Deep observations of Kepler's SNR with H.E.S.S

TL;DR

Deep H.E.S.S. observations provide strong evidence of very high energy gamma-ray emission from Kepler's supernova remnant, offering insights into cosmic-ray acceleration in young supernova remnants.

Contribution

First detection of VHE gamma-ray emission from Kepler's SNR using extensive H.E.S.S. observations, advancing understanding of gamma-ray sources in young SNRs.

Findings

Detected VHE gamma-ray signal from Kepler's SNR

Extended exposure of 152 hours with H.E.S.S.

Implications for cosmic-ray acceleration in young SNRs

Abstract

Kepler's supernova remnant (SNR) which is produced by the most recent naked-eye supernova in our Galaxy is one of the best studied SNRs, but its gamma-ray detection has eluded us so far. Observations with modern imaging atmospheric Cherenkov telescopes (IACT) have enlarged the knowledge about nearby SNRs with ages younger than 500 years by establishing Cassiopeia A and Tycho's SNRs as very high energy (VHE) gamma-ray sources and setting a lower limit on the distance to Kepler's SNR. This SNR is significantly more distant than the other two and expected to be one of the faintest gamma-ray sources within reach of the IACT arrays of this generation. We report strong evidence for a VHE signal from Kepler's SNR based on deep observations of the High Energy Stereoscopic System (H.E.S.S.) with an exposure of 152 hours, including 122 hours accumulated in 2017-2020. We further discuss implications of this result for cosmic-ray acceleration in young SNRs.