Astrophysical constraints on a possible neutrino ball at the Galactic Center

¹ Dipartimento di Fisica, Università di Lecce, and INFN, Sezione di Lecce, Via Arnesano, CP 193, 73100 Lecce, Italy
² Dipartimento di Fisica "E. R. Caianiello", Università di Salerno, and INFN, Sezione di Salerno, Via S. Allende, 84081 Baronissi (Sa), Italy

Corresponding author: F. De Paolis, Francesco.DePaolis@le.infn.it

Received: 7 February 2001
Accepted: 27 June 2001

Abstract

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 . However, the black hole hypothesis, which theoretically implies a luminosity 10⁴¹ erg s^-1, runs into problems if one takes into account that the observed luminosity, from radio to γ-ray wavelengths, is below 10³⁷ erg s^-1. 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 is ≳ 24 keV, while if keV observations cannot give a definite answer.