GECAM-C telescopes. LHAASO made several important first discoveries with its large amount of very high energy observation data, which will be reported later.
As the most energetic explosion phenomenon in the universe, GRBs could be produced by the core collapse of a massive star, which typically lasts longer than two seconds, or the merger of two compact stars, such as neutron stars and black holes, which typically lasts less than two seconds and usually emits gravitational waves. GRB 221009A belongs to the former.
and also mentionsNo evidence of associated supernova, and afterglow radio data contradicts current models.
“Twenty-five years of afterglow models that have worked very well cannot completely explain this jet,” said Kate Alexander, an astronomer at the University of Arizona in Tucson. “This [new radio component] may indicate additional structure within the jet or suggest the need to revise our models of how GRB jets interact with their surroundings.”
I am not an astronomer, but I think it is perhaps more to be taken as a statement of estimated probability. That is, given how often we observe GRB's and how their energies tend to distribute then (I assume) you can work our some statistics of this. I am not sure if such estimate also depend strongly on the "effects" of the underlying theory of GRB, but if it does it is a bit strange Kate Alexander in same interview both say this event is not following the models and also stick with the estimate at the same time.JLowe said:I'm no astronomer, but its hard for me to believe the brightest gamma ray burst to hit Earth in 10k years happened to hit a few years after we built the telescopes to see it.
I would tend to suspect that it should say our models predict that such bursts come by every ten millenia. As you say, we haven't been watching the sky in gamma frequencies long enough to know that directly.JLowe said:I'm no astronomer, but its hard for me to believe the brightest gamma ray burst to hit Earth in 10k years happened to hit a few years after we built the telescopes to see it.
Cosmic gamma ray bursts (GRBs) were discovered by accident in the late 1960's by satellites designed to detect gamma rays produced by atomic bomb tests on Earth. The GRBs appear first as a brilliant flash of gamma rays, that rises and falls in a matter of minutes. These bursts are often followed by afterglows at X-ray, optical and radio wavelengths.
A major leap forward in understanding the source of cosmic GRBs was made when the Burst and Transient Source Experiment (BATSE) was launched aboard the Compton Gamma Ray Observatory in 1991.
BATSE had an all-sky monitor that was capable of detecting a GRB virtually anywhere in the sky. Over a period of 9 years BATSE recorded thousands of GRBs, about 1 per day. Among other things, these results showed that the bursts occurred at random all over the sky. If the bursts were associated with objects in our Milky Way Galaxy, they would not show such a universal distribution. Rather, they would be concentrated along the plane of our galaxy like most of the matter in the Milky Way. The BATSE data was so good that it allowed astronomers to also rule out the possibility that the GRBs might be originating in the halo of our galaxy.
In 1997, astronomers were able to use the Beppo-Sax satellite to refine the location of several GRBs by observing their X-ray afterglow. Then the Hubble Space Telescope and other optical telescopes were used to study the optical afterglow of the GRBs and were able to precisely locate them in galaxies billions of light years from Earth. At such great distances, a GRB must produce enormous amounts of energy. While at their peak, which lasts only a few seconds, they have a power output that is comparable to that of all the galaxies in the universe!
the Chandra observation of GRB991216 provides evidence for a large, iron-rich cloud moving away from the site of the burst. Although much more work needs to be done, this observation would appear to support the hypernova model.
https://www.nasa.gov/feature/goddar...what-may-be-a-1-in-10000-year-gamma-ray-burst“GRB 221009A was likely the brightest burst at X-ray and gamma-ray energies to occur since human civilization began,” said Eric Burns, an assistant professor of physics and astronomy at Louisiana State University in Baton Rouge. He led an analysis of some 7,000 GRBs – mostly detected by NASA’s Fermi Gamma-ray Space Telescope and the Russian Konus instrument on NASA’s Wind spacecraft – to establish how frequently events this bright may occur. Their answer: once in every 10,000 years.
A Gamma-Ray Burst (GRB) is a highly energetic explosion that releases powerful bursts of gamma rays, the most energetic form of electromagnetic radiation. These bursts are believed to be caused by the collapse of massive stars or the merging of neutron stars.
GRB221009A lasted for approximately 14 seconds, making it one of the shortest recorded GRBs. However, the energy released during this short burst was equivalent to the energy emitted by the sun over the course of 10,000 years.
GRB221009A is considered a record-breaking event because it is the shortest GRB ever recorded with a known distance. This allows scientists to study the burst in more detail and gain a better understanding of the mechanisms behind these powerful explosions.
GRBs are some of the most energetic events in the universe, and studying them can provide valuable insights into the physics of extreme environments. They can also serve as important tools for studying the early universe and the formation of galaxies.
By studying GRB221009A, scientists can gain a better understanding of the mechanisms behind these powerful explosions and potentially uncover new information about the nature of the universe. The record-breaking nature of this event also highlights the need for continued research and observation of GRBs to further our understanding of these rare and fascinating events.