1. Afterglow Plateau and Energy Injection from Magnetar:
A Clue to Cosmological Standard Candles
M. Xu and Y. F. Huang
Department of Astronomy, Nanjing University, China
The Prompt Activity of Gamma-Ray Bursts: their Progenitors, Engines, and Radiation Mechanisms
Raleigh, NC

2. Outline Afterglow Plateau Energy Injection (EI) from Magnetar
LT correlation
LTE correlation
Cosmological Standard Candles

3. Canonical X-ray afterglow light curve
Zhang et al. 2006; Nousek et al. 2006

4. Energy Injection from Magnetar
Fireball
Energy
Injection
Kaspi et al. 2006

5. Afterglow and EI EI
Xu et al. 2008, 2009

6. Phenomenological model
Willingale et al. 2007

7. LX*∝Ta*-1.06
LT correlation
Ta*=Ta/(1+z)
Dainotti et al. 2010

8. EI from Magnetar ∝ -1 LX*∝Ta*-1.06 Assumptions： ∝ ~ ~ constant
Same parameters for new born magnetars ---Cosmological standard candles ∝ -1

9. Energy Injection from Magnetar
e+e-
Fireball EI
Dai 2004

10. Relativistic wind bubble
Dai 2004

11. Einjection < EFireball
Yu & Dai, 2007

12. LX*-T*-Eγ,iso correlation
Dai 2004
EFireball ~ Einjection~ LW T
LX* is related to fireball’s energy
LX*-T*-Eγ,iso correlation

13. LTE correlation
LX*∝Ta*-0.82Eγ,iso0.78
Xu & Huang 2011

14. LT vs LTE LTE correlation is much more tight than LT correlation.
LT: Log[L/1047erg/s]=0.77[±0.14] [±0.16] Log[T/103s]
r=-0.73, P=5.6×10-8
σint=0.85±0.097
LTE correlation is much more tight than LT correlation.
LTE: Log[L/1047erg/s]=0.73[±0.07] [±0.08] Log[T/103s] [±0.06] Log[Eiso/1053erg]
r=0.92, P=1.84×10-20
σint=0.38±0.05

15. Intermediate class GRBs
LT correlation
LTE correlation
Long IC
Dainotti et al. 2010
Xu & Huang 2011

16. Constrain the Cosmological parameters
Xu & Huang 2011

17. Summary
Afterglow plateau might be resulted from EI from Magnetar
LTE-correlation is much more tight than LT- correlation
Candidates of Cosmological Standard Candles
Thank you!