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New Observations Reveal the Staggering Scale of the Universe’s Largest Galaxy
The Debrief • • science
Key Points:
- New ultra-deep images of IC 1101 confirm it as the largest known galaxy, spanning roughly 1.7 million light-years and containing an estimated 3.4 trillion solar masses of stars, far surpassing the Milky Way in size and mass.
- IC 1101 is a brightest cluster galaxy (BCG) that has grown by absorbing smaller neighboring galaxies over billions of years, resulting in faint, diffuse outer regions that blend into the surrounding galaxy cluster.
- Researchers overcame challenges from scattered light caused by foreground stars by modeling and subtracting this interference, allowing unprecedented detail in observing IC 1101’s faint outer boundaries.
- Evidence suggests IC 1101 is still growing, with detected structures beyond its main edge and signs of past collisions with other galaxy groups that continue to influence its development.
- The study, led by Carlos Marrero-de la Rosa, is published in preprint form on arXiv and will appear in Astronomy and Astrophysics, providing new insights into the maximum scale galaxies can achieve.
