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Galaxy mergers and interactions are expected to play a significant role leading to offsets between gas and stellar motions in galaxies. Herein we crossmatch galaxies in MaNGA MPL-8 with the Dark Energy Spectroscopic Instrument (DESI) Legacy Surveys and identify 311 merging galaxies that have reliable measurements of the $\Delta$PA, the difference between the stellar and gas kinematic position angles to investigate the impacts of merging on gas-stellar rotation misalignments. We find that the merging fractions of misaligned galaxies (30$^\circ$ $\leqslant$ $\Delta$PA $<$150$^\circ$) are higher than that of co-rotators ($\Delta$PA $<$ 30$^\circ$) in both quiescent and star-forming galaxies. This result suggests that merging is one process to produce kinematic misalignments. The merging fraction of counter-rotators ($\Delta$PA $\leqslant$ 150$^\circ$) is lower than that of misaligned galaxies in both quiescent and star-forming galaxies, while in the latter it is likely even lower than that of co-rotators. The orbital angular momentum transfer to the spins of stars and gas during merging and the tidal feature disappearance can lead to small merging fractions in counter-rotators. Numerous new stars that inherit angular momentum from gas after merging can further lower the merging fraction of star-forming counter-rotators., Comment: 11 pages, 6 figures, accepted by MNRAS

Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations and more intense, ongoing star formation than their outer parts, indicating ongoing growth of the central regions. The result offers observational evidence that the acquisition of external gas in blue galaxies is possible; the interaction with pre-existing gas funnels the gas into nuclear regions (< 1 kpc) to form new stars., Comment: 20 pages, 7 figures, 1 table