Neutrinos and Nucleosynthesis from Black Hole Accretion Disks Gail McLaughlin North Carolina State University 1 Neutrino Astrophysics • What do neutrinos do in astrophysical environments? • What do neutrinos in a core collapse supernova do? • What do neutrinos in a gamma ray burst do? • What do neutrinos in a compact object merger do? Nuclear Astrophysics • What is the origin of the elements? • Where are the heaviest elements made? • What elements are made in compact object mergers/ stellar explosions? 2 Black Hole - Accretion Disk Neutrinos • black hole - accretion disks form in some supernovae, compact object mergers and gamma ray bursts • νs important for disk energetics • νs in principle are detectable • νs may help power gamma ray bursts • νs influence nucleosynthesis 3 Explosions of Massive Stars: What’s happening at the Center? black hole, jet shock outflow neutrinos accretion disk proto neutron star core Standard core core collapse SN Accretion disk SN, compact object merger, gamma ray burst 4 Explosions of Massive Stars: Hydrodynamical Calculations Core core collapse SN Gamma ray burst jet Blondin & Mezzacappa (2007) Morsony, Lazzati, & Begelman (2007) 5 Explosions of Massive Stars: Where is the nuclear-neutrino physics? neutrino nucleosynthesis oscillations black hole, jet shock nucleosynthesis outflow neutrino oscillations neutrinos accretion disk neutrino neutrino nuclear physics scattering scattering of the disk nuclear physics proto neutron & emission star core & emission of core Standard core core collapse SN Accretion disk SN, compact object merger, gamma ray burst 6 Neutrino surfaces: GCM & R. Surman 2006 7 Comparison of Spectra: PNS and low accretion rate disks Electron neutrinos and antineutrinos from disks have similar energies to neutrinos from protoneutron stars. GCM & R Surman 2006 8 Compact Object Merger Models • Neutron star and black hole spiral in • Create an accretion disk around a black hole Surman et al 2009 9 Neutrino Detection Extreme: What if the next direct supernova neutrino detection is not a “traditional” core collapse supernova? Rates: • Regular supernova ∼ 7000 events, 10 seconds ˙ • Accretion Disk of M = 0.1M/M⊙, 1400 events, 10 seconds • Black Hole - Neutron Star merger, 9000 events, 0.01 seconds For events at 10 kpc. Caballero et al 2009 10 Nucleosynthesis in Hot Outflows Three types of environments • proto-neutron star supernovae • accretion disk supernovae • compact object mergers Several important types of nucleosynthesis • r-process • p-process • 56Ni - an ingredient in light curves 11 Neutrino - Nucleosynthesis connection If neutrinos have most of the energy in an object, they are key to determining the astrophysical conditions. Also, they determine the relative numbers of neutrons and protons... − • νe + n ↔ p + e + • ν¯e + p ↔ n + e 12 Nucleosynthesis in Hot Outflows n,p →4 He → iron peak nuclei → heavier nuclei 13 Nickel in Hot Outflows n,p →4 He → iron peak nuclei → heavier nuclei Surman et al 2010 14 Neutrinos and light p-nucleosynthesis Thought to occur in supernovae and in accretion disk outflows ν-p process p-process 105 104 103 i, /Y i Y 102 101 100 40 45 50 55 60 65 70 75 80 85 90 95 100 Mass Number A Frohlich et al 2007, Kizivat et al 2010 15 Pruet et al, Surman et al 2005, 2010 Nucleosynthesis: Compact Object Merger Models • Neutrino Emission Temper- atures • Electron and Anti-electron Neutrinos Surman et al 2009 16 Hot Outflow Nucleosynthesis Black Hole Neutron Star Merger Schematic of events in outflow R-process occurs in the wind Surman et al. 2008 17 Improvements needed in the treatment of Disk Neutrinos • hydrodynamic calculations • general relativistic effects • neutrino transport • neutrino flavor transforma- tion Neutrino bending, figure by Liliana Caballero 18 Summary • Neutrinos from accretion disks have somewhat similar spectra to proto-neutron star neutrinos • Gamma ray bursts make a lot of nickel, and likely some other rare elements • Compact object mergers make the r-process in hot outflows • Neutrinos play an important role in determining the type of elements formed • More to understand about astrophysical environment and neutrinos 19.