We report optical and near-infrared broad band observations of the short-duration GRB 050724 host galaxy , used to construct its spectral energy distribution ( SED ) .
Unlike the hosts of long-duration gamma-ray bursts ( GRBs ) , which show younger stellar populations , the SED of the GRB 050724 host galaxy is optimally fitted with a synthetic elliptical galaxy template based on an evolved stellar population ( age \sim 2.6 Gyr ) .
The SED of the host is difficult to reproduce with non-evolving metallicity templates .
In contrast , if the short GRB host galaxy metallicity enrichment is considered , the synthetic templates fit the observed SED satisfactorily .
The internal host extinction is low ( A _ { v } \lesssim 0.4 mag ) so it can not explain the faintness of the afterglow .
This short GRB host galaxy is more massive ( \sim 5 \times 10 ^ { 10 } M _ { \odot } ) and luminous ( \sim 1.1 L ^ { \star } ) than most of the long-duration GRB hosts .
A statistical comparison based on the ages of short- and long-duration GRB host galaxies strongly suggests that short-duration GRB hosts contain , on average , older progenitors .
These findings support a different origin for short- and long-duration GRBs .