Substructures within Substructures in the Complex Post-Merging System A514 Unveiled by High-Resolution Magellan/Megacam Weak Lensing

Abell 514 (A514) at $z=0.071$ is an intriguing merging system exhibiting highly elongated (~1 Mpc) X-ray features and three large-scale (300~500 kpc) bent radio jets. To dissect this system with its multi-wavelength data, it is critical to robustly identify and quantify its dark matter (DM) substructures. We present a weak-lensing analysis of A514 using deep Magellan/Megacam observations. Combining two optical band filter imaging data obtained under optimal seeing (~0.''6) and leveraging the proximity of A514, we achieve a high source density of ~46arcmin⁻² or ~6940Mpc⁻², which enables high-resolution mass reconstruction. We unveil the complex DM substructures of A514, which are characterized by the NW and SE subclusters separated by ~$0.7$Mpc, each exhibiting a bimodal mass distribution. The total mass of the NW subcluster is estimated to be MNW200c = 1.08-0.22+0.24 × 10¹⁴ M_ and is further resolved into the eastern (MNWE200c = 2.6-1.1+1.4 × 10¹³ M_) and western (MNWW200c = 7.1-2.0+2.3 × 10¹³ M_) components. The mass of the SE subcluster is MSE200c = 1.55-0.26+0.28 × 10¹⁴ M_, which is also further resolved into the northern (MSEN200c = 2.9-1.3+1.8 × 10¹³ M_) and southern (MSES200c = 8.5-2.6+3.0 × 10¹³ M_) components. These four substructures coincide with the A514 brightest galaxies and are detected with significances ranging from 3.4σ to 4.8σ. Comparison of the dark matter substructures with the X-ray distribution suggests that A514 might have experienced an off-axis collision, and the NW and SE subclusters are currently near their apocenters.