Studies of nucleated dwarf galaxies can constrain the scenarios for the formation and evolution of nuclear star clusters ( NSC ) in low-mass galaxies and give us insights on the origin of ultra compact dwarf galaxies ( UCDs ) .
We report the discovery of a NSC in the dwarf galaxy KKs58 and investigate its properties together with those of another NSC in KK197 .
Both NSCs are hosted by dwarf elliptical galaxies of the Centaurus group .
Combining ESO VLT MUSE data with photometry from VLT FORS2 , CTIO Blanco DECam , and HST ACS , as well as high-resolution spectroscopy from VLT UVES , we analyse the photometric , kinematic and stellar population properties of the NSCs and their host galaxies .
We confirm membership of the NSCs based on their radial velocities and location close to the galaxy centres .
We also confirm the membership of two globular clusters ( GCs ) and detect oblate rotation in the main body of KK197 .
Based on high signal-to-noise spectra taken with MUSE of the NSCs of both KKs58 and KK197 we measure low metallicities , [ Fe/H ] = -1.75 \pm 0.06 dex and [ Fe/H ] = -1.84 \pm 0.05 dex , and stellar masses of 7.3 \times 10 ^ { 5 } M _ { \sun } and 1.0 \times 10 ^ { 6 } M _ { \sun } , respectively .
Both NSCs are more metal-poor than their hosts that have metallicities of -1.35 \pm 0.23 dex ( KKs58 ) and -0.84 \pm 0.12 dex ( KK197 ) .
This can be interpreted as NSC formation via the in-spiral of GCs .
The masses , sizes and metallicities of the two NSCs place them among other NSCs , but also among the known UCDs of the Centaurus group .
This indicates that NSCs might constitute the progenitors of a part of the low-mass UCDs , although their properties are almost indistinguishable from typical GCs .