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A Lensed Arc in the Low Redshift Cluster Abell 2124

John P. Blakeslee·Mark R. Metzger
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Abstract

We report the discovery of an arc-like object 27" from the center of the cD galaxy in the redshift $z=0.066$ cluster A2124. Observations with the Keck II telescope reveal that the object is a background galaxy at $z=0.573$, apparently lensed into an arc of length \sim 8 \farcs5 and total R magnitude $m_R = 20.86\pm0.07$. The width of the arc is resolved; we estimate it to be $\sim$0\farcs6 after correcting for seeing. A lens model of the A2124 core mass distribution consistent with the cluster galaxy velocity dispersion reproduces the observed arc geometry and indicates a magnification factor $\gta $9. With this magnification, the strength of the [OII] λ3727 line implies a star-formation rate of SFR \sim 0.4 h^{-2}\msun yr^{-1}$. A2124 thus appears to be the lowest redshift cluster known to exhibit strong lensing of a distant background galaxy.

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John P. Blakeslee, Mark R. Metzger. 1998-10-09. A Lensed Arc in the Low Redshift Cluster Abell 2124. https://doi.org/10.1086/306906

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