The Galaxy Major Merger Fraction to z ~ 1
  Aims: We study the major merger fraction in a SPITZER/IRAC-selected catalogue
in the GOODS-S field up to z ~ 1 for luminosity- and mass-limited samples.
  Methods: We select disc-disc merger remnants on the basis of morphological
asymmetries, and address three main sources of systematic errors: (i) we
explicitly apply morphological K-corrections, (ii) we measure asymmetries in
galaxies artificially redshifted to z_d = 1.0 to deal with loss of
morphological information with redshift, and (iii) we take into account the
observational errors in z and A, which tend to overestimate the merger
fraction, though use of maximum likelihood techniques.
  Results: We obtain morphological merger fractions (f_m) below 0.06 up to z ~
1. Parameterizing the merger fraction evolution with redshift as f_m(z) =
f_m(0) (1+z)^m, we find that m = 1.8 +/- 0.5 for M_B <= -20 galaxies, while m =
5.4 +/- 0.4 for M_star >= 10^10 M_Sun galaxies. When we translate our merger
fractions to merger rates (R_m), their evolution, parameterized as R_m(z) =
R_m(0) (1+z)^n, is quite similar in both cases: n = 3.3 +/- 0.8 and n = 3.5 +/-
0.4, respectively.
  Conclusions: Our results imply that only ~8% of today's M_star >= 10^10 M_Sun
galaxies have undergone a disc-disc major merger since z ~ 1. In addition, ~21%
of this mass galaxies at z ~ 1 have undergone one of these mergers since z ~
1.5. This suggests that disc-disc major mergers are not the dominant process in
the evolution of M_star >= 10^10 M_Sun galaxies since z ~ 1, but may be an
important process at z > 1.
