2001A&A...376..853D

The nature of the massive object at the Galactic Center (Sgr A^*) is still unclear even if various observational campaigns led many authors to believe that our Galaxy hosts a super-massive black hole with mass M≃2.6x10⁶M_☉. However, the black hole hypothesis, which theoretically implies a luminosity ≃10⁴¹erg/s, runs into problems if one takes into account that the observed luminosity, from radio to γ-ray wavelengths, is below 10³⁷erg/s. In order to solve this blackness problem, alternative models have recently been proposed. In particular, it has been suggested that the Galactic Center hosts a ball made up of non-baryonic matter (e.g. massive neutrinos and anti-neutrinos) in which the degeneracy pressure of fermions balances their self-gravity. Requiring it to be consistent with all the available observations towards the Galactic Center allows us to put severe astrophysical constraints on the neutrino ball parameters. The presence of such an object in the Galactic Center may be excluded if the constituent neutrino mass m_ν is >24keV, while if m_ν≲24keV observations cannot give a definite answer.