Afterglow Plateau and Energy Injection from Magnetar:A Clue to Cosmological Standard Candles

M. Xu and Y. F. HuangDepartment of Astronomy, Nanjing University, China

2011.03.07

The Prompt Activity of Gamma-Ray Bursts: their Progenitors, Engines, and Radiation Mechanisms

Raleigh, NC

Outline

Afterglow Plateau

Energy Injection (EI) from Magnetar

LT correlation

LTE correlation

Cosmological Standard Candles

2

Canonical X-ray afterglow light curve

3Zhang et al. 2006; Nousek et al. 2006

Energy Injection from Magnetar

4

Kaspi et al. 2006 Fireball

Energy Injection

Afterglow and EI

5

EI

Xu et al. 2008, 2009

Phenomenological model

6Willingale et al. 2007

LT correlation

7Dainotti et al. 2010

Ta*=Ta/(1+z)

LX*∝ Ta

*-1.06

EI from Magnetar

Assumptions：

∝~

~ constant~ constant

∝ -1Same parameters for new born magnetars---Cosmological standard candles

LX*∝ Ta

*-1.06

Energy Injection from Magnetar

9Fireball

EI

Dai 2004

e+e-

Relativistic wind bubble

10Dai 2004

Yu & Dai, 2007

Einjection < EFireball

Einjection ~ EFireball

12

EFireball ~ Einjection~ LW T

Dai 2004

LX* is related to fireball’s energy

LX*-T*-Eγ,iso correlation

LTE correlation

13Xu & Huang 2011

LX*∝ Ta

*-0.82Eγ,iso0.78

r=-0.73, P=5.6×10-8

LT: Log[L/1047erg/s]=0.77[±0.14] -1.16 [±0.16] Log[T/103s]

r=0.92, P=1.84×10-20

LTE: Log[L/1047erg/s]=0.73[±0.07] -0.82 [±0.08] Log[T/103s] +0.78[±0.06] Log[Eiso/1053erg]

H=69.7, ΩM=0.291

σint=0.85±0.097

σint=0.38±0.05

LT vs LTE

LTE correlation is much more tight than LT correlation.

14

Intermediate class GRBs

15

Xu & Huang 2011Dainotti et al. 2010

Long

IC

LT correlation LTE correlation

Constrain the Cosmological parameters

16Xu & Huang 2011

ΩM=0.42±0.26

Summary

Afterglow plateau might be resulted from EI from Magnetar

LTE-correlation is much more tight than LT-correlation

Candidates of Cosmological Standard Candles

17

Thank you!