Searching for star-forming dwarf galaxies in the Antlia cluster ^⋆

¹ Isaac Newton Group of Telescopes, Apto. 321, 38700 Santa Cruz de la Palma, Canary Islands, Spain
e-mail: ovidiuv@ing.iac.es
² Instituto de Astrofísica de Andalucía (CSIC), Apto. 3004, 18080 Granada, Spain
³ Grupo de Investigación CGGE, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque, B1900FWA La Plata, Argentina
⁴ Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033 AAJ Ciudad Autónoma de Buenos Aires, Argentina
⁵ Instituto de Astrofísica de La Plata (CCT-La Plata, CONICET-UNLP), Paseo del Bosque, B1900FWA La Plata, Argentina

Received: 5 September 2013
Accepted: 31 January 2014

Abstract

Context. The formation and evolution of dwarf galaxies in clusters need to be understood, and this requires large aperture telescopes.

Aims. In this sense, we selected the Antlia cluster to continue our previous work in the Virgo, Fornax, and Hydra clusters and in the Local Volume (LV). Because of the scarce available literature data, we selected a small sample of five blue compact dwarf (BCD) candidates in Antlia for observation.

Methods. Using the Gemini South and GMOS camera, we acquired the Hα imaging needed to detect star-forming regions in this sample. With the long-slit spectroscopic data of the brightest seven knots detected in three BCD candidates, we derived their basic chemical properties. Using archival VISTA VHS survey images, we derived K_S magnitudes and surface brightness profile fits for the whole sample to assess basic physical properties.

Results. FS90-98, FS90-106, and FS90-147 are confirmed as BCDs and cluster members, based on their morphology, K_S surface photometry, oxygen abundance, and velocity redshift. FS90-155 and FS90-319 did not show any Hα emission, and they could not be confirmed as dwarf cluster star-forming galaxies. Based on our data, we studied some fundamental relations to compare star forming dwarfs (BCDs and dIs) in the LV and in the Virgo, Fornax, Hydra, and Antlia clusters.

Conclusions. Star-forming dwarfs in nearby clusters appear to follow same fundamental relations in the near infrared with similar objects in the LV, specifically the size-luminosity and the metallicity-luminosity, while other more fundamental relations could not be checked in Antlia due to lack of data.