  Observations and simulations of interacting galaxies and mergers in the local
universe have shown that interactions can significantly enhance the star
formation rates (SFR) and fueling of Active Galactic Nuclei (AGN). However, at
higher redshift, some simulations suggest that the level of star formation
enhancement induced by interactions is lower due to the higher gas fractions
and already increased SFRs in these galaxies. To test this, we measure the SFR
enhancement in a total of 2351 (1327) massive ($M_*>10^{10}M_\odot$) major
($1<M_1/M_2<4$) spectroscopic galaxy pairs at 0.5<z<3.0 with $\Delta V <5000$
km s$^{-1}$ (1000 km s$^{-1}$) and projected separation <150 kpc selected from
the extensive spectroscopic coverage in the COSMOS and CANDELS fields. We find
that the highest level of SFR enhancement is a factor of 1.23$^{+0.08}_{-0.09}$
in the closest projected separation bin (<25 kpc) relative to a stellar mass-,
redshift-, and environment-matched control sample of isolated galaxies. We find
that the level of SFR enhancement is a factor of $\sim1.5$ higher at 0.5<z<1
than at 1<z<3 in the closest projected separation bin. Among a sample of
visually identified mergers, we find an enhancement of a factor of
1.86$^{+0.29}_{-0.18}$ for coalesced systems. For this visually identified
sample, we see a clear trend of increased SFR enhancement with decreasing
projected separation (2.40$^{+0.62}_{-0.37}$ vs.\ 1.58$^{+0.29}_{-0.20}$ for
0.5<z<1.6 and 1.6<z<3.0, respectively). The SFR enhancement seen in our
interactions and mergers are all lower than the level seen in local samples at
the same separation, suggesting that the level of interaction-induced star
formation evolves significantly over this time period.
