The Extended Star Formation History of the Andromeda Spheroid at 21 kpc on the Minor Axis
The Extended Star Formation History of the Andromeda Spheroid at 21 kpc on the Minor Axis
Using the Hubble Space Telescope Advanced Camera for Surveys, we have obtained deep optical images of a southeast minor-axis field in the Andromeda galaxy, 21 kpc from the nucleus. In both star counts and metallicity, this field represents a transition zone between the metal-rich, highly disturbed inner spheroid that dominates …