Cluster-Cluster Lensing and the Case of Abell 383

TL;DR

This paper evaluates the likelihood and characteristics of galaxy cluster-cluster lensing events, predicts their numbers under various models, and reports a potential detection in Abell 383, enhancing understanding of large-scale structure lensing.

Contribution

It provides the first detailed predictions of cluster-cluster lensing frequencies in different regimes and reports a possible observational case in Abell 383.

Findings

Predicted several to a few dozen strong-lensing CCLs depending on model assumptions.

Predicted a larger number of weak-lensing CCLs.

Reported a potential CCL detection in Abell 383 with background structures magnified.

Abstract

Extensive surveys of galaxy clusters motivate us to assess the likelihood of cluster-cluster lensing (CCL), namely, gravitational-lensing of a background cluster by a foreground cluster. We briefly describe the characteristics of CCLs in optical, X-ray and SZ measurements, and calculate their predicted numbers for $\Lambda$CDM parameters and a viable range of cluster mass functions and their uncertainties. The predicted number of CCLs in the strong-lensing regime varies from several ($<10$) to as high as a few dozen, depending mainly on whether lensing triaxiality bias is accounted for, through the c-M relation. A much larger number is predicted when taking into account also CCL in the weak-lensing regime. In addition to few previously suggested CCLs, we report a detection of a possible CCL in A383, where background candidate high-$z$ structures are magnified, as seen in deep Subaru observations.