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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
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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 Afterglows of ring-shaped jets Early rebrightening from ring-shaped jet Conclusions
Gamma-Ray Burst Gamma-ray bursts are short and intense unpredictable flashes of gamma-ray photons.
Light curve of GRB-complicated Millisecond Center star Stellar scale 4
Eiso VS M⊙c2 M⊙c2=1.8×1054ergs Stellar scale Amati 08,09,10; Ghirlanda 08,09,10
GRB Jet Beaming Angle <θ> ~ 3.4° Intrinsic energy f-1~ 1100 Gao & Dai 2010
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) θ jet
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Ring” shaped jet “Fan” shaped jet jet Most familiar
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Ring” shaped jet “Fan” shaped jet Not uniform
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Ring” shaped jet “Fan” shaped jet jet
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Ring” shaped jet “Fan” shaped jet jet
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Ring” shaped jet “Fan” shaped jet wide jet narrow
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Fan” shaped jet “Ring” shaped jet jet
GRB Jet Models Uniform jet Universal structured jet Cylindrical jet Gaussian jet Two-component jet “Fan” shaped jet “Ring” shaped jet ring hollow
GRB Jet Models Granot 2005
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. 2006
Quasi ring-shaped Jet Mizuno et al. 2008 Aloy & Rezzolla 2006
Sketch of ring-shaped jet Xu et al. 2008a
Evolution of a ring-shaped jet Outer edge Inner edge RSJ Xu et al. 2008a
Evolution of a ring-shaped jet Outer edge Inner edge UJ Xu et al. 2008a
Evolution of a ring-shaped jet ring ISM Afterglows
3. Afterglow light curves of ring-shaped jet Line of sight on ring UJ ring Xu et al. 2008a
Effect of parameters on LC (1) opening angle of the central cone observing angle Xu et al. 2008a electronic energy fraction magnetic energy fraction
Effect of parameters on LC (2) Number density of ISM power-low index of electron energy distribution Xu et al. 2008a
Afterglows LC of ring-shaped jet X-ray band Radio (8.5Ghz) band Xu et al. 2008a
Fit to afterglow of GRB 050820A R-band Xu et al. 2008b
4. Rebrightening from ring-shaped jet On the ring In hollow cone Xu et al. 2008a
Rebrightening VS Flare >1 GRB 081028 Δt t Margutti et al. 2010 Chincarini et al. 2007
Rebrightening from off-axis model GRB 081028 Line of sight Prompt emission? Margutti et al. 2010
Early rebrightening of GRB 070208 http://www.swift.ac.uk/xrt_curves/00259714/
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.
Early rebrightenings from ring-shaped jets Line of sight in the central axis of hollow cone Xu & Huang 2010
Conclusions Afterglow LC similar to conical jet Effect of parameters on LC Early rebrightenings of GRB afterglow may be resulted from ring-shaped jets Thank you!