Inhomogeneities in type Ib/c supernovae: An inverse Compton scattering origin of the X-ray emission

TL;DR

The paper suggests that inhomogeneities in type Ib/c supernovae influence observed properties and proposes inverse Compton scattering as the primary origin of early X-ray emission, challenging the synchrotron radiation model.

Contribution

It introduces the idea that inhomogeneities affect supernova observations and demonstrates that early X-ray emission is likely due to inverse Compton scattering, not synchrotron radiation.

Findings

Inhomogeneities can increase inferred shock velocities.

Broadening of spectra indicates source inhomogeneity.

X-ray emission correlates with inverse Compton scattering.

Abstract

Inhomogeneities in a synchrotron source can severely affect the conclusions drawn from observations regarding the source properties. However, their presence is not always easy to establish, since several other effects can give rise to similar observed characteristics. It is argued that the recently observed broadening of the radio spectra and/or light curves in some of the type Ib/c supernovae is a direct indication of inhomogeneities. As compared to a homogeneous source, this increases the deduced velocity of the forward shock and the observed correlation between total energy and shock velocity could in part be due to a varying covering factor. The X-ray emission from at least some type Ib/c supernovae is unlikely to be synchrotron radiation from an electron distribution accelerated in a non-linear shock. Instead it is shown that the observed correlation during the first few hundred days between the radio, X-ray and bolometric luminosities indicates that the X-ray emission is inverse Compton scattering of the photospheric photons. Inhomogeneities are consistent with equipartition between electrons and magnetic fields in the optically thin synchrotron emitting regions.