| Title: |
LMC N132D: a mature supernova remnant with a power-law gamma-ray spectrum extending beyond 8 TeV |
| Authors: |
Abdalla, H; Aharonian, F; Benkhali, FA; Anguner, EO; Arcaro, C; Armand, C; Armstrong, T; Ashkar, H; Backes, M; Baghmanyan, V; Martins, VB; Barnacka, A; Barnard, M; Batzofin, R; Becherini, Y; Berge, D; Bernloehr, K; Bi, B; Boettcher, M; Boisson, C; Bolmont, J; de Lavergne, MDB; Breuhaus, M; Brose, R; Brun, F; Bulik, T; Bylund, T; Cangemi, F; Caroff, S; Casanova, S; Catalano, J; Chambery, P; Chand, T; Chen, A; Cotter, G; Curylo, M; Mbarubucyeye, JD; Davids, ID; Davies, J; Devin, J; Djannati-Atai, A; Dmytriiev, A; Donath, A; Doroshenko, V; Dreyer, L; Du Plessis, L; Duffy, C; Egberts, K; Einecke, S |
| Contributors: |
Collaboration, H.E.S.S. |
| Publisher Information: |
EDP Sciences |
| Publication Year: |
2022 |
| Collection: |
Oxford University Research Archive (ORA) |
| Description: |
Context Supernova remnants (SNRs) are commonly thought to be the dominant sources of Galactic cosmic rays up to the knee of the cosmic-ray spectrum at a few PeV. Imaging Atmospheric Cherenkov Telescopes have revealed young SNRs as very-high-energy (VHE, >100 GeV) gamma-ray sources, but for only a few SNRs the hadronic cosmic-ray origin of their gamma-ray emission is indisputably established. In all these cases, the gamma-ray spectra exhibit a spectral cutoff at energies much below 100 TeV and thus do not reach the PeVatron regime. Aims: The aim of this work was to achieve a firm detection for the oxygen-rich SNR LMC N132D in the VHE gamma-ray domain with an extended set of data, and to clarify the spectral characteristics and the localization of the gamma-ray emission from this exceptionally powerful gamma-ray-emitting SNR. Methods: We analyzed 252 h of High Energy Stereoscopic System (H.E.S.S.) observations towards SNR N132D that were accumulated between December 2004 and March 2016 during a deep survey of the Large Magellanic Cloud, adding 104 h of observations to the previously published data set to ensure a > 5σ detection. To broaden the gamma-ray spectral coverage required for modeling the spectral energy distribution, an analysis of Fermi-LAT Pass 8 data was also included. Results: We unambiguously detect N132D at VHE with a significance of 5.7σ. We report the results of a detailed analysis of its spectrum and localization based on the extended H.E.S.S. data set. The joint analysis of the extended H.E.S.S and Fermi-LAT data results in a spectral energy distribution in the energy range from 1.7 GeV to 14.8 TeV, which suggests a high luminosity of N132D at GeV and TeV energies. We set a lower limit on a gamma-ray cutoff energy of 8 TeV with a confidence level of 95%. The new gamma-ray spectrum as well as multiwavelength observations of N132D when compared to physical models suggests a hadronic origin of the VHE gamma-ray emission. Conclusions: SNR N132D is a VHE gamma-ray source that shows a spectrum ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1051/0004-6361/202141486 |
| Availability: |
https://doi.org/10.1051/0004-6361/202141486; https://ora.ox.ac.uk/objects/uuid:20099bea-3978-4a8d-bf70-c26e71237b59 |
| Rights: |
info:eu-repo/semantics/embargoedAccess |
| Accession Number: |
edsbas.D00C2729 |
| Database: |
BASE |