Evolution of the mass, size, and star formation rate in high-redshift
  merging galaxies MIRAGE - A new sample of simulations with detailed stellar
  feedback
  We aim at addressing the questions related to galaxy mass assembly through
major and minor wet merging processes in the redshift range 1<z<2. A consequent
fraction of Milky Way like galaxies are thought to have undergone an unstable
clumpy phase at this early stage. Using the adaptive mesh refinement code
RAMSES, with a recent physically-motivated implementation of stellar feedback,
we build the Merging and Isolated high-Redshift Adaptive mesh refinement
Galaxies (MIRAGE) sample. It is composed of 20 mergers and 3 isolated idealized
disks simulations with global physical properties in accordance with the 1<z<2
mass complete sample MASSIV. The numerical hydrodynamical resolution reaches 7
parsecs in the smallest Eulerian cells. Our simulations include: star
formation, metal line cooling, metallicity advection, and a recent
implementation of stellar feedback which encompasses OB-type stars radiative
pressure, photo-ionization heating, and supernovae. The initial conditions are
set to match the z~2 observations, thanks to a new public code DICE. The
numerical resolution allows us to follow the formation and evolution of giant
clumps formed in-situ from Jeans instabilities triggered by high initial gas
fraction. The star formation history of isolated disks shows stochastic star
formation rate, which proceeds from the complex behavior of the giant clumps.
Our minor and major gas-rich merger simulations do not trigger starbursts,
suggesting a saturation of the star formation in a turbulent and clumpy
interstellar medium fed by substantial accretion from the circum-galactic
medium. Our simulations are close to the normal regime of the disk-like star
formation on a Schmidt-Kennicutt diagram. The mass-size relation and its rate
of evolution matches observations, suggesting that the inside-out growth
mechanisms of the stellar disk do not necessarily require to be achieved
through a cold accretion.
