High-energy Emission from Interacting Supernovae: New Constraints on Cosmic-Ray Acceleration in Dense Circumstellar Environments

Abstract

Supernovae (SNe) with strong interactions with circumstellar material (CSM) are promising candidate sources of high-energy neutrinos and gamma rays, and have been suggested as an important contributor to Galactic cosmic rays beyond 10 15 eV. Taking into account the shock dissipation by a fast velocity component of SN ejecta, we present comprehensive calculations of the non-thermal emission from SNe powered by shock interactions with a dense wind or CSM. Remarkably, we consider electromagnetic cascades in the radiation zone and subsequent attenuation in the pre-shock CSM. A new time-dependent phenomenological prescription provided by this work enables us to calculate gamma-ray, hard X-ray, radio, and neutrino signals, which originate from cosmic rays accelerated by the diffusive shock acceleration mechanism. We apply our results to SN IIn 2010jl and SN Ib/IIn 2014C, for which the model parameters can be determined from the multi-wavelength data. For SN 2010jl, the more promising case, by using the the latest Fermi Large Area Telescope (LAT) Pass 8 data release, we derive new constraints on the cosmic-ray energy fraction, ǫ p ∼ < 0.05 − 0.1. We also find that the late-time radio data of these interacting SNe are consistent with our model. Further multimessenger and multi-wavelength observations of nearby interacting SNe should give us new insights into the diffusive shock acceleration in dense environments as well as pre-SN mass-loss mechanisms.

Multimessenger tests of cosmic-ray acceleration in radiatively inefficient accretion flows

“…For the injection terms from pp interactions, see Ref. [160]. We plot proton-induced cascade gamma-ray spectra in Figure 3.…”

High-Energy Multimessenger Transient Astrophysics

“…Detection of high-energy emission from extragalactic supernovae requires stronger CSM interactions, which can be expected for Type IIn supernovae (125,126). Searches for GeV-TeV γ -ray emission have also been performed, but the constraints are still consistent with theoretical predictions (127)(128)(129). Some Type Ibc supernovae with a relativistic velocity component-transrelativistic supernovae that are often associated with low-luminosity GRBs-can also be neutrino and γ -ray emitters owing to interactions with the CSM (see References 130 and 131 for more details).…”

Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos

“…These pairs also emit gamma-rays, and electromagnetic cascades are initiated. We calculate the cascade emission by solving the kinetic equations of electron/positron pairs and photons 95,96 :…”