First-Ever Image of Black Hole Reveals Unexpected Gamma-Ray Burst
In 2018, scientists revealed a groundbreaking achievement: the first-ever image of a black hole, captured by the Earth-sized Event Horizon Telescope (EHT). Now, that same black hole, known as M87*, has stunned researchers again, erupting with an unexpected and powerful gamma-ray flare. This surprising event offers new opportunities to explore the dynamics surrounding supermassive black holes and test our understanding of astrophysics.
The flare occurred between April and May 2018, lasting about three days, and originated from M87*, the supermassive black hole located 55 million light-years away at the heart of the M87 galaxy. Using a network of 25 ground-based and space-based telescopes, the EHT detected the event as high-energy gamma rays, marking the most energetic eruption observed from M87* since 2010.
Supermassive black holes, which are believed to reside at the centers of all large galaxies—including our Milky Way—differ in size and behavior. For comparison, M87* has a staggering mass of 5.4 billion suns, while our Milky Way’s Sagittarius A* (Sgr A*) weighs in at just 4.3 million suns. Unlike Sgr A*, which has a relatively sparse diet, M87* is actively feeding on its surroundings, fueling the jets and flares detected by instruments like the EHT.
A Messy Cosmic Eater
While supermassive black holes are often imagined as insatiable cosmic vacuum cleaners, M87* is surprisingly inefficient. Most of the material in its accretion disk—a swirling cloud of plasma and gas—never reaches the black hole. Instead, powerful magnetic fields accelerate particles to near-light speeds, blasting them outward as massive, high-energy jets.
The recent gamma-ray flare revealed that these jets extend to astonishing distances, tens of millions of times wider than the black hole itself. For scale, it’s equivalent to a blue whale erupting from a single bacterium. How black holes generate such jets remains a major astrophysical mystery, one the EHT hopes to solve.
The Role of Collaboration
The EHT’s success in detecting and analyzing this flare stems from global collaboration. In addition to its Earth-based observatories, data from space telescopes like Fermi, NuSTAR, Chandra, and Swift played a key role. This multi-wavelength approach enabled scientists to identify changes in the jet’s direction and brightness, as well as subtle shifts in the black hole’s event horizon—the light-trapping boundary surrounding it.
Giacomo Principe, project leader from the University of Trieste, emphasized the significance of these observations:
“These results offer the first-ever chance to identify the point at which particles causing the flare are accelerated. This could resolve long-standing questions about the origin of cosmic rays and the mechanisms powering black hole jets.”
The coordinated effort underscores the importance of observing cosmic phenomena across the electromagnetic spectrum. Insights from M87* continue to deepen our understanding of black holes and their powerful influence on the surrounding universe.
