https://doi.org/10.1140/epja/s10050-022-00743-5
Regular Article - Theoretical Physics
Neutrino emission from binary neutron star mergers: characterising light curves and mean energies
1
Dipartimento di Fisica, Università di Trieste, Via A. Valerio 2, 34127, Trieste, Italy
2
INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, via Sommarive 14, 38123, Trento, Italy
3
Dipartimento di Fisica, Università di Trento, Via Sommarive 14, 38123, Trento, Italy
4
Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo, 3, 56127, Pisa, Italy
5
INFN, Sezione di Pisa, Largo B. Pontecorvo, 3, 56127, Pisa, Italy
6
Institute for Gravitation and the Cosmos, The Pennsylvania State University, 16802, University Park, PA, USA
7
Department of Physics, The Pennsylvania State University, 16802, University Park, PA, USA
8
Department of Astronomy and Astrophysics, The Pennsyvlania State University, 16802, University Park, PA, USA
9
Theoretisch-Physikalisches Institut, Friedrich-Schiller Universität Jena, 07743, Jena, Germany
10
Dipartimento di Scienze Matematiche, Informatiche e Fisiche, Univerità degli Studi di Udine, via delle Scienze 206, 33100, Udine, Italy
Received:
21
November
2021
Accepted:
5
May
2022
Published online:
23
May
2022
Neutrinos are copiously emitted by neutron star mergers, due to the high temperatures reached by dense matter during the merger and its aftermath. Neutrinos influence the merger dynamics and shape the properties of the ejecta, including the resulting r-process nucleosynthesis and kilonova emission. In this work, we analyse neutrino emission from a large sample of binary neutron star merger simulations in Numerical Relativity, covering a broad range of initial masses, nuclear equation of state and viscosity treatments. We extract neutrino luminosities and mean energies, and compute quantities of interest such as the peak values, peak broadnesses, time averages and decrease time scales. We provide a systematic description of such quantities, including their dependence on the initial parameters of the system. We find that for equal-mass systems the total neutrino luminosity (several 
) decreases as the reduced tidal deformability increases, as a consequence of the less violent merger dynamics. Similarly, tidal disruption in asymmetric mergers leads to systematically smaller luminosities. Peak luminosities can be twice as large as the average ones. Electron antineutrino luminosities dominate (initially by a factor of 2-3) over electron neutrino ones, while electron neutrinos and heavy flavour neutrinos have similar luminosities. Mean energies are nearly constant in time and independent on the binary parameters. Their values reflect the different decoupling temperature inside the merger remnant. Despite present uncertainties in neutrino modelling, our results provide a broad and physically grounded characterisation of neutrino emission, and they can serve as a reference point to develop more sophisticated neutrino transport schemes.
© The Author(s) 2022. corrected publication 2022
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