ガンマ線バースト中心エンジンに関する理論的・数値的研究

2011年12月28日
長滝 重博
基研「超新星爆発とShigehiro Nagataki 数値シミュレーション」

§ Introduction	

Gamma-Ray Bursts (GRBs): the Most Powerful
Explosion 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 CGRO	

Time (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 Mechanism is still under debate.?	

Black Hole with Neutrino Heating	

MacFadyen and Woosley 99
Newtonian, Neutrinoなし。	

S.N.+07
Newtonian, Neutrinoあり。

But, Harikae+12, also Sekiguchi+12,… 	

Black Hole with Strong B-Fields	

S.N. 09
2D-GRMHD, a=0.9
Without Microphysics.
Γ< a few.	

Barkov and Komissarov 08
2D-GRMHD, a=0.9
With Some Microphysics
See also Harikae+09.	
Γ< a few.	

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

〜3000km	Black Hole Formation	

Full 2D-GRHD with Microphysics	
Sekiguchi and Shibata 11	

Full 3D-GRHD without Microphysics	
Ott+11	

Magnetar Scenario	

Komissarov and Barkov 07
2D-GRMHD with some Microphysics〜0.5. 	 See also Takiwaki+09	

Bucciantini+09
2D-SRMHD without Microphysics
Lorentz factor = 5-10	

§ Numerical Simulation of a GRB engine by a General
Relativistic Magneto-Hydrodynamic (GRMHD) code.
2D/3D GRMHD Codes written by MPI.
2D/3DSRMHD with AMR written by MPI.
（仮）YukAwa institute’s MAgneTO-hydro (YAMATO) code
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.

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

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!) is obtained only for a slowly
rotating BH. There is no constraint
For GRMHD simulations.
This solution can be used to check the validity of numerical codes.

Higher Order Terms of BZ mono-pole Solution
Numerical results for theconserved Poyinting Flux.

Red:Numerical
Blue:Analytical 	（２nd order）	
Green:Analytical(4th order)

Analytical (for a<<1) :c.f. Blandford and Znajek (1977)
Ruben (2004)

Tanabe and S.N. (2008) PRD.
T=200, c=G=M=1

Red:Numerical
Blue:Analytical 	（２nd order）	
Green:Analytical(4th order)

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<200

R<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 Kerrparameters.

Stagnation Region	
S.N. (2010)	

Kerr Parameter, a=0.95
T=160000 (=1.5760 sec).
Stagnation Region can be seen
At R=15 (=45km) in the Jet.

Density Contours in logarithmic scale (g/cc) with Velocity Fields

Blandford-Znajek Flux and Jet Energy	
S.N. 2011	
Faster is Better	

BZ (outgoing poynting)-FluxJet Energy at t=1.5750 sec for a=0,
In unit of 10^50 erg/s/Sr at0.5, 0.9, 0.95 (Solid Curves).
T=160000 (1.5760sec).
Dotted Curves represents analytical
Kerr Parameter, a=0.95.
Solution by Tanabe
Time variability is also triggered by the BH?	 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 withAdaptive Mesh Refinement (AMR)	
S.N. 2012, in prep.	

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

§Other Topics (2011-)
	Gamma-Ray Bursts as a Treasure Box of Physics & Mysteries?	

Nucleosynthesis
Central Engine	
Figure from P. Meszaros	

PhotosphericEmission?

UHECRs?
Neutrinos?	

GRB Cosmology?	

GRB/SNRemnants?	

Explosive Nucleosynthesis
In Jet-Like SNe/GRBs.
Ono, S.N.+ 2012, in prep.
Flash code with some
Micro-physics is used
Currently. We will Extend it.
Spectral-Polarization bySubaru with Dr.Tanaka (NAOJ)	

Dr. Ono at YITP (2011-)	

GRB-Cosmology	
Photospheric Emission Model and Numerical Amati relation	
Mizuta, S.N., Aoi 2010
Mizuta, S.N.+ 2012, in prep.	
Numerical
Yonetoku-Relation	Yonetoku
Relation	
Special Relativistic Hydro
Simulation by A. Mizuta	
詳細は水田さんの講演	Monte-Carlo Simulations toExplain GRB Spectrum	
フォトスフェリックモデルの下、モンテカルロ計算でバンド関数を再現する （Ito, S.N.,+ 2012, in prep）。
右図は水田氏によるシミュレーション。	

Dr. Ito at YITP (2011-)	

UV/X-rays from Failed GRBs	
Xu,,S.N., Huang, Lee 2011 ApJ, accepted.	

シミュレーションは水田氏による。
Mizuta, S.N. Aoi 2011 ApJ.
(Mizuta-san’s Talk)	

For sub-relativistic jet (Γ〜1-10), photo-sphere can be larger than Internal ShockRadius. -> Themal radiation (UV/X-rays) is followed by an afterglow.	

First Results of Telescope Array are Open Now	Green:	

Black: 	

TA@Utah	A Challenge for the GRB UHECR-Neutrino Scenario by IceCube,
But… is that true?	

Murase and S.N. 2006	
But recently, it is pointed out that the analysis of IceCube looks to contain
A serious mistake… (Hummer +arXiv:1112.1076, Li arXiv:1112.2240,He, Liu, Wang, S.N.+ 2011, in prep.)
The upper limit by IC40+59 will be not so severe as claimed by IceCube team.	
Haoning He’s Talk	Supernova Remnant Phase	Lee, Ellison,S.N. 2012, in prep.	

Radio	

RXJ1713 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.

§Other Topics 2 (2011-)
	BZ機構の磁場形状依存性	
Maeda, S.N., Mineshige, Takahashi (2012), in prep.	
冨松高橋解＋Fishbone-Moncrief解の時間発展 (このコンビネーションによるBZ数値シミュレーションは世界初)。a=0.9, t=3000GM/c^2まで(今後更に追う)。
左図：密度、右図：BZ-Flux。

PSR B1259-63/LS 2883の3次元流体
シミュレーションとガンマ線放射	

Okazaki et al. PASJ (2011)
Takata et al. ApJ 2011, submitted. 	

長滝 重博	
共同研究者： 岡崎敦男、高田順平、内藤統也、河内明子、山口正輝、早崎公威、
Shiu-Hang Herman Lee, Stan.P. Owochi	

銀河団に於けるSZ効果	
Prokhorov, Dubois, S.N. A&A (2010)
Prokhorov, Colafrancesco, Akahori, Millon, S.N., Yoshikawa MNRAS (2011)
Prokhorov, Dubois, S.N., Akahori, Yoshikawa MNRAS (2011)	

X線のSurface Brightness	

SZ（Relativistic-Correction）で求めた
電子温度分布§ 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.
• Photospheric Model is studied using Monte-Carlo simulations tounderstand the Band Function.
• One month Conference on SNe and GRBs will be held inKyoto, 2013.
• So on.