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1. Nucleosynthesis signatures of neutrino-driven winds from proto-neutron stars: a perspective from chemical evolution models

   https://doi.org/10.1093/mnras/stab2828  

   Vincenzo, Fiorenzo ; Thompson, Todd A ; Weinberg, David H ; Griffith, Emily J ; Johnson, James W ; Johnson, Jennifer A ( October 2021 , Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We test the hypothesis that the observed first-peak (Sr, Y, Zr) and second-peak (Ba) s-process elemental abundances in low-metallicity Milky Way stars, and the abundances of the elements Mo and Ru, can be explained by a pervasive r-process contribution originating in neutrino-driven winds from highly magnetic and rapidly rotating proto-neutron stars (proto-NSs). We construct chemical evolution models that incorporate recent calculations of proto-NS yields in addition to contributions from asymptotic giant branch stars, Type Ia supernovae, and two alternative sets of yields for massive star winds and core-collapse supernovae. For non-rotating massive star yields from either set, models without proto-NS winds underpredict the observed s-process peak abundances by 0.3–$1\, \text{dex}$ at low metallicity, and they severely underpredict Mo and Ru at all metallicities. Models incorporating wind yields from proto-NSs with spin periods P ∼ 2–$5\, \text{ms}$ fit the observed trends for all these elements well. Alternatively, models omitting proto-NS winds but adopting yields of rapidly rotating massive stars, with vrot between 150 and $300\, \text{km}\, \text{s}^{-1}$, can explain the observed abundance levels reasonably well for [Fe/H] < −2. These models overpredict [Sr/Fe] and [Mo/Fe] at higher metallicities, but with a tuned dependence of vrot on stellar metallicity they might achieve an acceptable fit at all [Fe/H]. If many proto-NSs are born with strong magnetic fields and short spin periods, then their neutrino-driven winds provide a natural source for Sr, Y, Zr, Mo, Ru, and Ba in low-metallicity stellar populations. Conversely, spherical winds from unmagnetized proto-NSs overproduce the observed Sr, Y, and Zr abundances by a large factor. 

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2. Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects

   https://doi.org/10.1007/JHEP08(2020)030  

   Coloma, Pilar ; Esteban, Ivan ; Gonzalez-Garcia, M.C. ; Menéndez, Javier ( August 2020 , Journal of High Energy Physics)

   null (Ed.)
3. Simulating the neutrino flux from the Spallation Neutron Source for the COHERENT experiment

   https://doi.org/10.1103/PhysRevD.106.032003  

   Akimov, D. ; An, P. ; Awe, C. ; Barbeau, P. S. ; Becker, B. ; Belov, V. ; Bernardi, I. ; Blackston, M. A. ; Bock, C. ; Bolozdynya, A. ; et al ( August 2022 , Physical Review D)
4. Jet launching from binary neutron star mergers: Incorporating neutrino transport and magnetic fields

   https://doi.org/10.1103/PhysRevD.105.104028  

   Sun, Lunan ; Ruiz, Milton ; Shapiro, Stuart L. ; Tsokaros, Antonios ( May 2022 , Physical Review D)
5. Neutrino emission from binary neutron star mergers: characterising light curves and mean energies

   https://doi.org/10.1140/epja/s10050-022-00743-5  

   Cusinato, Marco ; Guercilena, Federico Maria ; Perego, Albino ; Logoteta, Domenico ; Radice, David ; Bernuzzi, Sebastiano ; Ansoldi, Stefano ( May 2022 , The European Physical Journal A)

   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 resultingr-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$$10^{53}{\hbox {erg}~{\hbox {s}}^{-1}}$$${10}^{53}\text{erg}{\text{s}}^{-1}$) 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.

    

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