We report the discovery of 158 previously undetected dwarf galaxies in the Fornax cluster central regions using a deep coadded u, g and i-band image obtained with the DECam wide-field camera mounted on the 4meter Blanco telescope at the Cerro Tololo Interamerican Observatory as part of the Next Generation Fornax Survey (NGFS). The new dwarf galaxies have quasi-exponential light profiles, effective radii 0.1 < r e < 2.8 kpc and average effective surface brightness values 22.0 < µ i < 28.0 mag arcsec −2 . We confirm the existence of ultra-diffuse galaxies (UDGs) in the Fornax core regions that resemble counterparts recently discovered in the Virgo and Coma galaxy clusters. We also find extremely low surface brightness NGFS dwarfs, which are several magnitudes fainter than the classical UDGs. The faintest dwarf candidate in our NGFS sample has an absolute magnitude of M i = −8.0 mag. The nucleation fraction of the NGFS dwarf galaxy sample appears to decrease as a function of their total luminosity, reaching from a nucleation fraction of > 75% at luminosities brighter than M i ≃ −15.0 mag to 0% at luminosities fainter than M i ≃ −10.0 mag. The two-point correlation function analysis of the NGFS dwarf sample shows an excess on length scales below ∼100 kpc, pointing to the clustering of dwarf galaxies in the Fornax cluster core.

We present a photometric study of the dwarf galaxy population in the core region (≲ r vir 4) of the Fornax galaxy cluster based on deep u ′ g ′ i ′ photometry from the Next Generation Fornax Cluster Survey. All imaging data were obtained with the Dark Energy Camera mounted on the 4-meter Blanco telescope at the Cerro-Tololo Interamerican Observatory. We identify 258 dwarf galaxy candidates with luminosities −17 ≲ M g ′ ≲ −8 mag, corresponding to typical stellar masses of 9.5 ≳ log M ⋆ M ⊙ ≳ 5.5, reaching ∼ 3 mag deeper in point-source luminosity and ∼4 mag deeper in surface-brightness sensitivity compared to the classic Fornax Cluster Catalog. Morphological analysis shows that the dwarf galaxy surface-brightness profiles are well represented by singlecomponent Sérsic models with average Sérsic indices of ⟨n⟩ u ′ ,g ′ ,i ′ = (0.78 − 0.83) ± 0.02, and average effective radii of ⟨r e ⟩ u ′ ,g ′ ,i ′ = (0.67 − 0.70) ± 0.02 kpc. Color-magnitude relations indicate a flattening of the galaxy red sequence at faint galaxy luminosities, similar to the one recently discovered in the Virgo cluster. A comparison with population synthesis models and the galaxy mass-metallicity relation reveals that the average faint dwarf galaxy is likely older than ∼5 Gyr. We study galaxy scaling relations between stellar mass, effective radius, and stellar mass surface density over a stellar mass range covering six orders of magnitude. We find that over the sampled stellar mass range several distinct mechanisms of galaxy mass assembly can be identified: i) dwarf galaxies assemble mass inside the half-mass radius up to log M ⋆ ≈ 8.0, ii) isometric mass assembly in the range 8.0 ≲ log M ⋆ M ⊙ ≲ 10.5, and iii) massive galaxies assemble stellar mass predominantly in their halos at log M ⋆ ≈10.5 and above.

We present the results of a wide spectroscopic survey aimed at detecting extragalactic globular clusters (GCs) in the core of the Fornax cluster. About 4500 low resolution spectra (from 4800 to 10000Å) were observed in 25 VLT/VIMOS masks covering the central 1 deg 2 around the dominant galaxy NGC 1399 corresponding to ∼175 kpc galactocentric radius. We describe the methodology used for data reduction and data analysis. We found a total of 387 unique physical objects (372 GCs and 15 ultra compact dwarfs) in the field covered by our observations. Most of these objects are associated with NGC 1399, with only 10% likely belonging to other giant galaxies. The new VIMOS dataset is complementary to the many GC catalogues already present in the literature and it brings the total number of tracer particles around NGC 1399 to more than 1130 objects. With this comprehensive radial velocity sample we have found that the velocity dispersion of the GC population (equally for red and blue GC populations) shows a relatively sharp increase from low velocity dispersion (∼ 250 − 350 km s −1 ) to high velocity dispersion (∼ 300 − 400 km s −1 ) at projected radius of ≈ 10 arcmin (∼ 60 kpc) from the galaxy centre. This suggests that at a projected radius of ≈ 60 kpc both blue and red GC populations begin to be governed by the dominating Fornax cluster potential, rather than by the central NGC 1399 galaxy potential. This kinematic evidence corroborates similar results found using surface brightness analysis and planetary nebulae kinematics.