10:30–11:00 am
ERC 401 Modeling Stochastic Star Formation History of Dwarf Galaxies in GRUMPY We investigate the impact of bursty star formation on several galaxy scaling relations in dwarf galaxies using the GRUMPY model. While this simple regulator-type model reproduces the average trend of the SFR-mass, stellar mass-gas mass, stellar mass-metallicity relation, and CMD, the scatter of these relations in the original model is smaller than observed. To address this, we use a formula for the power spectral density (PSD) to generate a series of random numbers with a log-normal distribution that perturbs the original SFR. We adjust the parameters in the PSD formalism to control the amplitude and variability of burstiness in the model, and experiment with the effects of long-term and short-term SFR variations in the model, comparing the results to observations. We select PSD parameters that produce a stochastic SFR exhibiting both short-term and long-term variations, with a burstiness amplitude comparable to simulations. We find that bursty star formation slightly increases the scatter in the SFR-mass relation compared to the non-bursty case, but does not fully explain the high SFR of starburst galaxies. We discuss potential biases associated with different SFR indicators, suggesting that extreme SFR values in starburst galaxies could be due to their use of H-alpha as an indicator, which tends to produce higher SFR estimates. Furthermore, we find that bursty star formation increases the scatter in the CMD, particularly for brighter dwarf galaxies (Mv < −12). However, the scatter for fainter dwarf galaxies (Mv > −12) is comparable to the non-bursty model. This could be due to low-mass dwarf galaxies being quenched long ago by reionization, so any perturbation to their SFR would not have a significant effect. Finally, we demonstrate that introducing a bursty SFR does not disrupt the chemical relation of dwarf galaxies and generate a population of extremely metal-poor dwarf galaxies reported in observations.
Advisor: Andrey Kravtsov
May
24