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Recent long-term radio monitoring of tidal disruption events (TDEs) suggests that radio afterglows are common. Most studies argue that these afterglows may arise from forward shocks (FS) produced by the interaction between the TDE outflow and the hot, diffuse circumnuclear medium (CNM). Current theoretical models do not model the evolution of relativistic electrons in space, which introduces uncertainties. Here, we conducted hydrodynamic simulations to study the spatial evolution of relativistic electrons, and calculated the synchrotron spectra via radiative transfer. We focus on the FS scenario with non-relativistic outflows, and various parameters of the outflow and CNM are explored. A moderate outflow with kinetic energy of several 10<SUP>50</SUP> erg in a Galactic center─like CNM can produce mJy-level radio afterglows at a distance of 100 Mpc. The self-absorption frequency exhibits a slow decline at early times and a rapid decrease at late times. We derived the temporal evolution of the high-frequency radio flux, revealing its characteristic rise and decline pattern. We also find that (1) the radio spectra for narrow outflows are clearly anisotropic along different sight lines; (2) the FS parameters inferred from radio spectra using conventional analytical formulas deviate significantly from those in simulations, in which the inferred shock radii are half of those from simulations, and the inferred energies are an order of magnitude lower.

GRB 230307A is one of the brightest long-duration gamma-ray bursts (GRBs) ever detected, yet its progenitor remains uncertain due to the variety of plausible astrophysical scenarios. In this work, we investigate four possible progenitors for GRB 230307A: a binary neutron star (BNS), a neutron-star/white-dwarf (NS-WD) system, a neutron-star/black-hole merger, and a tidal disruption event involving a white dwarf and a supermassive black hole. Additionally, we explore three distinct central engine models powering the kilonova associated with the BNS: radioactive decay of <inline-formula><mml:math><mml:mi>r</mml:mi></mml:math></inline-formula>-process nuclei in a two-component ejecta model, a magnetar-driven model including magnetic dipole spin down, and a combined model of magnetar spin down with <inline-formula><mml:math><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>56</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math></inline-formula> radioactive decay. We perform Bayesian multiwavelength light curve analyses using physically motivated models and priors and evaluate model performance through Bayes factors and leave-one-out cross-validation scores. Our results show a statistical preference for a BNS or NS-WD progenitor producing a kilonova powered by a magnetar and <inline-formula><mml:math><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>56</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math></inline-formula> decay, characterized by a <inline-formula><mml:math><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>56</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math></inline-formula> mass of <inline-formula><mml:math><mml:mo>∼</mml:mo><mml:mn>4</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>4</mml:mn></mml:mrow></mml:msup><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula> and an ejecta mass of <inline-formula><mml:math><mml:mn>0.06</mml:mn><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula>. Furthermore, under the assumption of a BNS origin within this model, we infer binary component masses of <inline-formula><mml:math><mml:msub><mml:mi>m</mml:mi><mml:mn>1</mml:mn></mml:msub><mml:mo>=</mml:mo><mml:mn>1.3</mml:mn><mml:msubsup><mml:mn>2</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.06</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.05</mml:mn></mml:mrow></mml:msubsup><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula> and <inline-formula><mml:math><mml:msub><mml:mi>m</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mo>=</mml:mo><mml:mn>1.2</mml:mn><mml:msubsup><mml:mn>4</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.04</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.02</mml:mn></mml:mrow></mml:msubsup><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula>, with a dimensionless tidal deformability of <inline-formula><mml:math><mml:mover><mml:mi>Λ</mml:mi><mml:mo>∼</mml:mo></mml:mover><mml:mo>=</mml:mo><mml:mn>43</mml:mn><mml:msubsup><mml:mn>7</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>265</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>251</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>. From the component mass posteriors, we infer that the observed offset can be explained by a natal kick as long as the systemic velocity is nearly aligned with the prekick orbital motion. In this case, the required kick velocity (comoving frame) and binary separation range within <inline-formula><mml:math><mml:msubsup><mml:mi>v</mml:mi><mml:mi>k</mml:mi><mml:mo>'</mml:mo></mml:msubsup><mml:mo>∼</mml:mo><mml:mn>100</mml:mn><mml:mi>─</mml:mi><mml:mrow><mml:mn>150</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>km</mml:mi><mml:mo>/</mml:mo><mml:mi>s</mml:mi></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math><mml:msub><mml:mi>a</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:mo>∼</mml:mo><mml:mn>2</mml:mn><mml:mi>─</mml:mi><mml:mn>2.5</mml:mn><mml:msub><mml:mi>R</mml:mi><mml:mo>⊙</mml:mo></mml:msub></mml:math></inline-formula>, respectively.