Can a single supernova remnant account for the gamma-ray emission of G106.3+2.7?

The supernova remnant (SNR) G106.3+2.7 is a complex TeV emitting source whose emission is still poorly understood. There have been numerous discussions on its potential of being a SNR PeVatron since its gamma-ray spectra do not seem to exhibit any significant suppression in the multi-TeV range, up to ∼ 600 TeV, thereby indicating the presence of ∼ PeV particles. We studied the hypothesis in which an SNR evolving in a clumpy or cloudy environment powers the TeV gamma-ray emission detected mainly from two regions, the "head" and the "tail." We discuss the implications of such an hypothesis. We relied on simple physically motivated analytical modeling of the shock dynamics and of the content of accelerated particles and confronted it to available gamma-ray observations. We find that the current observed TeV gamma-ray emission in the head and tail regions can be accounted for by a single active SNR, with a natural hardening of the spectrum due expansion into a clumpy medium or escaping to a dense region in the tail. However, in all scenarios the broadband gamma-ray emission from the GeV range to the ≳ 100 TeV range is difficult to reconcile with a standard SNR, whether originating from a thermonuclear or a core-collapse supernova, and it instead points toward an association with the pulsar.