Evidence for the rapid formation of low mass early-type galaxies in dense environments

Understand

We explore the environmental dependence of star formation timescales in low mass galaxies using the [$\alpha$/Fe] abundance ratio as an evolutionary clock.

• We present integrated [$\alpha$/Fe] measurements for 11 low mass ($M_\star \sim 10^9~M_\odot$) early-type galaxies (ETGs) with a large range of cluster-centric distance in the Virgo Cluster.
• We find a gradient in [$\alpha$/Fe], where the galaxies closest to the cluster center (the cD galaxy, M87) have the highest values.
• This trend is driven by galaxies within a projected radius of 0.4~Mpc (0.26 times the virial radius of Virgo~A), all of which have super-solar [$\alpha$/Fe].