Collisionless simulations of structure formation with significant local
primordial non-Gaussianities at Mpc scales have shown that a non-Gaussian tail
favouring underdensities, with a negative fNL parameter, can
significantly change the merging history of galaxy-sized dark matter halos,
which then typically assemble later than in vanilla ΛCDM. Moreover,
such a small-scale negative fNL could have interesting consequences
for the cosmological S8 tension. Here, we complement our previous work on
collisionless simulations with new hydrodynamical simulations of galaxy
formation in boxes of 30 Mpc/h, using the {\sc RAMSES} code. In particular,
we show that all feedback prescriptions being otherwise identical, simulations
with a negative fNL∼−1000 on small scales, hence forming galaxies
a bit later than in vanilla ΛCDM, allow to form simulated galaxies with
more disky kinematics than in the vanilla case. Therefore, such small-scale
primordial non-Gaussianities could potentially help alleviate, simultaneously,
tensions in cosmology and galaxy formation. These hydrodynamical simulations on
small scales will need to be complemented with larger box simulations with
scale-dependent non-Gaussianities, to statistically confirm these trends and
explore their observational consequences in further detail.Comment: 14 pages, 8 figures, comments welcome :