Speaker
Description
The recent detection of ultra-high-energy (UHE; >100 TeV) γ-rays by LHAASO has advanced our understanding of galactic particle accelerators, providing strong evidence for PeV particle acceleration. While sources such as supernova remnants (SNRs), microquasars, and young massive clusters are the main PeVatron candidates, the origin of their UHE emission remains a subject of intense debate. A compelling narrative involves accelerated particles that escape from an SNR shock and interact with nearby dense molecular clouds, producing neutral pion-decay γ-rays. However, interpreting these emissions requires a sophisticated treatment of how particles are both confined at the molecular clouds and transported through the interstellar medium considering the source-cloud distance.
In this contribution, I present a two-phase simulation model centered on SNRs as the principal engines of particle acceleration. Utilizing our remnant-shock model and the transport pipeline based on the GAMERA code, I investigate two distinct scenarios: direct source-cloud interactions governed by shock-induced adiabatic compression, and indirect cloud illumination by cosmic rays escaping from earlier evolutionary stages. This framework is applied to the W51 complex and to LHAASO J0341+5258, targeting the recent UHE detection by LHAASO. Finally, I will discuss the physical requirements for spatially resolving these complex regions, which could be achieved by next-generation IACTs such as CTAO and the ASTRI Mini-Array, and the importance of the multi-messenger and multi-frequency analysis in order to finally disentangle hadronic and leptonic γ-ray emission.
