Gamma-ray emission from molecular clouds illuminated by local young massive stellar clusters and detection prospects with current and next generation instruments

Abstract

Cosmic ray acceleration up to PeV energies has been suggested to take place in massive and young stellar clusters. The formation of a strong termination shock sustained by the collective action of stellar winds in a compact cluster offers a promising location where efficient particle acceleration might take place. The subsequent hadronic interactions of these particles result into gammaray production: in particular, if dense clouds are located within and around clusters, enhanced emission is expected. Within a scenario of particle acceleration at the cluster wind termination shock, we compute the emerging gamma-ray signal from molecular clouds illuminated by stellar clusters within the Milky Way. For this purpose, we adopt the Miville-Deschenes cloud catalog based on the Dame CO survey and astrometric observations of stellar clusters by GAIA. We further evaluate detection prospects of the gamma-ray flux with the Cherenkov Telescope Array (CTA) and the Large High Altitude Air Shower Observatory (LHAASO).

ICRC 2023 Rapporteur: Status of the Gamma-ray Astronomy field

“…Since several years there has been an increase interest to investigate the origin of their VHE 𝛾-ray emission through spectral and morphological studies. There are several models manage to get particles up to PeV energies [60,61] and prospects to search for their signatures [62] not only in gamma rays, but also in neutrinos. For sources like the Cygnus Cocoon [63] it was shown that synchrotron emission limits the lepton contribution at the highest energies to be less than 25% emission beyond PeV in LHAASO data [64].…”