Oral Presentation
Galaxy Manifold: A Unification of Observed Galaxy Properties
Presenter: Suchetha Cooray (Nagoya University)
Galaxy evolution is a complicated process that encompasses many physical properties in/around a galaxy (e.g., stellar mass, gas mass, star formation rates, star formation histories, environment). Observational studies have discovered many galaxy scaling laws, such as the star formation main sequence, Tully-Fisher relation, and Kennicutt-Schmidt relation. This work uses dimensionality reduction techniques to characterize the Galaxy Manifold within an 11-dimensional space of luminosities from far ultraviolet to infrared. This manifold can describe over 95% of the variance with just two parameters. These two parameters represent the many observed galaxy properties well, suggesting a scenario where galaxies move on the manifold with time. To demonstrate the potential of this technique, we present model-independent star formation histories derived by simply modeling the galaxies as a random walk process on the manifold. The found galaxy manifold will also be a convenient interface between the galaxy properties and the observed luminosities, facilitating galaxy evolution studies across cosmic time.
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