  GRB 190114C is the first GRB for which the detection of very-high energy
emission up to the TeV range has been reported. It is still unclear whether
environmental properties might have contributed to the production of these very
high-energy photons, or if it is solely related to the released GRB emission.
The relatively low redshift of the GRB (z=0.425) allows us to study the host
galaxy of this event in detail, and to potentially identify idiosyncrasies that
could point to progenitor characteristics or environmental properties
responsible for such a unique event. We use ultraviolet, optical, infrared and
submillimetre imaging and spectroscopy obtained with HST, VLT and ALMA to
obtain an extensive dataset on which the analysis of the host galaxy is based.
The host system is composed of a close pair of interacting galaxies (Delta v =
50 km s^-1), both of which are well-detected by ALMA in CO(3-2). The GRB
occurred within the nuclear region (~170 pc from the centre) of the less
massive but more star-forming galaxy of the pair. The host is more massive
(log(M/M_odot)=9.3) than average GRB hosts at that redshift and the location of
the GRB is rather unique. The enhanced star-formation rate was probably
triggered by tidal interactions between the two galaxies. Our ALMA observations
indicate that both host galaxy and companion have a high molecular gas
fraction, as has been observed before in interacting galaxy pairs. The location
of the GRB within the core of an interacting galaxy with an extinguished
line-of-sight is indicative of a denser environment than typically observed for
GRBs and could have been crucial for the generation of the very-high-energy
photons that were observed.
