We present the first deep color-magnitude diagram of the Canes Venatici I ( CVnI ) dwarf galaxy from observations with the wide field Large Binocular Camera on the Large Binocular Telescope .
Reaching down to the main-sequence turnoff of the oldest stars , it reveals a dichotomy in the stellar populations of CVnI : it harbors an old ( \mathrel { \hbox to 0.0 pt { \lower 3.0 pt \hbox { $ \mathchar 536 $ } \hss } \raise 2.0 pt% \hbox { $ \mathchar 318 $ } } 10 Gyr ) , metal-poor ( { [ Fe / H ] } \sim - 2.0 ) and spatially extended population along with a much younger ( \sim 1.4 - 2.0 Gyr ) , 0.5 dex more metal-rich , and spatially more concentrated population .
These young stars are also offset by 64 _ { -20 } ^ { +40 } { pc } to the East of the galaxy center .
The data suggest that this young population , which represent \sim 3 - 5 \% of the stellar mass of the galaxy within its half-light radius , should be identified with the kinematically cold stellar component found by Ibata et al .
( 8 ) .
CVnI therefore follows the behavior of the other remote MW dwarf spheroidals which all contain intermediate age and/or young populations : a complex star formation history is possible in extremely low-mass galaxies .