In October 2022, the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory detected an extraordinarily powerful Gamma Ray Burst (GRB). It still stands as the Brightest Of All Time (BOAT), and astronomers have been curious about it ever since.
New research has uncovered more details in the burst. What do they tell us about these forceful explosions?
“When I first saw that signal, it gave me goosebumps.”
Maria Edvige Ravasio, Radboud University, Nijmegen, NetherlandsGRBs are the most powerful energetic events in the Universe, second only to the Big Bang. They’re brief yet powerful explosions that can release as much energy in a few seconds as the Sun will release in its billions of years of fusion. Astronomers don’t completely understand the mechanism behind them. They seem to come from the explosion of an extremely massive star or the merger of two extremely dense objects like neutron stars or black holes.
A GRB’s initial burst is called the prompt emission. While the prompt emissions themselves last anywhere from milliseconds to several hundred seconds, GRBs have afterglows that are much longer-lived and emitted in wavelengths longer than gamma rays: X-ray, ultraviolet, optical, infrared, microwave, and radio emissions. This means that astronomers can still study their source long after the gamma rays have disappeared.
When BOAT, aka GRB 221009A, was discovered, it was so powerful that it saturated Fermi’s detectors. That means astronomers weren’t able to observe some of the GRB’s most energetic moments.
In new research published in Science, astronomers say they’ve found another peak in GRB 221009A’s prompt emissions data. The research is “A mega–electron volt emission line in the spectrum of a gamma-ray burst.” The lead author is Maria Edvige Ravasio, a Post-doctoral Researcher in Astrophysics at Radboud University in Nijmegen, Netherlands. This peak is a new clue about what happens during a GRB.
“The physics of the prompt emission is poorly understood: The dominant form of energy in the relativistic jet is unknown, as is the nature of the radiative process responsible for producing the observed photons,” the authors write in their paper.
In their new research, the team used observations of the GRB and combined them with statistical models to identify new features. They divided the GRB into different time intervals and analyzed them separately and together. They focused on the parts of the prompt emission that weren’t the brightest. “We investigated the less bright portions of the prompt emission,” they write, and they avoided the portion of the signal that was saturated by the GRB’s extraordinary power.
This figure from the research shows some of the analysis. The horizontal axis shows the time since the GBM. GBM is the Gamma-ray Burst Monitor, an instrument on the Fermi Space Telescope that’s triggered by GRBs. The vertical axis shows the count rate, the blue line is the GRB’s light curve, and the numbered segments are the thirteen time intervals the researchers worked with. The grey area labelled BTI stands for Bad Timing Interval, excluded because the detector was saturated by the BOAT’s overwhelming energy. Image Credit: Ravasio et al. 2024.“A few minutes after the BOAT erupted, Fermi’s Gamma-ray Burst Monitor recorded an unusual energy peak that caught our attention,” said Ravasio. “When I first saw that signal, it gave me goosebumps. Our analysis since then shows it to be the first high-confidence emission line ever seen in 50 years of studying GRBs.” A high-confidence emission line is a specific wavelength of light that’s unlikely to be noise. Like everything else about GRBs, the line was transient. It only lasted 40 seconds, but it’s still significant. It occurred about five minutes after the initial burst and peaked at 12 MeV (million electron volts). To put that into context, the light our eyes can sense, called visible light, ranges from only two to three eV.
This figure from the research shows some of the results. The left panel is for the 290 to 295-second interval, and the right panel is for the 300 to 320-second interval. These panels are dense with information, but the main takeaway is the peak shown with black dotted lines in both panels. “We find that the spectra at times 280 to 320 s after the GBM trigger contain a narrow emission feature at ~10 MeV,” the authors write. They used different models and methods to understand the data. SBPL stands for “smoothly-broken power law,” and Gaussian is another data handling method. Image Credit: Ravasio et al. 2024.The newfound emission line is significant because of what happens to the energy emitted by GRBs. When powerful electromagnetic radiation collides with matter, it can be absorbed and then re-emitted at lower wavelengths. Depending on conditions, some wavelengths of light will be more prominent than others. Astronomers examine the light spectroscopically, and depending on the light that’s prominent or obscured, they can learn a lot about the chemistry of the matter that’s emitting the light. Some of the features in the spectrum can also reveal particle processes that are occurring. One of those processes is the annihilation of matter and anti-matter.
When astronomers studied the absorption and emission spectra from GRBs in the past, they couldn’t be certain that what they were seeing wasn’t noise. But this time, it’s different.
“We’ve determined that the odds this feature is just a noise fluctuation are less than one chance in half a billion.”
Om Sharan Salafiam co-author, INAF-Brera Observatory in Milan, Italy“While some previous studies have reported possible evidence for absorption and emission features in other GRBs, subsequent scrutiny revealed that all of these could just be statistical fluctuations. What we see in the BOAT is different,” said coauthor Om Sharan Salafia at INAF-Brera Observatory in Milan, Italy. “We’ve determined that the odds this feature is just a noise fluctuation are less than one chance in half a billion.”
The researchers think that the emission line comes from gamma rays travelling at nearly the speed of light. Their most likely source is exotic: the annihilation of matter and anti-matter.
“When an electron and a positron collide, they annihilate, producing a pair of gamma rays with an energy of 0.511 MeV,” said coauthor Gor Oganesyan at Gran Sasso Science Institute and Gran Sasso National Laboratory in L’Aquila, Italy. “Because we’re looking into the jet, where matter is moving at near light speed, this emission becomes greatly blueshifted and pushed toward much higher energies.”
For the observed peak to reach the 12 MeV level, the electrons and positrons had to be moving at 99.9 % of the speed of light: 299,492,665 meters per second.
This artist’s illustration shows a jet of particles moving at nearly light speed emerging from a massive star. When the star ran out of fuel, it collapsed into a black hole. The black hole’s powerful gravity drew nearby matter toward it, and some of the matter was redirected into dual jets firing in opposite directions. We see a gamma-ray burst when one of these jets happens to point directly at Earth. Image Credit: NASA’s Goddard Space Flight Center Conceptual Image LabThis emission line is a new window into the world of powerful GRBs.
“After decades of studying these incredible cosmic explosions, we still don’t understand the details of how these jets work,” said Elizabeth Hays, the Fermi project scientist at NASA’s Goddard Space Flight Center. “Finding clues like this remarkable emission line will help scientists investigate this extreme environment more deeply.”
The post Astronomers Uncover New Details in the Brightest Gamma Ray Burst Ever Detected appeared first on Universe Today.
This link was sent to me by a despondent (and of course anonymous) New Zealander with the comment, “This is now unstoppable in NZ.” It’s from the Times Higher Education site, and the authors are Mahdis Azarmandi and Sara Tolbert, both on the Faculty of Education of New Zealand’s University of Canterbury.
Click screenshot to read:
It’s fairly clear that by full “decolonization,” the authors propose a full disruption and subversion—yes, they use those words—of universities, with the ideal being to give the lands and waters back to the Māori people, as well as completely transforming college education into a program catering to the indigenous people. I’ll give the authors’ intentions, and then show their “praxis” for decolonization. Excerpts are indented and bolding is mine.
As non-Indigenous scholars, we can engage in anticolonial and feminist practices that subvert the settler colonial university, but we cannot promise “decolonisation”, especially in a country such as New Zealand, where the effects of colonisation are ongoing and where, in the words of Indigenous climate activist India Logan-Riley, “land back, oceans back” is yet to be realised. Unless the university is fully engaged in land back, oceans back, decolonisation will be used by the settler colonial university to justify settler occupation of stolen land, water and knowledge (see “additional links”, below).
Rather than offer how-to tips for “decolonising the university”, we suggest a few points as a call for collective action to change things that are unjust – inside and outside the university. We argue that to engage in anticolonial, feminist practice, we must address the systems that produce violence and exploitation, not just in the scholarly aspect of our work but also within our own institutional and material conditions such as housing, jobs and access to health. Some of these points are taken from our forthcoming chapter “A manifesto for transdisciplinary (transgressive) feminist praxis in the Academy”.
It’s clear from these words that the authors, who are both non-indigenous, don’t want merely a cosmetic redo of universities, which they see as not only having stolen the land and water from the indigenous people, but also “produce violence and exploitation.” They mean what they say: they want a complete rethink and redo of how the country’s universities are run and what they teach.
Unless by “violence” the authors mean “offense”, the hyperbole is strong, especially since New Zealand’s government and universities are doing everything that can to create equity for the Māori. (Indigenous people constitute 16.5% of New Zealand, just ahead of the 15.1% Asian and well behind the 70% European people.) One question underlying all this is whether the whole system has to be transformed to cater to the people who got to the islands first. But I’ll leave that aside and move on, because it’s worth seeing the reforms these two scholars suggest. There are six alterations of “praxis”:
1.) We can’t both love and change the university at the same time. We must actively engage in the disruption of oppressive, settler colonial and patriarchal practices. Learning from abolitionist struggles, we need to engage in non-reformist reform – that is, practices that improve the lives and conditions of those most marginalised (outside and inside the university) but that do not consolidate the power of the institution.
By “most marginalized,” I presume they mean the Māori people, though later they pull others into the reformist tent. Note that their purpose is not education, but social reform—outside as well as inside the university. There is not a word about what sort of education people will get, save that it’s going to be centered on indigenous “ways of knowing”:
2.) A crucial aspect of anticolonial praxis in the university is recognising and respecting Indigenous epistemologies and, where possible, engaging these as central to its curriculum while also peripheralising European and settler knowledge, which has been foundational in its formation. However, how and to what extent Indigenous knowledge should be in the university is not for non-Indigenous people to decide, but the way we act within our natural and knowledge environment must not be extractivist. We can and must resist extracting resources and knowledge from land, water and people. We need also remember that some knowledge is not ours to share; “sometimes the knowledge does not need to be moved out of the communities where it resides into the pages, websites and walls of the academic industrial complex” (Tolbert & Azarmandi, forthcoming). What anticolonial feminist praxis centres is being-in-relation (with place and people). We need to approach the incorporation of Indigenous knowledge with humility – there is a fine line between incorporation of Indigenous knowledge and cultural appropriation. What we can do is make space by disrupting disciplinary boundaries and challenging the limitations of academic disciplines that discourage collaboration and maintain competition.
Here we see that the “settler colonialists”—that is, able-bodied heterosexual males of European descent (see below)—should have no say in what passes for knowledge in the university. Indigenous knowledge must be central, and settler knowledge peripheral. In practice, this means the Māorization of the entire curriculum, including science.
3.) We must build collaborative partnerships and alliances with other marginalised communities, acknowledging the intersections of colonialism, racism, sexism, homo-transphobia, ableism and other forms of oppression. Building genuine relationships and collaborative partnerships with Indigenous and marginalised communities is essential. If these relationships benefit scholars and the academy more than the community, chances are they are meant to further empower settler colonial regimes and not disrupt and decolonise them. Adapt feminist and collaborative writing practices; refuse symbolic service requests and instead strategise and work towards systemic change: unionise, organise for a living wage and improve institutional practices such as parental leave and access to healthcare and housing.
In the above they pull into their tent everyone considered marginalized, including the disabled, people of color, women, gay people, and trans people. It’s not just that these people deserve equal rights and equal educational opportunities—something that nobody would oppose—but that they will also participate in overthrowing and subverting the violent and exploitative universities. As for parental leave, healthcare and the like, that is the responsibility not of the universities themselves, but of the New Zealand government, which funds the universities.
4.) Anticolonial praxis requires institutional transformation at all levels. This also means securing the right to education and making sure public universities exist and are supported. In the institution, we need to critically examine and restructure policies, procedures and practices that perpetuate settler colonial regimes of power. It involves addressing systemic barriers that maintain inequality, such as access to education, hiring practices, tenure and promotion criteria, curricular decisions and funding allocations. Resist symbolic change and cultural window dressing. Name it; make it explicit.
#4 is more of the same, expressing a deep animus towards the “settler colonial regimes of power”, something they never give examples of. They also argue that “systemic barriers” (i.e., codified systems of bigotry) must be dismantled, although they give no examples of such barriers and I know of none.
5.) Anticolonial and feminist praxis requires constant self-reflection and a commitment to unlearning. It involves critically examining our own complicity within the settler colonial structures. Be mindful, however, that this reflective and personal work alone does not create change – and sometimes, as feminist scholar Sara Ahmed has illuminated, it can become another way of not doing things with words. Connect, resist and organise.
6.) Finally, we must dare to dream beyond the university. What if the university can’t be unsettled or decolonised? If we do unsettle or decolonise the institution, will it be recognisable once we are done? As la paperson (the avatar of K. Wayne Yang, an associate professor of ethnic studies at the University of California, San Diego) has written (and we cite in our forthcoming chapter), we should understand “the university as a machine that is the composite of many other [disloyal] machines” – ones that ‘break down and travel in unexpected lines of flight – flights that are at once enabled by the university yet irreverent of that mothership of a machine’. May we find each other…beyond the university, and unite in our irreverent lines of flight”.
Here the universities are seen as mere staging areas for society-wide transformation, something they implied when they said, “Building genuine relationships and collaborative partnerships with Indigenous and marginalised communities is essential. If these relationships benefit scholars and the academy more than the community, chances are they are meant to further empower settler colonial regimes and not disrupt and decolonise them.”
One gets the impression here that the writers would be happiest if all the Europeans (save the marginalized ones, like the gays or people of color, were heaved out of the country so it would revert to a system of Māori governance. Now it’s true that the Māori were historically oppressed, but were also given the rights of “colonialist” settlers as well as the right to keep all their lands and properties by the 1840 Treaty of Waitangi. This treaty, which is ambiguous and wasn’t even signed by all the indigenous leaders, is a holy document in New Zealand, interpreted by locals to mean that they get most of everything (the fearful Europeans dare not say otherwise).
When you read something like this, you wonder about not only the philosophy of Times Higher Education, which decided to print what is largely an incoherent (and incorrect) set of assertions and accusations, but you also wonder about what will happen to New Zealand. The authors, after all, are “settler-colonialists”, calling for their own decimation.
What is happening in New Zealand—with all the many official attempts to create equity only serving to provoke tirades like the one above—is the world’s most far-reaching attempt at ideological capture of an entire country by the people who consider themselves entitled to run the whole country: the descendants of the original Polynesian settlers. But the world has moved on, and who can deny that “settler colonialists”, by bringing with them their knowledge, medicines, free national healthcare, and inventions, have improved the lives of most people in New Zealand? It is not as if the arrival of people from elsewhere has been an unmitigated evil.
I think the person who sent me this screed is right: this movement is unstoppable, and it’s going to ruin New Zealand. Apparently the Luxon government is either ignoring this stuff or doesn’t care to stop it. Soon it will be too late, if it isn’t already.
I pity New Zealanders who want to get a good college education in the face of people like Drs. Azarmandi and Tolbert, whose program will sink New Zealand to the bottom of the academic ranking of comparable countries.