Speaker
Description
Detecting and characterizing the low-mass galaxy population is one of the frontiers of astrophysics research. Observational measurements of such small ('dwarf') galaxies are particularly challenging due to their low surface-brightness. Therefore, the galaxy stellar mass function (GSMF), which helps us probe the halo mass function (HMF) and the underlying cosmology, suffers from uncertainties in low-mass regime. As low-mass star-forming galaxies are more likely to be centrals, these systems are key for measuring the GSMF and HMF in this mass regime. Moreover, for this type of galaxies, the star-formation rate density (SFRD) as a function of stellar mass provides a straightforward relation to the GSMF and allows us to characterize this population more thoroughly in a cosmological volume as galaxies with higher star-formation rates are easier to detect. In this work, we use two suites of high resolution cosmological simulations, EAGLE and TNG50, to perform a detailed study of their low-mass star-forming galaxy populations and of the relation of SFRD as a function of stellar mass, SFRD(M$_{*}$). We investigate this relation at different redshifts and use it as a new "metric" to make comparisons between the two sets of simulations, and with the observational measurements from the GAMA, MUSE and SDSS surveys. Our results indicate that the SFRD has a constant slope down to stellar masses of $10^{5.5} M_\odot\ $ and therefore there does not appear to be a turn-over in the GSMF at the low-mass end. The slope exhibits variations on different mass ranges and also with different physics prescriptions.
