NOIRLab: The ‘Brightest of All Time’ Gamma-Ray Burst and Its Ordinary Supernova

[bystander]

The ‘Brightest of All Time’ Gamma-Ray Burst and Its Ordinary Supernova
NOIRLab Stories | 2023 Jun 14

One of the closest and most powerful gamma-ray bursts (GRBs) ever seen could change the way that we think about these titanic explosions.

Credit: International Gemini Observatory/NOIRLab/NSF/AURA/B. O'Connor (UMD/GWU) & J. Rastinejad & W Fong (Northwestern Univ); Image processing: T.A. Rector (Univ of Alaska Anchorage/NOIRLab), J. Miller, M. Zamani & D. de Martin (NOIRLab)

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A team of astronomers using the Gemini South telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, have observed the ‘brightest of all time’ long gamma-ray burst. Using Gemini South's Multi-Object Spectrograph (GMOS) instrument, the team found that although GRB 221009A exhibits a jet structure as rare as it is bright, its associated supernova is surprisingly ordinary.

On 9 October 2022 a flash of high-intensity gamma rays was detected by NASA’s Swift satellite coming from a galaxy 1.9 billion light-years away. Dubbed the ‘BOAT’ — the ‘brightest of all time’ — GRB 221009A was so exceptionally powerful that it actually sent shockwaves through Earth’s ionosphere, the outer layer of our planet’s atmosphere. ...

While most GRBs of this type take place much farther away, GRB 221009A’s relative proximity has given astronomers an unprecedented look into its central engine. In fact, the combination of intense brightness and closeness is so rare that astronomers don’t expect to see another GRB like it for another 1000 years on average. ...

Using the Gemini South telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, authors on two papers about this discovery, O’Connor and Srinivasaragavan, observed the explosion associated with GRB 221009A. One paper examines the ‘opening angle’ of the GRB jet, which can provide information about the process that emits the gamma rays, while the second paper described the search for the GRB’s optical counterpart — a supernova. ...

The supernova SN 2022xiw turned out to be surprisingly underwhelming and not unlike other supernovae. ...

A Structured Jet Explains the Extreme GRB 221009A ~ Brendan O'Connor et al

• Sciance Advances 9(23) (07 Jun 2023) DOI: 10.1126/sciadv.adi1405
• arXiv > astro-ph > arXiv:2302.07906 > 15 Feb 2023

A Sensitive Search for Supernova Emission Associated
with the Extremely Energetic and Nearby GRB 221009A ~ Gokul P. Srinivasaragavan et al

• Astrophysical Journal Letters 949(2):L39 (2023 Jun 01) DOI: 10.3847/2041-8213/accf97
• arXiv > astro-ph > arXiv:2303.12849 > 22 Mar 2023 (v1), 29 May 2023 (v3)

Record-Breaking Gamma-Ray Burst Possibly Most Powerful Explosion Ever Recorded
NOIRLab Photo Release | Gemini Observatory | 2022 Oct 14

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[Chidortmund]

How significant are the facts that 221009A had synchrotron radiation and the jet was directed at earth? It is way outside my bailiwick but I’ve only heard “synchrotron” when referring to particle accelerators, I know they occur in nature but is that common? And they say the jet was directly pointed at earth but I’m not sure how significant that is. If the jet is a fixed diameter of 1,000 miles it would seem unusual that it hit earth after traveling 2 billion light years. If that jet was trillions of miles across, it would seem less odd.

[Chris Peterson]

How significant are the facts that 221009A had synchrotron radiation and the jet was directed at earth? It is way outside my bailiwick but I’ve only heard “synchrotron” when referring to particle accelerators, I know they occur in nature but is that common? And they say the jet was directly pointed at earth but I’m not sure how significant that is. If the jet is a fixed diameter of 1,000 miles it would seem unusual that it hit earth after traveling 2 billion light years. If that jet was trillions of miles across, it would seem less odd.

Synchrotron radiation is very common in the Universe, occurring when charged particles travel along (or spiral along) magnetic field lines. All beams spread over distance; certainly, this one was very wide when it intersected our planet. Probably light years wide.

[Ann]

How significant are the facts that 221009A had synchrotron radiation and the jet was directed at earth? It is way outside my bailiwick but I’ve only heard “synchrotron” when referring to particle accelerators, I know they occur in nature but is that common? And they say the jet was directly pointed at earth but I’m not sure how significant that is. If the jet is a fixed diameter of 1,000 miles it would seem unusual that it hit earth after traveling 2 billion light years. If that jet was trillions of miles across, it would seem less odd.

The Crab Nebula supernova remnant is famous for its synchrotron radiation:

Central part of the Crab Nebula. The neutron star is the one farthest to the right of the two bright stars near the center. The thick red strands are ionized hydrogen (along with other ionized elements), while the ghostly glow is synchrotron radiation. Credit: ESA/Hubble & NASA. Acknowledgement: Mahdi Zamani.

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Wikipedia wrote:

In 1953, Iosif Shklovsky proposed that the diffuse blue region is predominantly produced by synchrotron radiation, which is radiation given off by the curving motion of electrons in a magnetic field. The radiation corresponded to electrons moving at speeds up to half the speed of light.[37] Three years later the theory was confirmed by observations. In the 1960s it was found that the source of the curved paths of the electrons was the strong magnetic field produced by a neutron star at the centre of the nebula.

As for the width of the jet, I am absolutely the wrong person to discuss math with you. However, the gamma ray burst in this case was more nearby than GRBs typically are, and so could probably stay better collimated.

I found this illustration by Brendan O'Connor et al:

The way I understand the illustration, it was the initial gamma ray that was extremely collimated ("narrow"). Waves of progressively lower energy were more spread out. If that is typically the case, then the Earth would not often be taking a direct hit from the most intense, narrow beam of a gamma ray burst.

Ann

[AVAO]

The Crab Nebula supernova remnant is famous for its synchrotron radiation:

Central part of the Crab Nebula. The neutron star is the one farthest to the right of the two bright stars near the center. The thick red strands are ionized hydrogen (along with other ionized elements), while the ghostly glow is synchrotron radiation. Credit: ESA/Hubble & NASA. Acknowledgement: Mahdi Zamani.

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Ann

Click to view full size image

[rewardpoor]

The Crab Nebula supernova remnant is famous for its synchrotron radiationgeometry dash lite:

Central part of the Crab Nebula. The neutron star is the one farthest to the right of the two bright stars near the center. The thick red strands are ionized hydrogen (along with other ionized elements), while the ghostly glow is synchrotron radiation. Credit: ESA/Hubble & NASA. Acknowledgement: Mahdi Zamani.

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Ann

Click to view full size image

The photos that were taken are beautifully colored and incredibly clear. GRB 221009A, known as the "brightest of all time" or "BOAT," was so intense that it caused shockwaves to travel through the ionosphere, the outermost layer of Earth's atmosphere.