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Neutrinos and the stars

Neutrinos and the stars. Supernova Neutrinos. Georg Raffelt, MPI for Physics Lectures at the Topical Seminar Neutrino Physics & Astrophysics 17 - 21 Sept 2008, Beijing, China. Sanduleak - 69 202. Supernova 1987A 23 February 1987. Tarantula Nebula. Large Magellanic Cloud Distance 50 kpc

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Neutrinos and the stars

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  1. Neutrinos and the stars Supernova Neutrinos Georg Raffelt, MPI for Physics Lectures at the Topical Seminar Neutrino Physics & Astrophysics 17-21 Sept 2008, Beijing, China

  2. Sanduleak -69 202 Supernova 1987A23 February 1987 Tarantula Nebula Large Magellanic Cloud Distance 50 kpc (160.000 light years)

  3. Supernova Neutrinos 20 Jahre nach SN 1987A

  4. Crab Nebula

  5. Stellar Collapse and Supernova Explosion Main-sequence star Onion structure Helium-burning star Collapse (implosion) Hydrogen Burning Helium Burning Hydrogen Burning Degenerate iron core: r 109 g cm-3 T  1010 K MFe 1.5 Msun RFe 8000 km

  6. Stellar Collapse and Supernova Explosion Newborn Neutron Star Collapse (implosion) Explosion ~ 50 km Neutrino Cooling Proto-Neutron Star r  rnuc= 31014 g cm-3 T  30 MeV

  7. Stellar Collapse and Supernova Explosion Newborn Neutron Star ~ 50 km Gravitational binding energy Eb 3  1053 erg  17% MSUN c2 This shows up as 99% Neutrinos 1% Kinetic energy of explosion (1% of this into cosmic rays) 0.01% Photons, outshine host galaxy Neutrino Cooling Neutrino luminosity Ln 3  1053 erg / 3 sec  3  1019LSUN While it lasts, outshines the entire visible universe Proto-Neutron Star r  rnuc= 31014 g cm-3 T  30 MeV

  8. Neutrino Signal of Supernova 1987A Kamiokande-II (Japan) Water Cherenkov detector 2140 tons Clock uncertainty 1 min Irvine-Michigan-Brookhaven (US) Water Cherenkov detector 6800 tons Clock uncertainty 50 ms Baksan Scintillator Telescope (Soviet Union), 200 tons Random event cluster ~ 0.7/day Clock uncertainty +2/-54 s Within clock uncertainties, signals are contemporaneous

  9. SN 1987A Event No.9 in Kamiokande Kamiokande Detector Hirata et al., PRD 38 (1988) 448

  10. Thermonuclear vs. Core-Collapse Supernovae • Carbon-oxygen white dwarf • (remnant of • low-mass star) • Accretes matter • from companion • Degenerate iron core • of evolved massive star • Accretes matter • by nuclear burning • at its surface Nuclear burning of C and O ignites  Nuclear deflagration (“Fusion bomb” triggered by collapse) Collapse to nuclear density Bounce & shock Implosion  Explosion Powered by nuclear binding energy Powered by gravity Gain of nuclear binding energy ~ 1 MeV per nucleon Gain of gravitational binding energy ~ 100 MeV per nucleon 99% into neutrinos Thermonuclear (Type Ia) Core collapse (Type II, Ib/c) Chandrasekhar limit is reached - MCh 1.5 Msun (2Ye)2 C O L L A P S E S E T S I N Comparable “visible” energy release of ~ 3 1051erg

  11. Supernova Neutrinos 20 Jahre nach SN 1987A Explosion Mechanism for Core-Collapse SNe

  12. Collapse and Prompt Explosion Velocity Density Movies by J.A.Font, Numerical Hydrodynamics in General Relativity http://www.livingreviews.org Supernova explosion primarily a hydrodynamical phenomenon

  13. Why No Prompt Explosion? Undissociated Iron Collapsed Core Shock Wave Dissociated Material (n, p, e, n) • 0.1 Msun of iron has a • nuclear binding energy •  1.7  1051 erg • Comparable to • explosion energy • Shock wave forms • within the iron core • Dissipates its energy • by dissociating the • remaining layer of iron

  14. Neutrinos to the Rescue Neutrino heating increases pressure behind shock front Picture adapted from Janka, astro-ph/0008432

  15. Supernova Delayed Explosion Scenario

  16. Standing Accretion Shock Instability (SASI) Mezzacappa et al., http://www.phy.ornl.gov/tsi/pages/simulations.html

  17. Gravitational Waves from Core-Collapse Supernovae Asymmetric neutrino emission Bounce Convection Müller, Rampp, Buras, Janka, & Shoemaker, “Towards gravitational wave signals from realistic core collapse supernova models,” astro-ph/0309833 The gravitational-wave signal from convection is a generic and dominating feature

  18. Supernova Neutrinos 20 Jahre nach SN 1987A Some Particle-Physics Lessons from SN 1987A

  19. Neutrino Mass Sensitivity by Signal Dispersion Time-of-flight delay of massive neutrinos SN 1987A (50 kpc) E  20 MeV, Dt  10 s Simple estimate or detailed maximum likelihood analysis give similar results mn≲ 20 eV Future Galactic SN at 10 kpc (Super-K) Rise-time of signal ~ 10 ms (Totani, PRL 80:2040, 1998) mn~ 3 eV Full signal (Nardi & Zuluaga, NPB 731:140, 2005) mn~ 1 eV With late black-hole formation Cutoff “infinitely” fast (Beacom et al., PRD 63:073011, 2001) mn~ 2 eV Future SN in Andromeda (Megatonne) D  750 kpc, Dt  10 s few tens of events mn~ 1-2 eV

  20. Early Lightcurve of SN 1987A Expected bolometric brightness evolution Expected visual brightness evolution Neutrinos several hours before light Adapted from Arnett et al., ARAA 27 (1989)

  21. Do Neutrinos Gravitate? Neutrinos arrive a few hours earlier than photons  Early warning (SNEWS) SN 1987A: Transit time for photons and neutrinos equal to within ~ 3h Shapiro time delay for particles moving in a gravitational potential Longo, PRL 60:173,1988 Krauss & Tremaine, PRL 60:176,1988 Equal within ~ 1 - 4 10-3 • Proves directly that neutrinos respond to gravity in the usual way • because for photons gravitational lensing already proves this point • Cosmological limits DNn≲ 1 much worse test of neutrino gravitation • Provides limits on parameters of certain non-GR theories of gravitation • Photons likely obscured for next galactic SN, so this result probably • unique to SN 1987A

  22. The Energy-Loss Argument Volume emission of novel particles Emission of very weakly interacting particles would “steal” energy from the neutrino burst and shorten it. (Early neutrino burst powered by accretion, not sensitive to volume energy loss.) Neutrino diffusion Late-time signal most sensitive observable Neutrino sphere SN 1987A neutrino signal

  23. Axion Bounds [GeV] fa 103 106 109 1012 ma keV eV meV meV Experiments Tele scope CAST Direct search ADMX Too much hot dark matter Too much cold dark matter Globular clusters (a-g-coupling) Too many events Too much energy loss SN 1987A (a-N-coupling)

  24. Sterile Neutrinos Average scattering rate in SN core involving ordinary left-handed neutrinos Electron neutrino appears as sterile neutrino in ½ sin2(2Qes) of all cases Active-sterile mixing To avoid complete energy loss in ~ 1 s sin2(2Qes) ≲ 3  10-10

  25. Sterile Neutrino Limits See also: Maalampi & Peltoniemi: Effects of the 17-keV neutrino in supernovae PLB 269:357,1991 Hidaka & Fuller: Dark matter sterile neutrinos in stellar collapse: alteration of energy/lepton number transport and a mechanism for supernova explosion enhancement PRD 74:125015,2006

  26. Supernova 1987A Limit on Large Extra Dimensions SN core emits large flux of KK gravity modes by nucleon-nucleon bremsstrahlung Large multiplicity of modes RT ~ 1011 for R ~ 1 mm, T ~ 30 MeV Cullen & Perelstein, hep-ph/9904422 Hanhart et al., nucl-th/0007016 SN 1987A energy-loss argument: R < 1 mm, M > 9 TeV (n = 2) R < 1 nm, M > 0.7 TeV (n = 3) Originally the most restrictive limit on such theories, except for cosmological arguments

  27. Supernova Neutrinos 20 Jahre nach SN 1987A Neutrinos from the Next Galactic Supernova

  28. Local Group of Galaxies Events in a detector with 30 x Super-K fiducial volume, e.g. Hyper-Kamiokande 30 60 250

  29. Core-Collapse SN Rate in the Milky Way Core-collapse SNe per century 7 8 0 1 2 3 4 5 6 9 10 SN statistics in external galaxies van den Bergh & McClure (1994) Cappellaro & Turatto (2000) Gamma rays from 26Al (Milky Way) Diehl et al. (2006) Historical galactic SNe (all types) Strom (1994) Tammann et al. (1994) No galactic neutrino burst 90 % CL (25 y obserservation) Alekseev et al. (1993) References: van den Bergh & McClure, ApJ 425 (1994) 205. Cappellaro & Turatto, astro-ph/0012455. Diehl et al., Nature 439 (2006) 45. Strom, Astron. Astrophys. 288 (1994) L1. Tammann et al., ApJ 92 (1994) 487. Alekeseev et al., JETP 77 (1993) 339 and my update.

  30. Nearby Galaxies with Many Observed Supernovae M83 (NGC 5236, Southern Pinwheel) D = 4.5 Mpc NGC 6946 D = (5.5 ± 1) Mpc Observed Supernovae: 1923A,1945B,1950B,1957D,1968L, 1983N Observed Supernovae: 1917A,1939C,1948B,1968D,1969P, 1980K,2002hh,2004et,2008S

  31. Large Detectors for Supernova Neutrinos LVD (400) Borexino (100) Baksan (100) Super-Kamiokande (104) KamLAND (400) MiniBooNE (200) In brackets events for a “fiducial SN” at distance 10 kpc IceCube (106)

  32. SuperNova Early Warning System (SNEWS) Neutrino observation can alert astronomers several hours in advance to a supernova. To avoid false alarms, require alarm from at least two experiments. Super-K IceCube Coincidence Server @ BNL Alert LVD Supernova 1987A Early Light Curve Others ? http://snews.bnl.gov astro-ph/0406214

  33. Simulated Supernova Signal at Super-Kamiokande Accretion Phase Kelvin-Helmholtz Cooling Phase Simulation for Super-Kamiokande SN signal at 10 kpc, based on a numerical Livermore model [Totani, Sato, Dalhed & Wilson, ApJ 496 (1998) 216]

  34. Supernova Pointing with Neutrinos 95% CL half-cone opening angle Neutron tagging efficiency None 90 % SK 7.8º 3.2º SK  30 1.4º 0.6º • Beacom & Vogel: Can a supernova be located by its neutrinos? • [astro-ph/9811350] • Tomàs, Semikoz, Raffelt, Kachelriess & Dighe: Supernova pointing with • low- and high-energy neutrino detectors [hep-ph/0307050]

  35. IceCube as a Supernova Neutrino Detector Each optical module (OM) picks up Cherenkov light from its neighborhood. SN appears as “correlated noise”. • About 300 • Cherenkov • photons • per OM • from a SN • at 10 kpc • Noise • per OM • < 500 Hz • Total of • 4800 OMs • in IceCube IceCube SN signal at 10 kpc, based on a numerical Livermore model [Dighe, Keil & Raffelt, hep-ph/0303210] Method first discussed by Halzen, Jacobsen & Zas astro-ph/9512080

  36. LAGUNA - Approved FP7 Design Study Large Apparati for Grand Unification and Neutrino Astrophysics (see also arXiv:0705.0116)

  37. Supernova Neutrinos 20 Jahre nach SN 1987A Neutrinos From All Cosmic Supernovae

  38. Diffuse Background Flux of SN Neutrinos 1 SNu = 1 SN / 1010 Lsun,B / 100 years Lsun,B= 0.54 Lsun= 2  1033erg/s En ~ 3  1053 erg per core-collapse SN 1 SNu ~ 4 Ln / Lg,B Average neutrino luminosity of galaxies ~ photon luminosity • Photons come fromnuclear energy • Neutrinos from gravitational energy For galaxies, average nuclear & gravitational energy release comparable Present-day SN rate of ~ 1 SNu, extrapolated to the entire universe, corresponds to ne flux of ~ 1 cm-2 s-1 Realistic flux is dominated by much larger early star-formation rate  Upper limit ~ 54 cm-2 s-1 [Kaplinghat et al., astro-ph/9912391]  “Realistic estimate” ~ 10 cm-2 s-1 [Hartmann & Woosley, Astropart. Phys. 7 (1997) 137] Measurement would tell us about early history of star formation

  39. Experimental Limits on Relic Supernova Neutrinos Super-K upper limit 29 cm-2 s-1 for Kaplinghat et al. spectrum [hep-ex/0209028] Upper-limit flux of Kaplinghat et al., astro-ph/9912391 Integrated 54 cm-2 s-1 Cline, astro-ph/0103138

  40. DSNB Measurement with Neutron Tagging Future large-scale scintillator detectors (e.g. LENA with 50 kt) • Inverse beta decay reaction tagged • Location with smaller reactor flux • (e.g. Pyhäsalmi in Finland) could • allow for lower threshold Pushing the boundaries of neutrino astronomy to cosmological distances Beacom & Vagins, hep-ph/0309300 [Phys. Rev. Lett., 93:171101, 2004]

  41. Supernova Neutrinos 20 Jahre nach SN 1987A Oscillations of Supernova Neutrinos

  42. Structure of Supernova Neutrino Signal 1.Collapse (infall phase) 2. Shock break out 3.Matter accretion 4. Kelvin-Helmholtz cooling Traps neutrinos and lepton number of outer core layers

  43. Neutronization Burst as a Standard Candle Different Mass Neutrino Transport Nuclear EoS If mixing scenario is known, perhaps best method to determine SN distance, especially if obscured (better than 5-10%) Kachelriess, Tomàs, Buras, Janka, Marek & Rampp, astro-ph /0412082

  44. Flavor-Dependent Fluxes and Spectra Prompt ne deleptonization burst • Broad characteristics • Duration a few seconds • En ~ 10-20 MeV • En increases with time • Hierarchy of energies • Approximate equipartition • of energy between flavors nx _ • However, in traditional • simulations transport • of nm and nt schematic • Incomplete microphysics • Crude numerics to couple • neutrino transport with • hydro code ne ne Livermore numerical model ApJ 496 (1998) 216

  45. Flavor-Dependent Neutrino Fluxes vs. Equation of State Wolff & Hillebrandt nuclear EoS (stiff) Lattimer & Swesty nuclear EoS (soft) Kitaura, Janka & Hillebrandt, “Explosions of O-Ne-Mg cores, the Crab supernova, and subluminous Type II-P supernovae”, astro-ph/0512065

  46. Level-Crossing Diagram in a SN Envelope Normal mass hierarchy Inverted mass hierarchy Dighe & Smirnov, Identifying the neutrino mass spectrum from a supernova neutrino burst, astro-ph/9907423

  47. Spectra Emerging from Supernovae Primary fluxes for for for After leaving the supernova envelope, the fluxes are partially swapped Case Mass ordering sin2(2Q13) Survival probability A Normal ≳10-3 0 cos2(Q12)0.7 B Inverted sin2(Q12)0.3 0 C Any ≲10-5 sin2(Q12)0.3 cos2(Q12)0.7

  48. Oscillation of Supernova Anti-Neutrinos Assumed flux parameters Flux ratio Mixing parameters No oscillations Oscillations in SN envelope Earth effects included Measured spectrum at a detector like Super-Kamiokande P(Dighe, Kachelriess, Keil, Raffelt, Semikoz, Tomàs), hep-ph/0303210, hep-ph/0304150, hep-ph/0307050, hep-ph/0311172

  49. Model-Independent Strategies for Observing Earth Effects One detector observes SN shadowed by Earth • Case 1: • Another detector • observes SN directly • Identify Earth effects • by comparing signals Case2: Identify “wiggles” in signal of single detector Problem: Smearing by limited energy resolution If 13-mixing angle is known to be “large”, e.g.fromDoubleChooz, observed “wiggles” in energy spectrum signify normal mass hierarchy Scintillator detector ~ 2000 events may be enough Water Cherenkov Need megaton detector with ~ 105 events Dighe, Keil & Raffelt, “Identifying Earth matter effects on supernova neutrinos at a single detector” [hep-ph/0304150]

  50. Supernova Shock Propagation and Neutrino Oscillations Schirato & Fuller: Connection between supernova shocks, flavor transformation, and the neutrino signal [astro-ph/0205390] Resonance density for R. Tomàs, M. Kachelriess, G. Raffelt, A. Dighe, H.-T. Janka & L. Scheck: Neutrino signatures of supernova forward and reverse shock propagation[astro-ph/0407132]

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