ν-driven wind in the Aftermath of Neutron Star Merger

Transcription

1 ν-driven wind in the Aftermath of Neutron Star Merger Albino Perego in collaboration with A. Arcones, R. Cabezon, R. Käppeli, O. Korobkin, M. Liebendörfer, D. Martin, S. Rosswog Technische Universität Darmstadt Institute for Nuclear Physics, Theory ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 1/17

2 BNS mergers NS-NS (BH-NS) mergers intense GW emitters and major targer of GW detectors Luciano s talk candidates as central engine of short GRBs e.g. Paczynski 86, Goodman 86 nucleosynthesis from the ejecta: r-process initial n-rich matter e.g. Lattimer&Schramm74, Eichler+89,... Surman+08 dominant ν e over ν e fast expansion timescales Channels for matter ejection see also Oliver s, Yuichiro s, Brian s talks dynamical ejecta viscous ejecta ν-driven wind ejecta e.g., Korobkin+12, Bauswein+13, Hotokezaka+13, Wanajo+14 e.g., Fernandez&Metzger 13, Just+14 e.g. Dessart+09, Metzger&Fernandez 14, Perego+14, Just+14 kilo/macro- nova observation in (short) GRB130603B compatible with production of r-process elements in sgrb events e.g. Kasen+13, Grossman+14,Tanaka+14 ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 2/17

3 Physical sketch Final stages of a binary NS (2 x 1.4M ) system evolution inspiral merger hypermassive NS (HMNS) + disc Credit: Price&Rosswog 06 HMNS ( BH) 2.55M thick accreting torus 0.17M, Y e 0.05 intense ν emission L ν,tot ergs 1 ν-disc interaction: wind ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 3/17

4 Relevant time scales disc lifetime: t disc α 1 ( H R α: viscosity coefficient R disc : disc typical radius H/R: disc aspect ratio Ω K : Keplerian angular velocity M ns : HMNS mass ) 2 ( Ω 1 α ) ( ) 1 H/R 2 ( ) 3/2 ( ) 1/2 K 0.31s Rdisc Mns /3 100km 2.5M ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 4/17

5 Relevant time scales disc lifetime: t disc 0.31s ( ) ( ) α 1 H/R 2 ( ) Rdisc 3/2 ( ) 1/2 Mns /3 100km 2.5M disc L: L ν,disc E grav 2t disc ( Mns ) 3/2 ( ergs 1 Mdisc 2.5M 0.2M ( α ) ( ) R 1 ( ) ns H/R km 1/3 )( Rdisc 100km ) 3/2 E grav : gravitational energy released during accretion ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 4/17

6 Relevant time scales disc lifetime: t disc 0.31s ( ) ( ) α 1 H/R 2 ( ) Rdisc 3/2 ( ) 1/2 Mns /3 100km 2.5M ( ) 3/2 ( ) disc L: L ν,disc ergs 1 Mns Mdisc M 0.2M HMNS L: L ν,ns E ns t cool,ns ( ergs 1 E ns erg ( ρ ns ) 1 ( ) kb T 2 ns gcm 3 15MeV E ns : thermal energy t ns,cool 3τ ν,ns /(R ns c): diffusion time scale τ ν,ns : ν optical depth in HMNS )( Rns 25km ) 2 ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 4/17

7 Relevant time scales disc lifetime: t disc 0.31s ( ) ( ) α 1 H/R 2 ( ) Rdisc 3/2 ( ) 1/2 Mns /3 100km 2.5M ( ) 3/2 ( ) disc L: L ν,disc ergs 1 Mns Mdisc M 0.2M HMNS L: L ν,ns ergs 1 ( wind time: t wind e grav ė heat 0.072s ( e grav : specific gravitational energy ė heat : specific heating rate ( Mns 2.5M ξl νe ergs 1 E ns erg )( Rdisc 100km ) 1 )( Rns 25km) 2... )( Eν 15MeV ) 2 ξl νe : isotropized ν e luminosity at θ π/4, ξ 1.5 and L νe (L ns +L disc )/3 ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 4/17

8 Relevant time scales disc lifetime: t disc 0.31s ( ) ( ) α 1 H/R 2 ( ) Rdisc 3/2 ( ) 1/2 Mns /3 100km 2.5M ( ) 3/2 ( ) disc L: L ν,disc ergs 1 Mns Mdisc M 0.2M HMNS L: L ν,ns ergs 1 ( wind:t wind 0.072s E ns erg ( )( )( ) Mns Rdisc 2 ( Eν 2.5M 100km 15MeV )( Rns 25km) 2... ) ξl 1 ν e ergs 1 t wind < t disc ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 4/17

9 Relevant time scales disc lifetime: t disc 0.31s ( ) ( ) α 1 H/R 2 ( ) Rdisc 3/2 ( ) 1/2 Mns /3 100km 2.5M ( ) 3/2 ( ) disc L: L ν,disc ergs 1 Mns Mdisc M 0.2M HMNS L: L ν,ns ergs 1 ( wind:t wind 0.072s E ns erg ( )( )( ) Mns Rdisc 2 ( Eν 2.5M 100km 15MeV )( Rns 25km) 2... ) ξl 1 ν e ergs 1 t wind < t disc HMNS BH: EoS, M ns, B ns, ang. mom. transport, etc. our assumption: t bh 0.1s t bh s ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 4/17

10 Goals & model Goal: study of the aftermath of BNSM under ν influence ν emission disc dynamics and ν-driven wind formation nucleosynthesis in the wind e.m. counterparts Perego+14, to be published in MNRAS Model ingredients: HD: FISH 3D Newtonian Cartesian code Käppeli+11 EoS: TM1 nuclear EoS Hempel+12 stiff EoS, large NS radii cf Wanajo+14 ν treatment: Advanced Spectral Leakage (ASL) scheme initial conditions: final stage of M no-spin NS merger high resolution Newt. SPH simulation + multi-flavor ν cooling Rosswog&Price 06 dynamical evolution: 100 ms ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 5/17

11 Neutrino treatment: the ASL scheme effective scheme: ASL mimics known solutions 3-flavors, spectral scheme, based on previous grey leakage schemes Ruffert+97, Rosswog&Liebendörfer 03 cooling part smooth interpolation between diffusion and production (spectral) rates reproduction of the correct limits: diffusive (τ ν 1) and free streaming (τ ν 1) heating part (for τ ν 1): n ν (neutrino density) calculated by ray-tracing algorithm; input: emission rates at ν-surfaces r heat χ ab n ν (χ ab absorptivity) ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 6/17

12 Initial conditions 3D SPH data mapped on 3D FISH grid 1 km resolution: HMNS treated as stationary object data relaxation: t 10ms, hydro + ν emission density, velocity, Y e, temperature 2D slice of 3D domain, at t = 0 ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 7/17

13 Neutrino Surfaces τ ν = 2/3 ν surfaces, for E ν = 4.6,10.6,16.2,24.6,57.0MeV, at 40 ms ν e ν e ν µ,τ τ ν,scat τ ν,eff ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 8/17

14 Neutrino luminosities dependence on time 60 ν e, net anti ν e, net ν µ,τ, cooling 50 ν e, cooling ν e, HMNS anti ν e, cooling anti ν e, HMNS ν µ,τ, HMNS Neutrino luminosity [10 51 erg/s] Time [ms] HMNS (ρ > gcm 3 ) ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 9/17

15 Neutrino luminosities dependence on time 60 ν e, net anti ν e, net ν µ,τ, cooling 50 ν e, cooling ν e, HMNS anti ν e, cooling anti ν e, HMNS ν µ,τ, HMNS Neutrino luminosity [10 51 erg/s] Time [ms] HMNS (ρ > gcm 3 ) + disc ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 9/17

16 Neutrino luminosities dependence on time 60 ν e, net anti ν e, net ν µ,τ, cooling 50 ν e, cooling ν e, HMNS anti ν e, cooling anti ν e, HMNS ν µ,τ, HMNS Neutrino luminosity [10 51 erg/s] Time [ms] HMNS (ρ > gcm 3 ) + disc luminosity hierarchy: L νe > L νe > L νµ,τ disc luminosity powered by accretion: Ṁ M s 1 &α num 0.05 ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 9/17

17 Neutrino luminosities Neutrino luminosity [10 51 erg/s] dependence on time ν e, net anti ν e, net ν µ,τ, cooling ν e, cooling anti ν e, cooling ν µ,τ, HMNS ν e, HMNS anti ν e, HMNS dependence on θ (t = 40ms) Isotropized luminosity [10 51 erg/s] L 70 cool, ν e L, Anti ν cool e <E cool >, ν e <E >, Anti ν cool e Mean energy [MeV] Time [ms] HMNS (ρ > gcm 3 ) + disc luminosity hierarchy: L νe > L νe > L νµ,τ disc luminosity powered by accretion: Ṁ M s 1 &α num Colatitude [deg] mean energy hierarchy: E νµ,τ > E νe > E νe E νe 11MeV,E νe 15MeV, E νµ,τ 18MeV disc-shadow effect ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 9/17

18 Neutrino net rates ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 10/17

19 Disc and wind dynamics Picture I left: matter density right: projected velocity Picture II left: electron fraction right: entropy Click here for the video ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 11/17

20 Wind properties 2D mass-histograms of (ρ,y e ) and (ρ,s) large variation for Y e : 0.1 Y e 0.40 small variation in entropy: 10 s [k B /bar] 22 Click here for the video ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 12/17

21 Ejecta criteria: 1) e tot = e kin +e th +e pot > 0 & 2) v r > 0 & 3) θ < 60 o nuclear recombination energy included ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 13/17

22 Ejecta criteria: 1) e tot = e kin +e th +e pot > 0 & 2) v r > 0 & 3) θ < 60 o nuclear recombination energy included high latitudes (0 o < θ < 40 o ) Histograms of the ejecta at t = 91 ms (e tot >0) m ej (t = 91ms) M m ej (t = t disc ) M Y e : s: k B baryon 1 v r : c low latitudes (40 o < θ < 60 o ) m ej (t = 91ms) M m ej (t = t disc ) M Y e : s: k B baryon 1 v r : c log 10 Mass [M sol ] log 10 Mass [M sol ] 0 o < θ < 40 o x 10 3 M sol o < θ < 60 o x 10 3 M sol Y [ ] e s [k B /baryon] ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 13/17

23 nucleosynthesis: representative tracers Mass fraction, X i H1: H2: H3: H4: H5: solar (sc.) Mass number, A Mass fraction, X i L1: L2: L3: L4: L5: solar (sc.) Mass number, A post-processed with WinNet no robust r-process weak r-process (70 A 110) Winteler et al (2012) significant differences between high and low latitudes ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 14/17

24 e.m. transient: bolometric luminosity H1 H2 H3 H4 H5 L1 L2 L3 L4 L L [erg/s] L [erg/s] time [d] time [d] L γ powered by radioactive material in the wind model by Kulkarni 05 m ej M v ej 0.08c uniform grey opacity: κ h = 1cm 2 g 1 VS κ l = 10cm 2 g 1 different shapes reflect individual nuclear heating conditions Tanaka&Hotokezaka 13, Grossmann+14 ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 15/17

25 e.m. transient: broadband lightcurves U B R J H J dyn. ejecta U B R J H J dyn. ejecta AB magnitude AB magnitude time [d] top/on-axis view time [d] side/off-axis view AB broadband lightcurves high latitude: peak in B band at t 1.3d low latitude: dimmer, redder and delayed comparison with dynamical ejecta (m dyn M ) ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 16/17

26 Conclusions and outlook genuine ν-driven wind from ν heating in the disc (t wind tensms) both HMNS (cooling) and disc (accretion) L ν ν-driven wind contributes substantially ( M ) to ejecta in BNS mergers mildly neutron-rich ejecta (0.2 Y e,ejecta 0.4); high latitude wind: weak r-process nucleosynthesis (A ) stronger irradiations larger Y e,s,v ej large Y e range: no robust r-process wind e.m. transient depends on geometry and relative orientation high latitude outflow powers bluer and brighter lightcurve, that peaks 1 d low latitude outflow redder and dimmer lightcurve, that peaks few ds Outlooks ν-driven wind and GRB mechanism role of ν oscillations in wind-dynamics and nucleosynthesis role of GR on ν emission e.g. Murguia-Berthier+14 Malkus+14, Gail s talk Caballero+12 detailed nucleosynthesis and e.m. transient ν-driven wind in the aftermath of NS merger, - The r-process: status and challenges, Seattle, 29 July 2014 p. 17/17