Rubin Observatory’s First light Reveals Unexpected Stellar Stream Behind Galaxy M61
Chile – In a stunning early result, the Vera C. Rubin Observatory has detected a previously unseen stellar stream trailing the iconic galaxy Messier 61, hinting at a past galactic collision and demonstrating the observatory’s potential to reshape our understanding of cosmic history. The discovery was made while examining the observatory’s first test image, even before the commencement of its official scientific survey.
“This is the first stellar stream detected from Rubin,” says Sarah Pearson, an astrophysicist at the University of Copenhagen. “And it’s just a precursor for all of the many, many features we’ll find like this.” The findings have been reported in the Research Notes of the American Astronomical Society1.
Messier 61, first observed in 1779 within the Virgo Cluster, is a well-studied “starburst galaxy” known for its high rate of star formation and frequent supernovae. Despite extensive observation with powerful telescopes like the James Webb and Hubble Space Telescopes, the stellar stream remained undetected until now.
“Despite all of this intense study, no one had ever found this stellar stream,” says Aaron Romanowsky, an astronomer at San Jose state University in California and a co-author of the study. The newly discovered stream suggests that Messier 61 gravitationally disrupted and absorbed a smaller galaxy, leaving behind a trail of stars.
1 Research Notes of the American Astronomical Society.
