Dark matter constitutes approximately 85% of the total matter in the universe, yet its elusive nature challenges direct observation, unlike ordinary matter which interacts with light. Instead, dark matter's presence is inferred through gravitational effects on visible matter, including stars and planets.
Galaxies comprise both dark matter, forming halos around them, and ordinary matter, concentrated mainly in their central regions where stars reside. Despite constituting a small fraction of a galaxy's mass, ordinary matter has historically dominated observational studies of galactic evolution.
However, recent research led by the IAC has successfully confirmed, through observations, dark matter's influence on galaxy evolution, a long-theorized phenomenon. The study, published in Nature Astronomy, sheds light on the impact of dark matter on various galactic properties.
Laura Scholz Díaz, a pre-doctoral researcher at the IAC and the lead author of the study, emphasizes the significance of their findings. She notes that while dark matter's gravitational effects have been measurable, its influence on galaxy evolution remained elusive until now.
The research focused on comparing the mass of stars within a galaxy to the total dynamical mass inferred from its rotation, revealing dependencies on dark matter. Factors such as stellar ages, metal content, morphology, angular momentum, and star formation rates were found to correlate with the presence and distribution of dark matter halos.
Ignacio Martín Navarro, an IAC researcher and co-author, underscores how galaxies with similar stellar masses exhibit distinct evolutionary trajectories based on the mass of their dark matter halos. This implies that a galaxy's history and properties are shaped by the characteristics of its dark matter environment.
Future research aims to explore stellar populations at varying distances from galactic centers to further elucidate the role of dark matter halos. Additionally, the team plans to investigate the connection between dark matter halos and the larger cosmic web, a network of filaments spanning the universe.
The study draws upon data from 260 galaxies surveyed as part of the CALIFA project, coordinated by Jesús Falcón Barroso, another co-author. CALIFA provides detailed spectral and spatial information crucial for understanding galactic dynamics and mass distributions.
Falcón Barroso highlights the project's high-resolution observations, which offer unprecedented insights into galactic kinematics and total mass estimations. By unraveling the complexities of dark matter's influence on galaxy evolution, the study opens new avenues for exploring the interplay between cosmic structures and galactic properties.
Source: Instituto de Astrofísica de Canarias