ガンマ線バースト・極超新星に於ける爆発的元素合成
Explosive Nucleosynthesis in Gamma-Ray Bursts and Hypernovae

長滝 重博
Shigehiro Nagataki

2011年12月4日
伊勢志摩§ Introduction

Gamma-Ray Bursts (GRBs): the Most PowerfulExplosion in the Universe
Some GRBs are found to be associated with peculiar supernovae (hypernovae)
whose explosion energy is 10 times greater than normal core-collapse
supernovae. Only small fraction of supernovae can have GRBs.

Counts/s
A GRB by CGROTime (sec)Movie of a Long GRB (Imagination)
From NASA’s HP.

Short History of the Central
Engine of GRBs.
• First report on the association of a GRB witha hypernova was done in 1998.
• Black Hole with Neutrino Heating?
E.g. MacFadyen and Woosley 1999; S.N. + 2007
• Black Hole with Strong B-Fields?
E.g. S.N. 2009, 2011.
• Neutron Star with Strong B-Fields (Magnetar)?
E.g. Takiwaki, Kotake, S.N., Sato 2004.
BH or NS?
Neutrino or B-Field?
Outline of Explosion is still under debate.?

§ Numerical Simulation of a GRB engine by a General
Relativistic Magneto-Hydrodynamic (GRMHD) code.
2D/3D GRMHD Codes written by MPI.
SRHD with AMR written by MPI.
S.N. ApJ (2009).
S.N. PASJ (2011).
S.N. 2012, in prep.

General Relativistic Numerical Code is necessary to see generalrelativistic effects.
Energy extraction from a Black Hole (Blandford-Znajek Process) is one ofthem.
This effect may be the key process of the GRB engine.

What is Blandford-Znajek Process?
Blandford and Znajek 1977
Tanabe and S.N. PRD 2008

Energy extraction from a rotating BH: General Relativistic EffectIn principle,Rotation Energy of a BH can be
Extracted when particles with negative
Energy are absorbed into the BH.

Analytical solution (only mono-poleSolution!) was introduced by BZ.
Nowadays, this effect can be seen
Numerically with a GRMHD code.

Basic Equations

Additional Equations(ConstrainedTransport)

Flux term(HLL Method)

SolverConserved
Variables
Newton-Raphson Method
Primitive
Variables

Slope (2nd order in Space, 3rd in time)
Mimmod or Monotonized Center
TVD Runge-Kutta

Initial Condition for GRB Simulations
S. N. 09

• Rotating Massive Stellar Model by Woosleyand Heger 2006.
• Fe core is extracted and a rotating black holeis put instead.
• MBH=2Msolar, a=0.5 (Fixed Kerr Metric).
••• Minimum value ofSimulation of a Collapsar
S.N. 2009

R<200R<5000

Density contour in logarithmic scale (g/cc)
Final time corresponds to 1.77sec. R=200 corresponds to 600km.

Dependence of Dynamics on Rotating Black Hole
a=0

a=0.5

S.N. 2011

Density Structure
at T=1.6sec.

a=0.9

a=0.95

Not the Time
Sequence, but
For Different Models
With different Kerr
parameters.

Blandford-Znajek Flux and Jet Energy
S.N. 2011

Faster is Better

BZ (outgoing poynting)-Flux
In unit of 10^50 erg/s/Sr at
T=160000 (1.5760sec).
Kerr Parameter, a=0.95.
Time variability is also triggered by the BH?

Jet Energy at t=1.5750 sec for a=0,0.5, 0.9, 0.95 (Solid Curves).
Dotted Curves represents analytical
Solution by Tanabe
And S.N. (2008) and Tchekhovskoy
et al. (2010) with B=5*10^14G.

3D-GRMHD Simulation of GRBs
S.N. 2012, in prep.

～3000kmCombining SRHD Code with
Adaptive Mesh Refinement (AMR)
S.N. 2012, in prep.

Paramesh:http://www.physics.drexel.edu/~olson/paramesh-doc/Users_manual/amr.html

Explosive Nucleosynthesis
In Jet-Like Sne/GRBs.
Ono and S.N. 2011, in prep.
Flash code with some
Micro-physics is used
Currently.
We are planning to couple
My GRMHD code withMicro-physics in Flash
Such as Nuclear-Reactions
To discuss 56Ni production.

Dr. Ono at YITP (2011-)

Supernova Remnant Phase
Lee, Ellison,S.N. 2011, in prep.

RadioRXJ1713 in TeV-Gamma (color, HESS)And X-rays (contour, ASCA)Age is about 1600yrs.

X-rays

GeV-TeVGamma-rays

Shiu-Hang (Herman)
Lee at YITP (2011-)

Supernovae and Gamma-RayBursts in Kyoto, 2013
• Oct.-Nov. in 2013 (preliminary).
• 1 month workshop at YITP.

§ Summary

Summary• General Relativistic Magneto-Hydrodynamic (GRMHD) Codehas been developed from scratch.
• Fast-rotating Black Hole is better to produce an energetic GRB
jet (Faster is Better) due to Blandford-Znajek process.
• GRB simulations by 3D GRMHD code are being done.
• Adaptive Mesh Refinement has been attached to SRHD code.
• Explosive Nucleosynthesis (56Ni production) is being studied
by Flash code using nuclear reaction network.
• Supernova remnants are being studied taking account ofparticle acceleration and emission mechanisms including line
emissions from heavy nuclei in SNRs.
• One month Conference on SNe and GRBs will be held inKyoto, 2013.