A new ultra-detailed map of the Sculptor Galaxy exposes stellar life and hidden structures, offering new insights into how small-scale processes influence entire galaxies.
Astronomers have unveiled a remarkable new view of the Sculptor Galaxy, producing a highly detailed image that exposes features never seen before. The achievement comes from observations with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), which captured the galaxy in thousands of different colors at once. By gathering enormous amounts of data from every region, the team assembled a complete picture of how stars live and evolve across Sculptor.
“Galaxies are incredibly complex systems that we are still struggling to understand,” says ESO researcher Enrico Congiu, who led a new Astronomy & Astrophysics study on Sculptor. Reaching hundreds of thousands of light-years across, galaxies are extremely large, but their evolution depends on what’s happening at much smaller scales. “The Sculptor Galaxy is in a sweet spot,” says Congiu. “It is close enough that we can resolve its internal structure and study its building blocks with incredible detail, but at the same time, big enough that we can still see it as a whole system.”
The building blocks of a galaxy, which include stars, gas, and dust, shine in different colors of light. The more distinct colors captured in an image, the deeper the insight into a galaxy’s inner processes. Standard images usually display only a few colors, but the new map of Sculptor contains thousands. With this level of detail, astronomers can determine properties of the stars, gas, and dust such as their age, chemical composition, and movements.
To create this map of the Sculptor Galaxy, which is 11 million light-years away and is also known as NGC 253, the researchers observed it for over 50 hours with the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s VLT. The team had to stitch together over 100 exposures to cover an area of the galaxy about 65 000 light-years wide.
A Tool for Zooming In and Out
According to co-author Kathryn Kreckel from Heidelberg University, Germany, this makes the map a potent tool: “We can zoom in to study individual regions where stars form at nearly the scale of individual stars, but we can also zoom out to study the galaxy as a whole.”
In their first analysis of the data, the team uncovered around 500 planetary nebulae, regions of gas and dust cast off from dying Sun-like stars, in the Sculptor Galaxy. Co-author Fabian Scheuermann, a doctoral student at Heidelberg University, puts this number into context: “Beyond our galactic neighbourhood, we usually deal with fewer than 100 detections per galaxy.”
Because of the properties of planetary nebulae, they can be used as distance markers to their host galaxies. “Finding the planetary nebulae allows us to verify the distance to the galaxy — a critical piece of information on which the rest of the studies of the galaxy depend,” says Adam Leroy, a professor at The Ohio State University, USA, and study co-author.
Future projects using the map will explore how gas flows, changes its composition, and forms stars all across this galaxy. “How such small processes can have such a big impact on a galaxy whose entire size is thousands of times bigger is still a mystery,” says Congiu.
Reference: “The MUSE view of the Sculptor galaxy: Survey overview and the luminosity function of planetary nebulae” by E. Congiu, F. Scheuermann, K. Kreckel, A. Leroy, E. Emsellem, F. Belfiore, J. Hartke, G. Anand, O. V. Egorov, B. Groves, T. Kravtsov, D. Thilker, C. Tovo, F. Bigiel, G. A. Blanc, A. D. Bolatto, S. A. Cronin, D. A. Dale, R. McClain, J. E. Méndez-Delgado, E. K. Oakes, R. S. Klessen, E. Schinnerer and T. G. Williams, 12 August 2025, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202554144
Never miss a breakthrough: Join the SciTechDaily newsletter.