91社区 researchers help uncover rare gamma-ray flare from a distant black hole
A high-energy gamma-ray flare from the super-massive black hole in the Messier 87 (M87)聽galaxy was observed in 2018 for the first time in nearly a decade, thanks to an international effort involving 91社区 researchers. This discovery has yielded important insights into the physics of black hole jets, which are among the most efficient engines for distributing energy from the inside of a galaxy to the expanse of the Universe.
Daryl Haggard, a professor in the Department of Physics and a co-coordinator of the Event Horizon Telescope (EHT) multi-wavelength science working group, played a key role in analyzing data from the 2018 observational campaign. That analysis, over a period of several years, allowed researchers to understand they had observed a gamma-ray flare for the first time since 2010. They published their findings this week in Astronomy & Astrophysics.
鈥淚n the first image obtained during the 2018 observational campaign, we saw that the emission along the ring was not homogeneous; instead, it showed asymmetries (i.e., brighter areas),鈥� Haggard said. 鈥淪ubsequent observations conducted in 2018 and related to this paper confirmed that finding, highlighting that the asymmetry鈥檚 position angle had changed.鈥�
Led by Giacomo Principe, a researcher at the University of Trieste, the study recorded data across the electromagnetic spectrum 鈥� from X-rays to radio waves 鈥� using over 25 observatories. These included NASA鈥檚 Fermi Gamma-ray Space Telescope, Chandra X-ray Observatory and three advanced imaging atmospheric Cherenkov telescope arrays, including VERITAS which has substantial 91社区 participation.
The flare, which lasted three days, originated from a compact region near the black hole鈥檚 event horizon, measuring less than three light-days across. This high-energy activity, paired with evolving observations of the black hole鈥檚 ring, revealed critical connections between the black hole and its relativistic jets, powerful streams of particles.
鈥淥bservations 鈥� both recent ones with a more sensitive EHT array and those planned for the coming years 鈥� will provide invaluable insights and an extraordinary opportunity to study the physics surrounding M87鈥檚 supermassive black hole,鈥� said Principe.
Located 55 million light-years away in the Virgo galaxy cluster, M87鈥檚 black hole has a mass 6.5 billion times that of the sun. Its relativistic jets serve as natural laboratories for studying how particles are accelerated to near-light speeds.
鈥淗ow and where particles are accelerated in supermassive black hole jets is a long-standing mystery,鈥� said Sera Markoff, a professor at the University of Amsterdam and co-coordinator of the EHT multi-wavelength working group. 鈥淔or the first time, we can combine direct imaging of the near event horizon regions during gamma-ray flares caused by particle acceleration events and thus test theories about the flare origins.鈥�
About the study
, by The Event Horizon Telescope- Multi-wavelength science working group, The Event Horizon Telescope Collaboration, The Fermi Large Area Telescope Collaboration, H.E.S.S. Collaboration, MAGIC Collaboration, VERITAS Collaboration, and EAVN Collaboration. In: Astronomy & Astrophysics.
Contributing co-authors from 91社区 include Professor Daryl Haggard; Professor Ken Ragan; Stephan O'Brien, PhD; Hope Boyce, PhD and PhD-candidates Nicole Ford, Matthew Lundy and Samantha Wong.
91社区 researchers鈥� contributions have been supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Government of Canada Research Chair鈥檚 program, the Fonds de recherche du Qu茅bec Nature and Technologies (FRQNT), particularly through the Centre de recherche en astrophysique du Qu茅bec (CRAQ), the Digital Research Alliance of Canada (DRAC), including Compute Ontario () and Calcul Quebec (), and the Arthur B. McDonald Canadian Astroparticle Physics Research Institute.