Research Division Seminar
Lighting up the sky: What gamma rays reveal about supernova remnant shocks (and shocks in general)
Abstract
Over the past decade, gamma-ray observations from space-based instruments such as Fermi-LAT and ground-based arrays including H.E.S.S., MAGIC, and VERITAS have provided an increasingly detailed view of supernova remnants (SNRs). Several dozen SNRs have now been detected across the GeV–TeV energy range, revealing a diverse population shaped by their surrounding environments and evolutionary stages. The catalog of gamma-ray bright remnants continues to expand with new discoveries. Observations by HAWC and LHAASO have even identified a few Galactic PeVatron candidates, although a direct link to individual SNRs remains under investigation.
Beyond isolated remnants, gamma-ray detections from novae, as well as from star-forming regions and stellar clusters, underscore the ubiquity of shock-powered emission in explosive and turbulent environments. In particular, the collective action of multiple supernovae and stellar winds within massive star-forming regions appears capable of sustaining efficient particle acceleration, potentially bridging the gap between classical SNR shocks and Galactic PeVatrons. This review highlights recent gamma-ray results that provide new insight into the radiative signatures, acceleration efficiency, and energetic processes associated with shocks in both isolated and collective astrophysical systems.
About the talk
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About the speaker
Marianne Lemoine-Goumard is research director in the Astroparticles group of the Centre d’Etudes Nucléaires de Bordeaux Gradignan (CENBG, CNRS / University of Bordeaux). She is a specialist in high-energy astrophysics and is particularly interested in the most violent phenomena in the Universe, including supernova remnants, pulsars and their nebulae, and their role in the acceleration process of cosmic rays.
After studying at the École Centrale de Lille and Paris, she completed a thesis at the Leprince-Ringuet Laboratory at the Ecole Polytechnique. For her thesis, defended in 2006, Marianne Lemoine-Goumard was awarded the Thesis Prize of the Ecole Polytechnique, as well as the Daniel Guinier Prize of the French Physical Society. She then joined the CENBG the same year, where she continued her research on cosmic rays from the H.E.S.S. experiment, but also with data from the Fermi satellite. At the MPIK, she continues her work on extended gamma-ray sources and on shaping future instruments and observations in the field. The Alexander von Humboldt Foundation honoured Prof. Marianne Lemoine-Goumard with the Friedrich Wilhelm Bessel Research Award 2023. More recently, she was nominated last week to receive the CNRS silver medal in 2026.