Speaker: Constantina Fotopoulou

Date: Thursday 4 May 2023

Time: 14:00

Location: Online

The griffin project - Cold clouds in a very high resolution simulation of a dwarf starburst

We present the results of the analysis of the cold gas in a hydrodynamical simulation of a gas-rich dwarf galaxy merger resolved with individual massive stars at sub-parsec (0.1 pc) spatial and solar-mass (4M⊙) mass resolution. Our simulation supports a rapid disruption model for star-forming clouds by stellar radiation and supernova feedback. Our analysis reveals that the cold (Tgas < 300 K) star-forming gas is structured in compact clumps and filaments. We identify hundreds of cold clouds in each snapshot of the simulation with the typical irregular structure, masses and sizes of molecular clouds and we trace their lifecycle. The simulated cold clouds follow a power law mass function (CMF): dN/dM ∝ Mα with αmean = −1.78(±0.08), well in agreement with the observations. The slope α remains constant throughout the time of the simulation and is roughly the same for different gas particle density thresholds indicating self-similar structure. The simulated cold cloud properties follow the Larson relations and are well in agreement with observations. Tracing the lifecycle of the cold clouds we identify the growth phase, when the clouds gain enough mass for gravitational collapse and the beginning of star formation, and the destruction phase, when the energy and momentum input from newly formed stars lead to the dispersal of the clouds. We find a correlation between the peak mass and the size of the cold 1/2 clouds when they reach their peak mass: RMmax ∝ Mmax. High mass clouds live longer (up to 8 Myr) than lower mass clouds with peak mass Mmax < 104M⊙ which follow a power law lifetime distribution τlife ∝ M0.3 .