19 febbraio, 13:30 – 14:30

Speaker (AstroCoffee): Philippa Cole, (Chair: Gabriele Coppi)  Speaker (Short Seminar): Kazuki Tomaru (Osaka University)

Title: Evolution and Dynamics of Simulated Low-mass Dwarf Galaxies

Abstract: The dynamics of galaxies are directly affected by the physical processes of galaxy formation, such as feedback, gas accretion, and galaxy mergers. Therefore, the dynamical properties of galaxies provide much information for understanding galaxy evolution. In particular, that of low-mass galaxies, such as the first galaxies, will be important for revealing the early stages of galaxy evolution. Recently, gas dynamics of nearby star-forming dwarf galaxies have been observed by the EMPRESS project (e.g. Isobe+’23), and low-mass galaxies at high redshift (z>4) are also being observed by ALMA, JWST, and Subaru. Therefore, we performed cosmological zoom-in simulations of field dwarf galaxies in the low-density environments evolving to Mstar ~ 10^7-8 Msun at z=0 using the cosmological SPH code GADGET4-Osaka. At z = 0, the gas in the simulated galaxies is dispersion-dominated, in good agreement with observations and previous simulations. We also find that galaxy mergers play an important role in creating observed relationships between the ratio Vrot/sigma, the ratio between the rotational motion and dispersion of gas, and the gas-phase metallicity and specific star formation rate. Our results suggest that at least some dwarf irregulars could be the result of galaxy mergers, consistently with some observations.