Download Tight L iso -E p -Γ 0 Relation of Long Gamma

Tight Liso-Ep-Γ0 Relation of
Long Gamma-Ray Bursts
Enwei Liang
Guangxi University, China
IAUS 324: New Frontiers in BH Astrophys.
2016.9.12-9.16, Ljubljana Selovenia
General Picture of Gamma-Ray Bursts
GRBs and their afterglows
are produced from
extremely relativistic jets
powered by the central
engine.
V ≥ 0.9999c
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Estimating the Initial Γ0 of GRB jets
With
the fireball deceleration
time(e.g.,Sari & Piran 1999)
Liang + 2010
With
the "compactness" argument:
(e.g.,Lithwick & Sari 2001)
With
the photosphere radiation:
(e.g. Zou + 2015)
Tang + 2014
Peng + 2014
Optical and X-ray afterglow Cartoon
Lightcurves
X-ray Emission
components
Optical Emission
components
Zhang et al. 2006, ApJ; Li, Liang et al. 2012, ApJ
Relation between afterglow onset and
prompt gamma-rays
 Optical afterglow onset is
detected for 1/3 of GRBs
 Onset peak luminosity is
correlated with prompt
gamma-ray luminosity.
Liang et al. 2010, ApJ
Eiso (or Liso)-Γ0 Relation
A tight correlation between the Eiso and the
Lorentz factor of GRB fireball
Liang et al. 2010，2013, ApJ; LV et al. 2012, ApJL
Eiso (or Liso)-Ep Relation
These relations was found with
GRBs detected with BeppoSAX
and also confirmed with Swift/BAT
and Fermi/GBM GRBs.
Amati et al. 2012, IJMPD
Yonetoku et al. 2004, ApJ
Lu et al. 2012, ApJ
Eiso (or Liso)-Ep vs. Eiso (or Liso)-Γ0 Relation
Amati et al. 2012, IJMPD


Liang et al. 2010, ApJ
Is the large intrinsic dispersion of pair
correlations due to missing of the third part?
Relation among the three parameters?
A tight Liso-Ep,z-Γ0 relation
GRB 060218: Γ0 ~ 2.3
（Soderberg + 2006）
Liang + 2015, ApJ
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A tight Liso-Ep,z-Γ0 relation
Double check with
GRBs whose Γ0 are
derived from the
spectral cutoff energy
observed with
Fermi/LAT.
GRB 060218: Γ0 ~ 2.3
（Soderberg + 2006）
Liang + 2015, ApJ
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Liso-Ep,z-Γ0 as a new GRB cosmology
ruler?


Ejet-Ep relation
(Ghirlanda + 2004)
Eiso-Ep-tjet relation (Liang
& Zhang 2005)
Dai, Liang, & Xu 2004, ApJL； Liang & Zhang 2005, ApJ
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Liso-Ep,z-Γ0 as a new GRB cosmology
ruler?



Advantages:
 A tighter relation than
previous ones.
Issues:
 Needing to be confirmed
with LL-GRBs (moderate
relativistic jets?)
 Needing to geometric
correction to Liso
 Identifying the cosmic
evolution of jet luminosity.
Liang + 2015; Xin + 2016
？
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3. Our On-Going Observational Project
GRB trigger Follow-up
Flux
Hu+ 2014
GRBs
Optical Tels
Singer+2012
magnitude
R=13 Mini-GWAC
R=16 GWAC
R=19 60/80cm
-400s -200s 0 100s 5m 1h 1d
R=21
iPTF
Our Current Optical Monitoring Project
10m
trigger
30s
Identification
and early
photometry
Spectrum、
redshift
hours
Late
photometry
GWAC/GRB alert 60/80cm Telescope2m telescope
Examples of Our Monitoring Results
Mini-GWAC upper limit : M=13.2
GRB 160131A
B, V, R, I observations with our 60/ 80 cm
telescopes in Xinglong Observatory.
Liang + 2016, in prep.
GRB 140629
Xin + 2016, ApJ, submitted
Zhong + 2016, ApJ, in press
Huang + 2016, ApJ, in press
Xin + 2016a, ApJ
Summary
Thanks!
 Measuring the jet initial Lorentz factors of
GRBs with the fireball deceleration time
observed in the optical band range from ~100 to
1000.
 The Lorentz factors are correlated with Liso (or
Eiso), and a tighter correlation is found by
adding Ep.
 The Liso-Ep,z-Γ0 may be a promising GRB
cosmology ruler, but issues are still there.
 Our new observational project is going on for
pushing the cosmology use of this relation .
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