Astronomers have completed a massive panoramic picture of the Andromeda Galaxy, showcasing its turbulent history and providing new insights into the structure and evolution of our own Milky Way galaxy. The 2.5-billion-pixel mosaic combines data from over 600 Hubble Space Telescope snapshots taken over more than a decade.
The Andromeda Galaxy is the closest large galaxy to the Milky Way, at a distance of 2.5 million light years away, and its size rivals that of our own galaxy. The panoramic picture reveals stars moving at incredible speeds, some with velocities exceeding 200 km/s, allowing astronomers to understand the galaxy’s rotation and movement patterns.
Researchers from UC Santa Cruz played a key role in the effort, using data from the Deep Extragalactic Imaging Multi-Object Spectrograph (DEIMOS) at the W.M. Keck Observatory to study the stars’ velocities and characteristics. This data set is transforming our understanding of how Milky Way-like galaxies form and evolve.
The galaxy’s unique features, including a large central bulge of older stars and a star-forming disk that’s not as active as expected, suggest it may have undergone a collision with another galaxy in the past. Computer simulations indicate that such an encounter could lead to a decline in star formation, resulting in the galaxy’s observed characteristics.
The Andromeda Galaxy is often referred to as M31 due to its listing in the Messier Catalog as the 31st object. The panoramic picture offers a unique window into this galaxy’s history and evolution, providing valuable insights for astronomers studying our own Milky Way’s structure and development.
Source: https://news.ucsc.edu/2025/01/andromeda-galaxy-mosaic.html