Chemical signature of gas-rich disc-disc mergers at high redshift
  We performed numerical simulations of mergers between gas-rich disc galaxies, which result in the formation of late-type galaxies. Stars formed during the merger end up in a thick disc that is partially supported by velocity dispersion and has high [alpha/Fe] ratios at all metallicities. Stars formed later end up in a thin, rotationally supported disc which has lower [alpha/Fe] ratios. While the structural and kinematical properties of the merger remnants depend strongly upon the orbital parameters of the mergers, we find a clear chemical signature of gas-rich mergers. 
Hugo Martel, Simon Richard, Chris B. brook, Daisuke Kawata, Brad K.   Gibson, Patricia S\'anchez-Bl\'azquez
astro-ph.CO