VHE gamma-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S

TL;DR

This paper reports on H.E.S.S. observations of two young, synchrotron-dominated supernova remnants, G1.9+0.3 and G330.2+1.0, aiming to detect very-high-energy gamma-ray emission and understand particle acceleration.

Contribution

First VHE gamma-ray observational analysis of G1.9+0.3 and G330.2+1.0, providing insights into their particle acceleration mechanisms.

Findings

No significant VHE gamma-ray emission detected from either SNR.

Results place constraints on particle acceleration models in young SNRs.

Implications for future observations and theoretical modeling of SNRs.

Abstract

Supernova remnants (SNRs) are widely considered to be accelerators of cosmic rays (CR). They are also expected to produce very-high-energy (VHE; $E > 100$ GeV) gamma rays through interactions of high-energy particles with the surrounding medium and photon fields. They are, therefore, promising targets for observations with ground-based imaging atmospheric Cherenkov telescopes like the H.E.S.S. telescope array. VHE gamma-ray emission has already been discovered from a number of SNRs, establishing them as a prominent source class in the VHE domain. Of particular interest are the handful of SNRs whose X-ray spectra are dominated by non-thermal synchrotron emission, such as the VHE gamma-ray emitters RX J0852.0-4622 (Vela Jr.) and RX J1713-3946. The shell-type SNRs G1.9+0.3 and G330.2+1.0 also belong to this subclass and are further notable for their young ages ($\leq 1$ kyr), especially G1.9+0.3, which was recently determined to be the youngest SNR in the Galaxy ($\sim100$ yr). These unique characteristics motivated investigations with H.E.S.S. to search for VHE gamma rays. The results of the H.E.S.S. observations and analyses are presented, along with implications for potential particle acceleration scenarios.