Radio synchrotron emission from secondary electrons in interaction-powered supernovae

Abstract

Several supernovae (SNe) with an unusually dense circumstellar medium (CSM) have been recently observed at radio frequencies. Their radio emission is powered by relativistic electrons that can be either accelerated at the SN shock (primaries) or injected as a by-product (secondaries) of inelastic proton-proton collisions. We investigate the radio signatures from secondary electrons, by detailing a semi-analytical model to calculate the temporal evolution of the distributions of protons, primary and secondary electrons. With our formalism, we track the cooling history of all the particles that have been injected into the emission region up to a given time, and calculate the resulting radio spectra and light curves. For a SN shock propagating through the progenitor wind, we find that secondary electrons control the early radio signatures, but their contribution decays faster than that of primary electrons. This results in a flattening of the light curve at a given radio frequency that depends only upon the radial profiles of the CSM density and of the shock velocity, $v_0$. The relevant transition time at the peak frequency is $\sim 190K_{\mathrm{ep},-3}^{-1}{A}_{\mathrm{w},16}{\beta }_{0,-1.5}^{-2}\mathrm{d}$, where $A_{\mathrm{w}}$ is the wind mass-loading parameter, ${\beta }_0=v_0/c$ and $K_{\mathrm{ep}}$ is the electron-to-proton ratio of accelerated particles. We explicitly show that late peak times at 5 GHz (i.e., $t_{\mathrm{pk}}\gtrsim 300-1000$ d) suggest a shock wave propagating in a dense wind ($A_{\mathrm{w}}\gtrsim 10^{16}-10^{17}$ gr cm${}^{-1}$), where secondary electrons are likely to power the observed peak emission.

23 pages, 12 figures, resubmitted to MNRAS after minor revisions following referee's comments

References in corpus (24)

• Physical Properties of Wolf-Rayet Stars
• Circumstellar Emission from Type Ib and Ic Supernovae
• The origin of the positron excess in cosmic rays
• Simultaneous Acceleration of Protons and Electrons at Nonrelativistic Quasiparallel Collisionless Shocks
• Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism
• Fermi acceleration in astrophysical jets
• Are both BL Lacs and pulsar wind nebulae the astrophysical counterparts of IceCube neutrino events?
• On the Evolution of and High-Energy Emission from GHz-Peaked-Spectrum Sources
• The Evolution of Supernovae in Circumstellar Wind Bubbles II: Case of a Wolf-Rayet star
• Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. II. Firehose-Mediated Fermi Acceleration and its Dependence on Pre-Shock Conditions
• A Deep Search for Prompt Radio Emission from Thermonuclear Supernovae with the Very Large Array
• On the cosmic ray spectrum from type II Supernovae expanding in their red giant presupernova wind
• Interaction-powered supernovae: Rise-time vs. peak-luminosity correlation and the shock-breakout velocity
• Type IIn supernovae as sources of high energy astrophysical neutrinos
• Radio and X-rays From SN 2013df Enlighten Progenitors of Type IIb Supernovae
• Supernova 1996cr: SN 1987A's Wild Cousin?
• SN 2007bg: The Complex Circumstellar Environment Around One of the Most Radio-Luminous Broad-Lined Type Ic Supernovae
• Unified model for the gamma-ray emission of supernova remnants
• Novae as Tevatrons: Prospects for CTA and IceCube
• Detection of a Type IIn Supernova in Optical Follow-up Observations of IceCube Neutrino Events
• Particle-acceleration timescales in TeV blazar flares
• Imaging the Expanding Shell of SN 2011dh
• Collisionless Shocks and TeV Neutrinos before Supernova Shock Breakout from an Optically Thick Wind
• Heating from free-free absorption and the mass-loss rate of the progenitor stars to supernovae

Cited by in corpus (20)

• New Prospects for Detecting High-Energy Neutrinos from Nearby Supernovae
• High-Energy Emission from Interacting Supernovae: New Constraints on Cosmic-Ray Acceleration in Dense Circumstellar Environments
• Point-source and diffuse high-energy neutrino emission from Type IIn supernovae
• Radio Emission from Embryonic Super-Luminous Supernova Remnants
• Is the high-energy neutrino event IceCube-200530A associated with a hydrogen-rich superluminous supernova?
• Interacting supernovae as high-energy multimessenger transients
• Radio Emission from Supernovae in the Very Early Phase: Implications for the Dynamical Mass Loss of Massive Stars
• Radiative Acceleration of Dense Circumstellar Material in Interacting Supernovae
• Detecting High-Energy Neutrino Minibursts from Local Supernovae with Multiple Neutrino Observatories
• Radio Analysis of SN 2004C Reveals an Unusual CSM Density Profile as a Harbinger of Core Collapse
• Optically Informed Searches of High-Energy Neutrinos from Interaction-Powered Supernovae
• A hadronic emission model for black hole-disc impacts in the blazar OJ 287
• Neutrino Emission from Luminous Fast Blue Optical Transients
• New constraints on the gamma-ray and high energy neutrino fluxes from the circumstellar interaction of SN 2023ixf
• Multi-wavelength View of the Type IIn Zoo: Optical to X-ray Emission Model of Interaction-Powered Supernovae
• Radio emission from colliding outflows in high-mass X-ray binaries with strongly magnetized neutron stars
• Radio Emission from Ultra-stripped Supernovae as Diagnostics for Properties of the Remnant Double Neutron Star Binaries
• Secondary-electron radiation accompanying hadronic GeV-TeV gamma-rays from supernova remnants
• A relook at the GZK Neutrino-Photon Connection: Impact of Extra-galactic Radio Background & UHECR properties
• High-energy Neutrino Predictions for T Coronae Borealis: Probing Particle Acceleration in Novae