We identify and study the properties of nucleated dwarf galaxies in the MATLAS Survey. Using a 2D model-fitting procedure, we derive their morphological parameters. We investigate the nature of the central compact nucleus and identify those with an AGN. These measurements are used to gain a better understanding of the nature of nucleated dwarfs and constrain their formation scenario. From our sample of 364 nucleated dwarf galaxies, 255 were fitted successfully with Sérsic profiles and central Point Spread Function (PSF) or King profile using Galfit software package.
The median Sérsic index of the diffuse component of nucleated dwarf is 1.03 which is a bit higher than the usual value for non-nucleated dwarfs ( 0.7), but within the range of nucleated dwarf studies from cluster environments. The median value of the axis ratio is 0.77 which is in agreement with the existing observations that, the nucleated dwarfs are more spherical than elliptical in shape. The magnitudes of the nuclei are positively correlated with the magnitudes of the host galaxies. The linear relationship is steeper for those fitted with a central King profile. For the subsample with matched spectral redshift from the Sloan Digital Sky Survey, the range of distances to the dwarf galaxies is 8Mpc < D < 50Mpc, the range of diffuse component magnitudes is -13 < Mg < -17, and the range of nuclei magnitudes is -7 < M g < -12. The median offset between nucleus and photocenter is 0.4 arcseconds which differs from the limited existing works about this property. While most of the nuclei in the sample have signatures of star forming activity as seen from the diagnostic diagrams, a few strong and weak AGN candidates are also identified.
This work, along with the study of the non-nucleated dwarf galaxies from the MATLAS survey will provide invaluable insight and information about the shapes, distribution, and characteristics of dwarf galaxies from field environment. This significantly larger volume limited sample of dwarf galaxies compared to the currently existing sample of local dwarfs in literature will allow a statistical comparison between dwarf galaxies in different environments for the first time.