![TRACING THE SOLUTION SURFACE WITH FOLDS OF A …faculty.stust.edu.tw/~slchang/paper/paper20040616.pdf · TRACING THE SOLUTION SURFACE WITH FOLDS OF A ... 2000]. Perhaps AUTO ... Here](https://static.fdocument.org/doc/165x107/5aa145fc7f8b9a1f6d8ba003/tracing-the-solution-surface-with-folds-of-a-slchangpaperpaper20040616pdftracing.jpg)
ν-driven wind in the Aftermath of Neutron Star Merger€¦ · nν (neutrino density) calculated...
20
ν -driven wind in the Aftermath of Neutron Star Merger Albino Perego in collaboration with A. Arcones, R. Cabezon, R. K ¨ appeli, M. Liebend ¨ orfer, S. Rosswog [email protected] Technische Universit ¨ at Darmstadt Institute for Nuclear Physics, Theory GRBs in Kyoto Conference, Kyoto, 11-15 November 2013 ν -driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 1/15
Transcript of ν-driven wind in the Aftermath of Neutron Star Merger€¦ · nν (neutrino density) calculated...
ν-driven wind in the Aftermath ofNeutron Star Merger
Albino Peregoin collaboration with A. Arcones, R. Cabezon, R. Kappeli, M. Liebendorfer, S. Rosswog
Technische Universitat Darmstadt
Institute for Nuclear Physics, Theory
GRBs in Kyoto Conference, Kyoto, 11-15 November 2013ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 1/15
Outline of the presentation
Introduction: ejected matter from binary neutron starmerger
The modelinitial conditionsASL neutrino treatment
Preliminary results
Conclusion and outlook
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 2/15
Matter ejecta from BNS mergers
BNS mergers are among the most promising candidates toexplain short gamma-ray bursts (GRBs).
observations: good compatibility with observed rates,redshifts and host galaxies
modelling: intense energy deposition in a relativelybaryon-free region as driving mechanism, due to matteraccretion on a stellar compact object (SMNS or BH)
Possible ejecta from BNS mergers
dynamical ejecta (e.g. Rosswog 13, Bauswein et al 13, Hotokezaka et al 13)
delayed disc evaporation (e.g. Fernandez & Metzger 2013)
neutrino-driven ejecta (e.g. Dessart et al. 2009)
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 3/15
The model
Goal: extensive study the aftermath of BNSM
ν emission
disk dynamics and ν-driven wind formation
nucleosynthesis in the wind
baryonic pollution and GRB engine
Model ingredients:
data from Newtonian SPH BNS merger simulations(Price & Rosswog (2006))
FISH 3D (M)HD Cartesian code (Käppeli et al. (2011))
TM1 nuclear EoS (Hempel et al. (2012))
ν treatment: Advanced Spectral Leakage (ASL) scheme(Perego et al., in preparation)
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 4/15
Initial conditions
3D SPH data mapped on 3D FISH grid
1 km resolution: SMNS treated as stationary object
data relaxation: ∆t ≈ 10ms, hydro + ν emission
Matter density (2D avg) Temperature (2D avg) Electron fraction (2D avg)
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 5/15
Relevant timescales
disc lifetime:
tvisc ∼ α−1
(
H
R
)−2
Ω−
K1 ∼ 0.31 s( α
0.05
)−1(
H/R
1/3
)−2 ( R
100 km
)3/2 ( M
2.5M⊙
)−1/2
α: viscosity coefficientH: disc typical heightR: radial position in the discΩK : Keplerian angular velocity
M : SMNS mass
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 6/15
Relevant timescales
disc lifetime: tvisc ∼ 0.31 s(
α0.05
)−1(
H/R1/3
)−2 (R
100 km
)3/2 (M
2.5M⊙
)−1/2
disc dynamical time:
tdyn disc ∼2π
ΩK∼∼ 0.0109 s
(
R
100 km
)3/2 ( M
2.5M⊙
)−1/2
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 6/15
Relevant timescales
disc lifetime: tvisc ∼ 0.31 s(
α0.05
)−1(
H/R1/3
)−2 (R
100 km
)3/2 (M
2.5M⊙
)−1/2
disc dynamical time: tdyn disc ∼ 0.0109 s(
R100 km
)3/2 (M
2.5M⊙
)−1/2
disc cooling time:
tcool ∼∆Edisc,t=0∑
ν Lν∼ 0.20 s
(
∆Edisc,t=0
2× 1052erg
)(∑
ν Lν
1053erg/s
)−1
∆Edisc,t=0 = Eint,disc,t=0 + 12Egrav,disc,t=0
Lν : neutrino luminosity
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 6/15
Relevant timescales
disc lifetime: tvisc ∼ 0.31 s(
α0.05
)−1(
H/R1/3
)−2 (R
100 km
)3/2 (M
2.5M⊙
)−1/2
disc dynamical time: tdyn disc ∼ 0.0109 s(
R100 km
)3/2 (M
2.5M⊙
)−1/2
disc cooling time: tcool ∼ 0.20 s(
∆Edisc,t=0
2×1052erg
)( ∑ν Lν
1053erg/s
)−1
wind time:
twind ∼egrav
eheat∼ 0.10 s
(
M
2.5M⊙
)(
R
80 km
)(
Eν
13MeV
)−2(
(Lν)iso,θ≈π/4
4× 1052 erg/s
)−1
egrav = GM /R : specific gravitational energyeheat = Eν χabs nν / ρ : heating specific energy rate(Lν)iso : isotropized neutrino luminosityχabs : neutrino absorptivity
nν : neutrino density
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 6/15
Relevant timescales
disc lifetime: tvisc ∼ 0.31 s(
α0.05
)−1(
H/R1/3
)−2 (R
100 km
)3/2 (M
2.5M⊙
)−1/2
disc dynamical time: tdyn disc ∼ 0.0109 s(
R100 km
)3/2 (M
2.5M⊙
)−1/2
disc cooling time: tcool ∼ 0.20 s(
∆Edisc,t=0
2×1052erg
)( ∑ν Lν
1053erg/s
)−1
wind time: twind ∼ 0.10 s(
M2.5M⊙
)(
R80 km
)(
Eν13MeV
)−2(
(Lν)iso,θ≈π/4
4×1052 erg/s
)−1
tdyn disc < twind < tcool,disc < tvisc
but there is something missing . . .
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 6/15
Relevant timescales
disc lifetime: tvisc ∼ 0.31 s(
α0.05
)−1(
H/R1/3
)−2 (R
100 km
)3/2 (M
2.5M⊙
)−1/2
disc dynamical time: tdyn disc ∼ 0.0109 s(
R100 km
)3/2 (M
2.5M⊙
)−1/2
disc cooling time: tcool ∼ 0.20 s(
∆Edisc,t=0
2×1052erg
)( ∑ν Lν
1053erg/s
)−1
wind time: twind ∼ 0.10 s(
M2.5M⊙
)(
R80 km
)(
Eν13MeV
)−2(
(Lν)iso,θ≈π/4
4×1052 erg/s
)−1
tdyn disc < twind < tcool,disc < tvisc
but there is something missing . . .
SMNS → BH time (e.g. Bauswein’s and Metzger’s talk) :
tBH ∼ 0.01− 10 s
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 6/15
The ASL scheme
based on previous grey leakage schemes(Ruffert et al. 1997, Rosswog & Liebendörfer 2003, Aloy’s talk)
spectral scheme (12 bins, 2− 200 MeV)
3 flavors: νe,νe, νµ,τ (νµ,τ ≡ νµ, ντ , νµ, ντ )
ν reactions: (ν ≡ νe, νµ, ντ , νe, νµ, ντ )
e− + p → n+ νe O,T,P
e+ + n → p+ νe O,T,P
e− + (A,Z) → νe + (A,Z − 1) T,P
N + ν → N + ν O
(A,Z) + ν → (A,Z) + ν O
e+ + e− → ν + ν T,P
N +N → N +N + ν + ν T,P
major roles: O → opacity, T → thermalization, P → production
Bruenn 1985, Mezzacappa & Bruenn 1993, Hannestad & Raffelt 1998
treatment developed and tested in Core CollapseSupernova context
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 7/15
Neutrino treatment
effective scheme: ASL mimics known solutions
cooling part:smooth interpolation between diffusion andproduction (spectral) ratesreproduction of the correct limits: diffusive (τν ≫ 1)and free streaming (τν . 1)(τν neutrino optical depth)
heating part (for τν . 1):effective treatment of diffusion process in the opaqueregionnν (neutrino density) calculated with ray-tracing fromcooling rates, emitted at neutrino surfacesrheat ∝ χab · nν (χab absorptivity)
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 8/15
Neutrino Surfaces
τν = 2/3 ⇒ ν surfaces, for Eν = 4.6, 10.6, 16.2, 24.6, 57.0MeV, at 40 ms
νe νe νµ,τ
τν,scat
τν,eff
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 9/15
Neutrino luminosities
Isotropized ν luminosityemerging from ν-surfaces
0 22.5 45 67.5 90 112.5 135 157.5 1800
10
20
30
40
50
60
70
80
90
Colatitude [deg]
Iso
tro
piz
ed
lu
min
osity [
10
51 e
rg/s
]
ν
e, 0 ms
Anti−νe, 0 ms
νµ,τ
, 0 ms
ν
e, 40 ms
Anti−νe, 40 ms
νµ,τ
, 40 ms
ν rms energyemerging from ν-surfaces
0 20 40 60 80 100 120 140 160 18010
12
14
16
18
20
22
Colatitude [deg]
Ne
utr
ino
rm
s e
ne
rgy [
Me
V]
ν
e, 0 ms
Anti−νe, 0 ms
νµ,τ
, 0 ms
ν
e, 40 ms
Anti−νe, 40 ms
νµ,τ
, 40 ms
θ angular dependence at t = 0ms and t = 40ms
luminosity hierarchy: Lνe > Lνe > Lνµ,τ
mean energy hierarchy: 〈Eνµ,τ 〉 > 〈Eνe〉 > 〈Eνe〉ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 10/15
Neutrino net rates
eν @ 35 ms(
Ye)
ν@ 35 ms vν @ 35 ms
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 11/15
Disc dynamics
Movie Ileft: matter densityright: projected velocity
Movie IIleft: electron fractionright: entropy
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 12/15
Wind properties
occurrence diagrams
large variation for Ye: 0.1 . Ye . 0.35
small variation in entropy: 15 . s [kB/bar] . 25
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 13/15
Conclusions & Outlook
FISH + ASL approximate, suitable tool to model theaftermath of BNS merger
obtained neutrino signature compatible with expectedone
relatively quick ν-driven wind development
wind properties:low entropy: 15 . s[kB/baryon] . 25
mildly low Ye: 0.1 . Ye . 0.35
Outlook:
ejecta properties? → nucleosynthesis, macro/kilo-nova
ν − ν annihilation rate and baryonic pollution? → SGRBmechanism
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 14/15
ν-driven wind in the aftermath of NS merger, GRBs in Kyoto Conference - 11-15 November 2013 – p. 15/15
