MARS: A New Maximum-entropy-regularized Strong Lensing Mass Reconstruction Method

Free-form strong-lensing (SL) mass reconstructions typically suffer from overfitting, which manifest itself as false-positive small-scale fluctuations. We present a new free-form MAximum-entropy ReconStruction (${\tt MARS}$) method without the assumption that light traces (LTM). The ${\tt MARS}$ algorithm enables us to achieve excellent convergence in source positions ~0.001$"$, minimize spurious fluctuations, and provide quasi-unique solution independently of initial conditions. Our is tested with publicly available synthetic SL data FF-SIMS}$ comparison truth shows reconstruction quality on par those best-performing LTM methods published literature, have been demonstrated outperform existing methods. In terms radial profile reconstruction, we $<1$% agreements for regions constrained by multiple images. Finally, apply A1689 find cluster regime dominated primary halo centered brightest galaxy weaker secondary also coincident bright member ~160 kpc northeast. Within field, well-described Navarro-Frenk-White (NFW) $c_{200}=5.53\pm0.77$ $r_s=538^{+90}_{-100}$ no evidence over-concentrated.