MrMARTIAN: A Multi-resolution Mass Reconstruction Algorithm Combining Free-form and Analytic Components

TL;DR

MrMARTIAN is a hybrid strong lensing modeling algorithm that combines free-form and analytic components, improving mass reconstruction stability and efficiency, especially with sparse multiple images, demonstrated on simulated and real galaxy cluster data.

Contribution

It introduces a multi-resolution hybrid algorithm that integrates analytic nodes into free-form modeling, enhancing stability and computational efficiency in strong lensing mass reconstructions.

Findings

Outperforms MARS in mass and magnification recovery

Provides more stable reconstructions with sparse multiple images

Achieves the smallest image-plane rms scatter for MACS J0416.1-2403

Abstract

We present ${\tt MrMARTIAN}$ (Multi-resolution MAximum-entropy Reconstruction Technique Integrating Analytic Node), a new hybrid strong lensing (SL) modeling algorithm. By incorporating physically motivated analytic nodes into the free-form method ${\tt MARS}$, ${\tt MrMARTIAN}$ enables stable and flexible mass reconstructions while mitigating oversmoothing in the inner mass profile. Its multi-resolution framework increases the degrees of freedom in regions with denser strong lensing constraints, thereby enhancing computational efficiency for a fixed number of free parameters. We evaluate the performance of ${\tt MrMARTIAN}$ using publicly available simulated SL data and find that it consistently outperforms ${\tt MARS}$ in recovering both mass and magnification. In particular, it delivers significantly more stable reconstructions when multiple images are sparsely distributed. Finally, we apply ${\tt MrMARTIAN}$ to the galaxy cluster MACS J0416.1-2403, incorporating two analytic nodes centered on the northeastern and southwestern BCGs. Our mass model, constrained by 412 multiple images, achieves an image-plane rms scatter of ~0".11, the smallest to date for this dataset.