Abstract

Contributed Talk - Splinter StellarEndpoints

Friday, 11 September 2026, 14:20   (MW-2235)

ridging Supernova Shock Breakout in Confined-Shell CSM with Multiwavelength Early Light Curves via MGFLD Rad-Hydro

Wun-Yi Chen, Ke-Jung Chen, Keiichi Maeda, Friedrich K. Roepke, Po-Sheng Ou, Sung-Han Tsai
ASIAA, HITS, NTU

We present new multi-dimensional radiation hydrodynamic simulations of supernova shock breakout interacting with a confined-shell circumstellar medium (CS-CSM) using the code CASTRO. Utilizing a high-resolution multi-group flux-limited diffusion (MGFLD) scheme across 16 frequency groups, we establish 4 observational inspired 2D models to capture the detailed energy-dependent radiation-hydrodynamic coupling between the forward shock, its radiation precursor, and dense CSM profiles from first principles. Our models reveal that intense radiation precursors drive strong fluid instabilities and shift the effective photosphere outward prior to the shock's arrival at the nominal stellar surface. This geometric restructuring extends the shock breakout rise time non-uniformly across different wavelengths, a spectral distortion missed by standard grey approximations. To verify the validity of our 2D synthesis against three-dimensional symmetry-breaking effects, we complement this with a targeted 3D MGFLD simulation using a multi-level adaptive mesh refinement (AMR) grid. We confirm that while unrestricted 3D turbulent breaking produces rich filamentary and clumping structures that fracture the shell, the global energy distribution and multi-group radiative transport remain well-aligned. Through our MGFLD spectral bins, we integrate the emission to reconstruct full bolometric and band-by-band early light curves, revealing a distinctive, gradual color evolution from blue to red post-peak. By bridging numerical multi-group theory with observational reality, these high-fidelity synthetic templates provide critical multi-wavelength diagnostics for upcoming wide-field transient missions to effectively constrain pre-core-collapse mass-loss histories at stellar endpoints.