13ª Semana Integrada do Instituto de Física de São Carlos

Radiative model reconstruction of the Galactic Center central gamma-ray source

21 de ago. de 2023 10:30

1h 30m

Salão de Eventos USP

Prêmio YPM 10h30 - 12h00

Descrição

Among all the high-energy environments of our Galaxy, the Galactic Center region is definitely the richest with HESS J1745-290 being its brightest source of γ-rays. (1) However, its origin is still unknown, and it may be related to accretion in the central black hole (Sgr A+), a wind from prolonged pulsars, or another type of source. This work aims to investigate whether the central source of γ-rays would be linked to cosmic particle accelerators, discovered in this region, capable of accelerating particles to PeV energies, called Pevatron. In this scenario, the stochastic acceleration of protons (up to PeV energies) interacting with the turbulent magnetic field in the vicinity of Sgr A+ could produce an escape flow of relativistic protons that diffuse outwards interacting with the molecular clouds that surround this region producing the observed γ-ray. (2) To explore this hypothesis, the morphology of the molecular clouds inside the central 10pc Sgr A* were modeled, as well as the production of γ-rays from the decay of $π^{0}$ that are produced through the proton-proton interaction of cosmic rays, which in the diffusion process collide with these clouds. With the elaboration of a computational code, the flux of γ-rays was calculated in two different scenarios, from a source of impulsive and continuous injection cosmic rays, and in each case a 2D image of these flows was made, obtaining different morphologies for each scenario. In the next, we will simulate the observed morphology of these two scenarios by convolving them a γ-ray telescope , such as CTA, instrument response function. We hope to be possible to infer if CTA will be able to differentiate which of the γ-ray emissivity scenarios is occurring in this region.

Referências

1 LONGAIR, M. S. High energy astrophysics. 3rd ed. Cambridge, UK: Cambridge University Press, 2011. 861 p.

2 FERRIÈRE, K. Interstellar gas within ~10 pc of Sagittarius A∗. Astronomy and Astrophysics, v. 540, p. A50-1-A50-21, Apr. 2012. DOI: http://dx.doi.org/10.1051/0004-6361/201117181.