Galaxy populations in the Hydra I cluster from the VEGAS survey: I. Optical properties of a large sample of dwarf galaxies

• Published in: Astronomy and astrophysics (Berlin) 2022-03, Vol.659, p.A92
• Main Authors: La Marca, Antonio, Peletier, Reynier, Iodice, Enrichetta, Paolillo, Maurizio, Choque Challapa, Nelvy, Venhola, Aku, Forbes, Duncan A., Cantiello, Michele, Hilker, Michael, Rejkuba, Marina, Arnaboldi, Magda, Spavone, Marilena, D’Ago, Giuseppe, Raj, Maria Angela, Ragusa, Rossella, Mirabile, Marco, Rampazzo, Roberto, Spiniello, Chiara, Mieske, Steffen, Schipani, Pietro
• Format: Article
• Language: English
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/202141901

Context. Due to their relatively low stellar mass content and diffuse nature, the evolution of dwarf galaxies can be strongly affected by their environment. Analyzing the properties of the dwarf galaxies over a wide range of luminosities, sizes, morphological types, and environments, we can obtain insights about their evolution. At ∼50 Mpc, the Hydra I cluster of galaxies is among the closest cluster in the z  ≃ 0 Universe, and an ideal environment to study dwarf galaxy properties in a cluster environment. Aims. We exploit deep imaging data of the Hydra I cluster to construct a new photometric catalog of dwarf galaxies in the cluster core, which is then used to derive properties of the Hydra I cluster dwarf galaxy population as well as to compare it with other clusters. Moreover, we investigate the dependency of dwarf galaxy properties on their surrounding environment. Methods. The new wide-field g - and r -band images of the Hydra I cluster obtained with the OmegaCAM camera on the VLT Survey Telescope (VST) in the context of the VST Early-type GAlaxy Survey (VEGAS) were used to study the dwarf galaxy population in the Hydra I cluster core down to r -band magnitude M r  = −11.5 mag. We used an automatic detection tool to identify dwarf galaxies from a ∼1 deg 2 field centered on the Hydra I core, covering almost half of the cluster virial radius. The photometric pipeline was used to estimate the principal photometric parameters for all targets. Scaling relations and visual inspection were used to assess the cluster membership and construct a new dwarf galaxy catalog. Finally, based on the new catalog, we studied the structural (Sérsic index n , effective radius R e , and axis ratio) and photometric (colors and surface brightness) properties of the dwarf galaxies, also investigating how they vary as a function of clustercentric distance. Results. The new Hydra I dwarf catalog contains 317 galaxies with a luminosity between −18.5