An international team of astronomers from the Shanghai Astronomical Observatory of the Chinese Academy of Sciences and Westlake University has developed a novel galaxy "dissection" technique that enables precise analysis of the distinct components within barred spiral galaxies. 

The findings, published in Astronomy & Astrophysics, open a new window into understanding the formation and evolution of galaxies in the universe.

Barred spiral galaxies are a common type of galaxy characterized by a central bar-like structure—with our own Milky Way as a prime example. However, due to observational limitations, scientists have struggled to comprehensively study their internal structures. The central regions of barred galaxies could comprise multiple structures with diverse physical origins, which is hard to separate through traditional methods.

This new method works like a "CT scan" for galaxies. By analyzing the motion and chemical composition of stars, the researchers decomposed barred spirals into four main components: the central bar (often exhibiting a "peanut-shaped" morphology), the bulge region, the rotating thin disk, and the diffuse stellar halo.

To validate the method, the researchers employed supercomputers to model 12 sets of mock observational data of galaxies from different viewing angles. The results demonstrated that their approach accurately measures the mass distribution of each component with errors below 15%. Additionally, they reconstructed the "age records" and chemical compositions of stars in different regions, providing crucial clues about galaxy evolution.

"It's like studying Earth's history through fossils," said ZHU Ling, co-author of the study. "Stars in different regions preserve information about the galaxy's formation at different epochs. The bar is typically younger, while the bulge and halo consist of much older stars."

This structural decomposition of barred spirals is a key point in the team's ongoing work on dynamical modeling, successfully separating the classical bulge and bar structures— a challenge in previous studies.

This study will help astronomers delve deeper into the evolutionary history of barred spiral galaxies like the Milky Way. In the future, the researchers plan to apply this method to real observational data, particularly targeting galaxy samples from the European Southern Observatory's GECKOS survey.