H I Detection of Two Dwarf S0 Galaxies in Nearby Groups: ESO 384-016 and NGC 59

Abstract

A H I survey of 10 dE/dS0 galaxies in the nearby Sculptor and Centaurus A groups was made using the Australia Telescope Compact Array. The observed galaxies have accurate distances derived by Jerjen et al. using the surface brightness fluctuation technique. Their absolute magnitudes are in the range -9.5 > MB > -15.3. Only two of the 10 galaxies were detected at our detection limit (∼1.0 × 106 M⊙ for the Centaurus group and ∼5.3 × 105 M⊙ for the Sculptor group): The two dS0 galaxies ESO 384-016 in the Centaurus A group and NGC 59 in the Sculptor group, with H I masses of (6.0 ± 0.5) × 106 and (1.4 ± 0.1) × 107 M⊙, respectively. Those two detections were confirmed using the Green Bank Telescope. These small H I reservoirs could fuel future generations of low-level star formation and could explain the bluer colors seen at the center of the detected galaxies. Similar to what is seen with the Virgo dwarf ellipticalss, the two objects with H I appear to be on the outskirts of the groups.