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# Study of radio waves signals of dark matter by Gravitating systems

 Grant number: 18/21532-4 Support type: Research Grants - Visiting Researcher Grant - Brazil Duration: March 01, 2019 - February 29, 2020 Field of knowledge: Physical Sciences and Mathematics - Astronomy Principal researcher: Oswaldo Duarte Miranda Grantee: Oswaldo Duarte Miranda Visiting researcher: Elaine Cristina Ferreira Silva Fortes Visiting researcher institution: Universidade Federal do Pampa (Unipampa), Brazil Home Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia e Inovações (Brasil). São José dos Campos , SP, Brazil

Abstract

The fact that Dark Matter interacts very weakly to Standard Model implies in many difficulties in searching for it. Therefore, any situation which could put in evidence DM signatures is of great interest. The interactions between DM and SM particles are proportional to the density of the particle it interacts with. So, this suggests that we could study DM matter presence nearby astronomical objects where the gravitational force is very strong like White Dwarfs, Neutron Stars and Black holes. Signals of dark matter candidates could be detected through annihilation or decay of them in cosmic rays fluxes, photons fluxes and neutrinos fluxes in energy ranges where possibly the signal produced by dark matter exceeds the signal of the background of ordinary astrophysical processes. So, an interesting point is the combined study of these fluxes coming from strong gravitating objects and the comparison of the typical spectrum of them with the spectrum produced by the candidate. Between the promising study strategies, we highlight the secondary emissions, produced by the interactions of relativistic electron / positron resulting from the annihilation of dark matter. These emissions can be manifested through: 1) radio waves of electron and positrons synchrotron radiation, 2) $\gamma$-rays due to Compton scattering and 3) $\gamma$ rays due to bremsstrahlung processes.The combination of $\gamma$-rays and radio waves can give interesting clues trying to evidence DM. The observation by Fermi-LAT telescope have indicated the existence of an excess of $\gamma$-ray flux above the expected signal of cosmic rays interacting with the interstellar gas. This flux seems to extend over the region of the galactic center and has a peak energy of 1 -3 GeV, and one of its strong interpretation suggests as possible explanation the annihilation of dark matter particles. Besides highlighting the $\gamma$-ray excess, Fermi-LAT also discovered the globular cluster 47 Tuc to be $\gamma$-ray bright. Observations of Radio and X-rays were used to place limits on the mass of a central black hole of mass $\sim$ 2300 M$_\odot$ inhabiting with 47 Tuc. This results reveals a great opportunity to deeply study DM nearby this black hole and its possible $\gamma$-ray signals from annihilation and constraints. Such combined studies of secondary signals in strong gravitating body are the main theme of this proposed project. (AU)