We report Keck LRIS observations of an arc-like background galaxy near the center of Abell 2152 ( z = 0.043 ) , one of the three clusters comprising the Hercules supercluster .
The background object has a redshift z = 0.1423 and is situated 25″ north of the primary component of the A2152 brightest cluster galaxy ( BCG ) .
The object is about 15″ in total length and has a reddening-corrected R -band magnitude of m _ { R } = 18.55 \pm 0.03 .
Its spectrum shows numerous strong emission lines , as well as absorption features .
The strength of the H \alpha emission would imply a star formation rate \hbox { SFR } \approx 3 h ^ { -2 } { \hbox { M$ { } _ { \odot } $ } } yr ^ { -1 } in the absence of any lensing .
However , the curved shaped of this object and its tangential orientation along the major axis of the BCG suggest lensing .
We model the A2152 core mass distribution including the two BCG components and the cluster potential .
We present velocity and velocity dispersion profile measurements for the two BCG components and use these to help constrain the potential .
The lens modeling indicates a likely magnification factor of \sim 1.9 for the lensed galaxy , making A2152 the nearest cluster in which such significant lensing of a background source has been observed .
Finally , we see evidence for a concentration of early-type galaxies at z = 0.13 near the centroid of the X-ray emission previously attributed to A2152 .
We suggest that emission from this background concentration is the cause of the offset of the X-ray center from the A2152 BCG .
The background concentration and the dispersed mass of the Hercules supercluster could add further to the lensing strength of the A2152 cluster .