A Giant Gamma-Ray Bubble is a Source of Extreme Cosmic Rays

An artist's depiction of a gamma-ray burst's relativistic jet full of very-high-energy photons breaking out of a collapsing star. Credit: DESY, Science Communication Lab

Gamma-ray bursts (GRBs) are one of the most powerful phenomena in the Universe and something that astronomers have been studying furiously to learn more about their origins. In recent years, astronomers have set new records for the most powerful GRB ever observed – this includes GRB 190114C, observed by the Hubble Space Telescope in 2019, and GRB 221009A, detected by the Gemini South telescope in 2022. The same is true for high-energy cosmic rays that originate from within the Milky Way, whose origins are still not fully understood.

In a recent study, members of China’s Large High Altitude Air Shower Observatory (LHAASO) Collaboration discovered a massive gamma-ray burst (designated GRB 221009A) in the Cygnus star-forming region that was more powerful than 10 peta-electronvolts (PeV, 1PeV=1015eV), over ten times the average. In addition to being the brightest GRB studied to date, the team was able to precisely measure the energy spectrum of the burst, making this the first time astronomers have traced cosmic rays with this energy level back to their source.

Continue reading “A Giant Gamma-Ray Bubble is a Source of Extreme Cosmic Rays”

ESA Has a Difficult Choice: Study Mars, Earth's Magnetosphere, or Gamma-Ray Bursts

The space science community has narrowed down the shortlist for ESA’s next ‘medium’ mission to three finalists: M-Matisse, Plasma Observatory and Theseus. Credit: ESA

The European Space Agency (ESA) is looking to the future and contemplating its next M-class (Medium) mission. These missions are crucial to the ESA Science Programme (part of the agency’s Science Directorate), which aims to provide the best tools to ensure Europe’s continued participation in space exploration and sustain its capabilities in space by fostering innovation, maintaining launch services, and spacecraft operations. The latest round began in December 2021, when the ESA called for proposals for the next M-class mission to launch in the mid-2030s.

In a statement issued yesterday (Wednesday, November 8th), the ESA announced that it had narrowed the list of candidates to three concepts. These include the twin M-MATISSE, the seven-spacecraft Plasma Observatory, and the THESEUS satellite. The final selection will assist ESA operations and research in space by studying the evolution and past habitability of Mars, exploring the plasma environment around Earth, or studying powerful transient events across the Universe. The final selection of one mission is expected to happen by mid-2026.

Continue reading “ESA Has a Difficult Choice: Study Mars, Earth's Magnetosphere, or Gamma-Ray Bursts”

What’s the Link Between Gamma Ray Bursts and Supernovae? It Might Be Binary Stars

Gamma-ray bursts (GRBs) are some of the most violent events in the universe. Some have a power output equivalent to all of the other stars in the observable universe, at least in the spectrum of gamma rays. But we know very little about them. A new paper from researchers on an interdisciplinary team from seven countries puts forth a new theory about how at least one type of GRB happens – when a binary of two specific types of stars collapses and forms a black hole.

Continue reading “What’s the Link Between Gamma Ray Bursts and Supernovae? It Might Be Binary Stars”

Beyond “Fermi’s Paradox” X: What is the Firstborn Hypothesis?

Artist's impression of an exoplanet orbiting a low-mass star. Credit: ESO/L. Calçada

Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that the reason for the Great Silence is that we are “early to the party”!

In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?

This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Since Fermi’s time, there have been several proposed resolutions to his question, which includes the Firstborn Hypothesis that states that humanity could be the first intelligent life to emerge in our galaxy.

Continue reading “Beyond “Fermi’s Paradox” X: What is the Firstborn Hypothesis?”

It Takes Two Stars to Make a Gamma Ray Burst

Artist’s impression of gamma-ray burst with orbiting binary star. Credit: University of Warwick/Mark Garlick

In 1967, NASA scientists noticed something they had never seen before coming from deep space. In what has come to be known as the “Vela Incident“, multiple satellites registered a Gamma-Ray Burst (GRB) that was so bright, it briefly outshined the entire galaxy. Given their awesome power and the short-lived nature, astronomers have been eager to determine how and why these bursts take place.

Decades of observation have led to the conclusion that these explosions occur when a massive star goes supernova, but astronomers were still unsure why it happened in some cases and not others. Thanks to new research by a team from the University of Warwick, it appears that the key to producing GRBs lies with binary star systems – i.e. a star needs a companion in order to produce the brightest explosion in the Universe.

Continue reading “It Takes Two Stars to Make a Gamma Ray Burst”

Massive Triple Star System Creates this Bizarre Swirling Pinwheel of Dust. And it Could be the Site of a Gamma Ray Burst

The VISIR instrument on ESO’s VLT captured this stunning image of a newly-discovered massive binary star system. Nicknamed Apep after an ancient Egyptian deity, it could be the first gamma-ray burst progenitor to be found in our galaxy. Apep’s stellar winds have created the dust cloud surrounding the system, which consists of a binary star with a fainter companion. With 2 Wolf-Rayet stars orbiting each other in the binary, the serpentine swirls surrounding Apep are formed by the collision of two sets of powerful stellar winds, which create the spectacular dust plumes seen in the image. The reddish pinwheel in this image is data from the VISIR instrument on ESO’s Very Large Telescope (VLT), and shows the spectacular plumes of dust surrounding Apep. The blue sources at the centre of the image are a triple star system — which consists of a binary star system and a companion single star bound together by gravity. Though only two star-like objects are visible in the image, the lower source is in fact an unresolved binary Wolf-Rayet star. The triple star system was captured by the NACO adaptive optics instrument on the VLT. Credit: ESO/Callingham et al.

When stars reach the end of their lifespan, many undergo gravitational collapse and explode into a supernova, In some cases, they collapse to become black holes and release a tremendous amount of energy in a short amount of time. These are what is known as gamma-ray bursts (GRBs), and they are one of the most powerful events in the known Universe.

Recently, an international team of astronomers was able to capture an image  of a newly-discovered triple star system surrounded by a “pinwheel” of dust. This system, nicknamed “Apep”, is located roughly 8,000 light years from Earth and destined to become a long-duration GRB. In addition, it is the first of its kind to be discovered in our galaxy.

Continue reading “Massive Triple Star System Creates this Bizarre Swirling Pinwheel of Dust. And it Could be the Site of a Gamma Ray Burst”

A Gamma-Ray Burst as Music

This is awesome.

What would a gamma-ray burst sound like? No one really knows, but members of the team that work with the Fermi Large Area Telescope (LAT) have translated gamma-ray measurements into musical notes and have created a “song” from the photons from one of the most energetic of these powerful explosions, GRB 080916C which occurred in September of 2008.

“In translating the gamma-ray measurements into musical notes we assigned the photons to be “played” by different instruments (harp, cello, or piano) based on the probabilities that they came from the burst,” the team wrote in the Fermi blog. “By converting gamma rays into musical notes, we have a new way of representing the data and listening to the universe.”
Continue reading “A Gamma-Ray Burst as Music”