gamma-ray burst ring-shaped jets and their afterglows
DESCRIPTION
Gamma-Ray Burst Ring-shaped Jets And Their Afterglows. Ming Xu Department of Astronomy, Nanjing University 2010.06.22. Collaborators: Yongfeng Huang, Siwei Kong. Gamma-ray Sky from Fermi: Neutron Stars and their Environment—Hong Kong. Outline. GRB jets Structure of ring-shaped jets - PowerPoint PPT PresentationTRANSCRIPT
Gamma-Ray Burst Ring-shaped Jets And Their Afterglows
Ming XuDepartment of Astronomy, Nanjing
University2010.06.22
Gamma-ray Sky from Fermi: Neutron Stars and their Environment—Hong Kong
Collaborators: Yongfeng Huang, Siwei Kong
Outline
GRB jets
Structure of ring-shaped jets
Afterglows of ring-shaped jets
Early rebrightening from ring-shaped jet
Conclusions
2
Gamma-Ray Burst
3Gamma-ray bursts are short and intense unpredictable flashes of gamma-ray photons.
Light curve of GRB-complicated
Millisecond
Stellar scale
4
Center star
Peculiar properties of GRB
High redshift GRB 090423 z=8.2
Nearby GRB GRB 980425 z=0.0085
High luminosity GRB 080607 Liso=2.2×1054 erg/s
“Naked GRB” GRB 080319B mV=5.3
Ultra-relativistic GRB 090510 Γ>1200
High engrgy photon GRB 090902B hν=33.4 GeV
Huge isotropic energy GRB 080916C Eiso=5.6×1054 ergs
5
M⊙c2=1.8×1054ergs
GRBs Isotropic energy (ergs)
GRB 990123 Eiso=2.8×1054 ergs
GRB 000131 Eiso=1.8×1054 ergs
GRB 050904 Eiso=1.2×1054 ergs
GRB 080319B Eiso=1.3×1054 ergs
GRB 080607 Eiso=1.9×1054 ergs
GRB 080916C Eiso=5.6×1054 ergs
GRB 090323 Eiso=4.1×1054 ergs
GRB 090510 Eiso=1.1×1054 ergs
Amati 08,09,10; Ghirlanda 08,09,10
Eiso VS M ⊙ c2
6
Stellar scale
1. GRB Jets
7
GRB Jet Beaming Angle
Gao & Dai 2010
<θ> ~ 3.4°
f-1~ 1100
8
Intrinsic energy
GRB Jet Models
Uniform jet (UJ)
Universal structured jet (USJ)
Cylindrical jet (CJ)
Gaussian jet (GJ)
Two-component jet (TCJ)
“Fan” shaped jet (FSJ)
“Ring” shaped jet (RSJ)9
θ jet
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Ring” shaped jet
“Fan” shaped jet10
jet
Most familiar
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Ring” shaped jet
“Fan” shaped jet11
Not uniform
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Ring” shaped jet
“Fan” shaped jet12
jet
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Ring” shaped jet
“Fan” shaped jet13
jet
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Ring” shaped jet
“Fan” shaped jet14
jetnarrow
wide
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Fan” shaped jet
“Ring” shaped jet15
jet
GRB Jet Models
Uniform jet
Universal structured jet
Cylindrical jet
Gaussian jet
Two-component jet
“Fan” shaped jet
“Ring” shaped jet16
ring
hollow
Granot 2005
GRB Jet Models
17
2. GRB ring-shaped Jets
If GRB jet axis is precessing around the spin axis, there may be produced a ring-shaped jet.
Fargion et al. 200618
Aloy & Rezzolla 2006 Mizuno et al. 2008
Quasi ring-shaped Jet
19
Sketch of ring-shaped jet
Xu et al. 2008a20
Evolution of a ring-shaped jet
Xu et al. 2008a21
Inner edge
Outer edge
RSJ
Evolution of a ring-shaped jet
Xu et al. 2008a22
Inner edge
Outer edge
UJ
Evolution of a ring-shaped jet
23
ISM
Afterglows
ring
3. Afterglow light curves of ring-shaped jet
Xu et al. 2008a24
ring
UJ
Line of sight on ring
Effect of parameters on LC (1)
Xu et al. 2008a 25
magnetic energy fractionelectronic energy fraction
opening angle of the central coneobserving angle
Effect of parameters on LC (2)
Xu et al. 2008a26
Number density of ISM power-low index of electron energy distribution
Afterglows LC of ring-shaped jet
Xu et al. 2008a
X-ray band Radio (8.5Ghz) band
27
R-band
Fit to afterglow of GRB 050820A
Xu et al. 2008b28
4. Rebrightening from ring-shaped jet
Xu et al. 2008a
On the ring
In hollow cone
29
Rebrightening VS Flare
Chincarini et al. 2007Margutti et al. 2010
>1
30
GRB 081028
t
Δt
Rebrightening from off-axis model
Margutti et al. 2010
31
GRB 081028
Line of sight
Prompt emission?
Early rebrightening of GRB 070208
http://www.swift.ac.uk/xrt_curves/00259714/ 32
Compare to off-axis conical jet
Line of sight
The ring-shaped jet model is superior over the normal off-axis conical jet model when considering the production of the intensive γ-ray radiation in the prompt GRB phase.
33
Xu & Huang 2010
Early rebrightenings from ring-shaped jets
34
Line of sight in the central axis of hollow cone
Afterglow LC similar to conical jet
Effect of parameters on LC
Early rebrightenings of GRB afterglow may be resulted from ring-shaped jets
Conclusions
35
Thank you!