We use ACS data from the HST Treasury survey of the Coma cluster ( z \sim 0.02 ) to study the properties of barred galaxies in the Coma core , the densest environment in the nearby Universe .
This study provides a complementary data point for studies of barred galaxies as a function of redshift and environment .
From \sim 470 cluster members brighter than M _ { I } = -11 mag , we select a sample of 46 disk galaxies ( S0–Im ) based on visual classification .
The sample is dominated by S0s for which we find an optical bar fraction of 47 \pm 11 % through ellipse fitting and visual inspection .
Among the bars in the core of the Coma cluster , we do not find any very large ( a _ { bar } > 2 kpc ) bars .
Comparison to other studies reveals that while the optical bar fraction for S0s shows only a modest variation across low-to-intermediate density environments ( field to intermediate-density clusters ) , it can be higher by up to a factor of \sim 2 in the very high-density environment of the rich Coma cluster core .