The Hamburg/ESO quasar HE 1113 - 0641 is found to be a quadruple gravitational lens , based on observations with the twin 6.5m Magellan telescopes at the Las Campanas Observatory , and subsequently with the Hubble Space Telescope .
The z _ { S } = 1.235 quasar appears in a cross configuration , with i ^ { \prime } band magnitudes ranging from 18.0 to 18.8 .
With a maximum image separation of 0 \farcs { } 67 , this is the smallest-separation quadruple ever identified using a ground-based optical telescope .
PSF subtraction reveals a faint lensing galaxy .
A simple lens model succeeds in predicting the observed positions of the components , but fails to match their observed flux ratios by up to a magnitude .
We estimate the redshift of the lensing galaxy to be z _ { L } \sim 0.7 .
Time delay estimates are on the order of a day , suggesting that the flux ratio anomalies are not due to variability of the quasar , but may result from substructure or microlensing in the lens galaxy .