Circumstellar Medium of Supernovae as New Probes for Feebly-interacting Particles

Abstract

We propose a novel strategy to probe feebly-interacting particles (FIPs) by exploiting the dense, confined circumstellar medium (CSM) surrounding core-collapse supernovae (CCSNe). FIPs produced in the proto-neutron star can deposit substantial visible energy into the CSM via decay prior to the shock breakout from the progenitor star. This energy injection heats and ionizes the CSM, establishing a FIP-induced photosphere that generates distinctive precursor blackbody emission. Using early-time observations of SN 2023ixf, we translate the non-detection of excessive precursor luminosity into stringent new constraints on MeV-scale dark photons as an exemplary model. Our results significantly extend existing CCSN bounds and exclude previously unexplored regions of parameter space. We further demonstrate that the FIP-induced dust sublimation offers robust diagnostics for future Galactic SNe, opening a new avenue to explore the dark sector.

Figures (10)

• Figure 1: Schematic plot showing FIPs ($X$) from the PNS depositing energy into the CSM, forming a new photosphere in dense CSM. The same FIP heating also leads to dust sublimation at the outer CSM, preventing obscuration of the light from the FIP-induced photosphere.
• Figure 2: CSM density profile from Ref. Zimmerman:2023mls (blue line) features a dense region for $r \lesssim 2\times 10^{14}$ cm followed by a transition to the outer dilute region. The red line shows the temperature profile following DP energy deposition for the benchmark $(\varepsilon, m_{\gamma'})$. The dashed orange line denotes the DP-induced photosphere at $r_{\rm ph}\simeq 1.4\times 10^{14}$ cm and $T_{\rm ph}\simeq 5800$ K. Estimates show that the CSM reaches the temperature profile shown by the red line in less than $\sim 1000$ s (see EM).
• Figure 3: The solid red contour indicates the parameter that violates Eq. \ref{['eq:L_BB_constraint']} and the solid black curve marks $T|_{r=10^{15}\,{\rm cm}}>3000$ K. The red-shaded region is robustly excluded. Gray-shaded regions are existing SN constraints adapted from Ref. Caputo:2025avc.
• Figure 4: The spectral-averaged energy deposition efficiency $\bar{\eta}$ (red) and energy deposition time $\bar{t}_{\rm dep}$ (blue) as functions of $r$ for CSM density profile shown in Fig. \ref{['fig:DensityTprofile']}. Two different values of $\varepsilon=10^{-13}$ (solid) and $\varepsilon=10^{-12}$ (dashed) are illustrated. Both assume $m_{\gamma'}=10$ MeV$/c^2$.
• Figure 5: DP heating rate $\dot{q}_{\rm heat}$ (red) for benchmark $(\varepsilon, m_{\gamma'}) = (1.5\times 10^{-13}\,,20\,{\rm MeV}/c^2)$ and the radiative cooling rates $|\dot{q}_{\rm cool}|$ for $T=12800$ K (green) and 6000 K (blue); see text for details.