EDP Sciences
Free access
Volume 390, Number 3, August II 2002
Page(s) L31 - L34
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20020939

A&A 390, L31-L34 (2002)
DOI: 10.1051/0004-6361:20020939


Nucleosynthesis in $\gamma-$ray bursts outflows

M. Lemoine

Institut d'Astrophysique de Paris, GReCO, CNRS, 98 bis boulevard Arago, 75014 Paris, France

(Received 1 April 2002 / Accepted 19 June 2002)

It is shown that fusion of neutrons and protons to 4He nuclei occurs in $\gamma-$ray burst outflows in a process similar to big-bang nucleosynthesis in the early Universe. Only the surviving free neutrons can then decouple kinematically from the charged fluid so that the multi-GeV neutrino signal predicted from inelastic nuclear n-p collisions is significantly reduced. It is also argued that a sizeable fraction of ultra-high energy cosmic rays accelerated in $\gamma-$ray bursts should be 4He nuclei.

Key words: nucleosynthesis - gamma rays: bursts

© ESO 2002