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We use EAGLE to quantify the effect galaxy mergers have on the stellarspecific angular momentum of galaxies, $j_{\rm stars}$. We split mergers into:dry (gas-poor)/wet (gas-rich), major/minor, and different spin alignments andorbital parameters. Wet (dry) mergers have an average neutral gas-to-stellarmass ratio of $1.1$ ($0.02$), while major (minor) mergers are those withstellar mass ratios $\ge 0.3$ ($0.1-0.3$). We correlate the positions ofgalaxies in the $j_{\rm stars}$-stellar mass plane at $z=0$ with their mergerhistory, and find that galaxies of low spins suffered dry mergers, whilegalaxies of normal/high spins suffered predominantly wet mergers, if any. Theradial $j_{\rm stars}$ profiles of galaxies that went through dry mergers aredeficient by $\approx 0.3$~dex at $r\lesssim 10\,r_{50}$ (with $r_{50}$ beingthe half-stellar mass radius), compared to galaxies that went through wetmergers. Studying the merger remnants reveals that dry mergers reduce $j_{\rmstars}$ by $\approx 30$\%, while wet mergers increase it by $\approx 10$\%, onaverage. The latter is connected to the build-up of the bulge by newly formedstars of high rotational speed. Moving from minor to major mergers accentuatesthese effects. When the spin vectors of the galaxies prior to the dry mergerare misaligned, $j_{\rm stars}$ decreases to a greater magnitude, while in wetmergers co-rotation and high orbital angular momentum efficiently spun-upgalaxies. We predict what would be the observational signatures in the $j_{\rmstars}$ profiles driven by dry mergers: (i) shallow radial profiles and (ii)profiles that rise beyond $\approx 10\,r_{50}$, both of which are significantlydifferent from spiral galaxies.

Quantifying the impact of mergers on the angular momentum of simulated galaxies