Redshift evolution of Tully-Fisher relation in the EAGLE simulation

FERRERO ISMAEL; ABADI MARIO GABRIEL

Workshop; Workshop on Large Scale Structure: from Galaxies to the Cosmic Web; 2016

The Tully-Fisher (TF) relation links the stellar content of disk galaxies with their rotation velocity, being one of the most fundamental scaling relation for disk galaxies. We use the EAGLE cosmological simulation to study the stellar-mass TF relation and its redshift evolution for the population of rotationally-supported galaxies with stellar mass Mstr > 109 M⊙. We find a good agreement with available observations up to z = 1, which indicate no evolution in the slope and a weak decrease in the TF zeropoint with redshift. Simulated galaxies have flat rotation curves but the relevance of the baryons depend on their mass. For Mstr < 2 × 1010 M⊙ galaxies are dark-matter dominated at all redshifts and consistent with sub-maximal disks where baryons account for only 28% of the mass within the half-mass radius of the stars rhalf. For more massive objects, stars can have equal or larger contributions than the dark matter, specially at high redshifts, and we see a correlation between the deviations in the TF and the disks surface brightness. The slope of the TF is quite steep, Mstr ∝ Vhalf3.3, where Vhalf is the circular velocity measured at rhalf. This steep slope can be explained by a simple model based on the scaling of virial quantities modulated by the varying efficiency of halos to collect baryons at their centers. The same model can also explain the weak evolution of the zero-point, mainly as a result of a weakly-evolving relation between stellar mass and halo mass, which is consistent with arguments from abundance matching. We report predictions for the stellar-mass TF relation up to z ∼ 2.2 that can be tested once unbiased observational data becomes available.