We have imaged the recently discovered stellar overdensity located approximately one core radius from the center of the Fornax dwarf spheroidal galaxy using the Magellan Clay 6.5 m telescope with the Magellan Instant Camera. Superb seeing conditions allowed us to probe the stellar populations of this overdensity and of a control field within Fornax to a limiting magnitude of R = 26. The color-magnitude diagram of the overdensity field is virtually identical to that of the control field, with the exception of the presence of a population arising from a very short (less than 300 Myr in duration) burst of star formation 1.4 Gyr ago. Coleman et al. have argued that this overdensity might be related to a shell structure in Fornax that was created when Fornax captured a smaller galaxy. Our results are consistent with this model, but we argue that the metallicity of this young component favors a scenario in which the gas was part of Fornax itself.
- Galaxies: dwarf
- Galaxies: individual (Fornax dSph)
- Galaxies: stellar content - Local Group Online material: Machine-readable tables
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science