The leaking star cluster
Peer-Reviewed Publication
In honor of Global Astronomy Month, we’re exploring the science of space. Learn how astronomy connects us through curiosity, discovery, and a shared wonder for what lies beyond.
Updates every hour. Last Updated: 12-Dec-2025 15:11 ET (12-Dec-2025 20:11 GMT/UTC)
Astronomers combined data from two major gamma-ray observatories with further multi-wavelength information to reveal a “nascent outflow” from the most massive young star cluster in the Milky Way, Westerlund 1.
The observations indicate that charged particles – “cosmic rays” – are accelerated in the vicinity of the star cluster and subsequently transported along the outflow.
The nascent outflow is expected to eventually develop into a channel for the transport of cosmic rays into the Galactic halo – a process widely assumed of great importance for galaxy evolution, but with scarce observational support so far.
Leading X-ray space telescopes XMM-Newton and XRISM have spotted a never-seen-before blast from a supermassive black hole. In a matter of hours, the gravitational monster whipped up powerful winds, flinging material out into space at eye-watering speeds of 60 000 km per second.
Astronomers have observed the longest-ever gamma-ray burst — a powerful, extragalactic explosion that lasted over seven hours. Rapid follow-up observations with the U.S. Department of Energy-fabricated Dark Energy Camera and the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab, provided crucial information about the possible origin of this extraordinary event and the galaxy that hosts it.