Free Astronomy Magazine September-October 2026

29 SEPTEMBER-OCTOBER 2026 ASTRO PUBLISHING has been magnified and dis- torted by the gravity of a massive foreground galaxy, splitting it into four sepa- rate images. By combining ALMA’s high-resolution data with gravitational-lens mod- eling, the research team re- constructed the galaxy’s true structure and probed the dense gas fueling its star- burst. Neutrinos are electrically neutral elementary particles that interact only weakly with matter. They can travel through gas, dust, and mag- netic fields almost unal- tered, carrying information directly from some of the most energetic environ- ments in the Universe. On September 22, 2021, Ice- Cube — embedded deep in the Antarctic ice — detected a high-energy neutrino e- vent designated IC 210922A, with an estimated energy of roughly 750 teraelectron- volts, far beyond what most known astronomical proc- esses can produce. Telescopes around the world searched the neutrino’s lo- calization region across the spectrum but found no con- vincing gamma-ray, X-ray, or optical transient to explain it. Follow-up observations with the James Clerk Max-well Telescope turned up an exceptionally bright submillimeter source within the re- gion. The Submillimeter Array re- fined its position, and ALMA then provided the resolution and spectral detail needed to determine its phys- ical nature. The team estimates the chance of finding such an unusually bright submillimeter galaxy at ran- dom within the IceCube localization region at roughly 1% or lower. That doesn’t establish a definitive physi- T his image shows a close-up of the gravitationally lensed galaxy nicknamed “Shadow Blaster,” which astronomers have identified as the likely source of the high-energy neu- trino event IC 210922A, detected by the IceCube Neutrino Observatory in 2021. In this case, a foreground galaxy, which is not visible in this image, is bending the light of the more distant Shadow Blaster galaxy, creating multiple distorted images of it that appear here as yellow arcs. [NOIRLab/NSF/AURA/ALMA (ESO/NAOJ/NRAO)] cal link, but the positional coinci- dence — combined with the ab- sence of any equally plausible alternative — makes Shadow Blaster the leading candidate coun- terpart in the field. ALMA observed Shadow Blaster in Bands 3, 4, and 5. Its highest-resolu- tion continuum data resolved the source into four distinct images arranged around a foreground el- liptical galaxy — the signature of strong gravitational lensing, in which the foreground galaxy’s grav- ity bends and magnifies light from the much more distant background source, acting as a natural cosmic telescope. Using the four lensed im- ages together with optical and in- frared data on the foreground gal-axy, the team modeled the lens- ing effect and reconstructed Shadow Blaster’s intrinsic appear- ance. The reconstruction revealed an extended star-forming region roughly 1,700 light-years across, alongside an even more compact, unresolved component. The magni-