Alumni 2024

    Francesco Conte   (Italy)                                                                                                               01.02.2024

Gamma-ray emission and absorption in the inner few parsecs of the Galactic Centre  ( thesis pdf, 15 MB)

Located 8 kpc away, the Galactic Centre is a rich environment for observing non-thermal phenomena such as a supermassive black hole, potential dark matter accumulations, supernova remnants, pulsar wind nebulae, clustered massive stars, and many more. It is a key target for both operational and next-generation TeV observatories like H.E.S.S., MAGIC, and CTA. Current telescopes, limited by a full-width half-maximum of 5 arcminutes, struggle to pinpoint the nature of gamma-ray sources amidst the Galactic Centre’s complexity. UV/visible observations are also compromised due to dust absorption and infrared re-emission. However, this study leverages the infrared radiation’s ability to absorb high-energy photons, using a model of the infrared field for spatial and spectral gamma-ray analyses. In this thesis I present the first 3D model for the infrared radiation field in the inner few parsecs. By studying the high-energy absorption, I find that if the central gamma-ray source and the large scale gamma-ray emission share the same cosmic-ray accelerator, then the central emitter is a ring of outer radius 2.5 pc that CTA will see as an extended source. In that case, the diffuse gamma-ray emission is expected to show a turn-off around 20 TeV rather than a power-law to 100 TeV.

Supervisor:    Richard Tuffs  (MPIK)