  We present observations of the type-2 Seyfert NGC7172 obtained with the
medium-resolution spectrometer (MRS) of the Mid-Infrared Instrument (MIRI) on
board of the JWST. This galaxy hosts one of the lowest ionised gas mass outflow
rates (Mout~0.005 M/yr) in a sample of six AGN with similar bolometric
luminosities (log Lbol~44erg/s) within the Galactic Activity, Torus and Outflow
Survey (GATOS). We aim to understand the properties of the ionised gas outflow,
mainly using the emission lines from the neon transitions, that cover a broad
range of ionisation potentials (IP) from ~20 eV to ~130 eV. We applied
parametric and non-parametric methods to characterise the line emission and
kinematics. The low excitation lines (IP<25eV, e.g.[NeII]) trace the rotating
disc emission. The high excitation lines (IP>90eV, e.g.[NeV]), which are likely
photoionised exclusively by the AGN, are expanding in the direction nearly
perpendicular to the disc of the galaxy, with maximum projected velocities of
~350-500 km/s. In particular, [NeV] and [NeVI] lines reveal a biconical ionised
gas outflow emerging N-S from the nuclear region, extending at least ~2.5"N and
3.8"S (projected distance of ~450 and 680 pc). Most of the emission arising in
the northern part of the cone was not previously detected due to obscuration.
Given the almost face-on orientation of the outflow and the almost edge-on
orientation of the galaxy, NGC7172 may be a case of weak coupling.
Nevertheless, we found evidence for positive feedback in two distinct
outflowing clumps at projected distances of 3.1" and 4.3" (i.e. ~560 and 780
pc) SW from the AGN. We estimated a star formation rate in these regions using
the [NeII] and [NeIII] luminosities of 0.08 M/yr, that is ~10% of that found in
the circumnuclear ring. The star formation activity might have been triggered
by the interaction between the ionised gas outflow and the ISM of the galaxy.
