Using the deepest images ever taken, researchers have traced the outer edge of the galaxy IC 1101, yielding the first direct measurement of its full size.
The data indicate a diameter of roughly 520 kiloparsecs, equivalent to about 1.7 million light‑years, which exceeds all previously known systems and currently ranks IC 1101 as the largest observed galaxy in the universe.
In addition to its size, the stellar mass is estimated at approximately 3.4 trillion solar masses, derived from the brightness and light distribution in the faint outer regions that were previously undetectable.
The findings were posted as a preprint on July 16 to the arXiv server and will serve as a basis for further investigations into the formation and evolution of extremely massive galaxies. Scientists anticipate that comparable observations of other candidates will clarify the upper limits of galactic growth processes.