Neutrinos and Nucleosynthesis from Black Hole Accretion Disks. Gail McLaughlin North Carolina State University

Transcription

1 Neutrinos and Nucleosynthesis from Black Hole Accretion Disks Gail McLaughlin North Carolina State University 1

2 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

3 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

4 Explosions of Massive Stars: What s happening at the Center? shock black hole, jet outflow neutrinos accretion disk proto neutron star core Standard core core collapse SN Accretion disk SN, compact object merger, gamma ray burst 4

5 Explosions of Massive Stars: Hydrodynamical Calculations Core core collapse SN Blondin & Mezzacappa (2007) Gamma ray burst jet Morsony, Lazzati, & Begelman (2007) 5

6 Explosions of Massive Stars: Where is the nuclear-neutrino physics? nucleosynthesis shock neutrino oscillations nucleosynthesis black hole, jet outflow neutrino oscillations neutrinos nuclear physics of core proto neutron star core neutrino scattering & emission accretion disk nuclear physics of the disk neutrino scattering & emission Standard core core collapse SN Accretion disk SN, compact object merger, gamma ray burst 6

7 Neutrino surfaces: GCM & R. Surman

8 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

9 Compact Object Merger Models Neutron star and black hole spiral in Create an accretion disk around a black hole Surman et al

10 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 Ṁ = 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

11 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 56 Ni - an ingredient in light curves 11

12 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... ν e + n p + e ν e + p n + e + 12

13 Nucleosynthesis in Hot Outflows n,p 4 He iron peak nuclei heavier nuclei 13

14 Nickel in Hot Outflows n,p 4 He iron peak nuclei heavier nuclei Surman et al

15 Neutrinos and light p-nucleosynthesis Thought to occur in supernovae and in accretion disk outflows ν-p process p-process Yi/Yi, Mass Number A Frohlich et al 2007, Kizivat et al Pruet et al, Surman et al 2005, 2010

16 Nucleosynthesis: Compact Object Merger Models Neutrino Emission Temperatures Electron and Anti-electron Neutrinos Surman et al

17 Hot Outflow Nucleosynthesis Black Hole Neutron Star Merger Schematic of events in outflow Surman et al R-process occurs in the wind

18 Improvements needed in the treatment of Disk Neutrinos hydrodynamic calculations general relativistic effects neutrino transport neutrino flavor transformation Neutrino bending, figure by Liliana Caballero 18

19 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