Discovery of Strong Lensing by an Elliptical Galaxy at Z=0.0345

We have discovered strong gravitational lensing by the galaxy ESO325–G004, in images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope. The lens galaxy is a boxy group-dominant elliptical at z = 0.0345, making this the closest known galaxy-scale lensing system. The lensed object is very blue (B− Ic ≈ 1.1), and forms two prominent arcs and a less extended third image. The Einstein radius is REin = 1.9 kpc (∼ 3 arcsec on the sky, cf. 12 arcsec effective radius of the lens galaxy). Assuming a high redshift for the source, the mass within REin is 1.4 × 10 M⊙, and the mass-to-light ratio is 1.8(M/L)⊙,I. The equivalent velocity dispersion is σlens = 310km s , in excellent agreement with the measured stellar dispersion σv = 320 km s . Modeling the lensing potential with a singular isothermal ellipse (SIE), we find close agreement with the light distribution. The best fit SIE model reproduces the ellipticity of the lens galaxy to ∼10%, and its position angle within 1. The model predicts the broad features of the arc geometry as observed; the unlensed magnitude of the source is estimated at Ic ∼ 23.75. We suggest that one in ∼200 similarly-massive galaxies within z < 0.1 will exhibit such a luminous multiply-imaged source. Subject headings: galaxies: elliptical and lenticular, cD — gravitational lensing