Post on 19-Dec-2015
Gamma-Ray Burst Gamma-Ray Burst Optical Observations Optical Observations
with AST3with AST3 Xue-Feng WuXue-Feng Wu
Chinese Center for Antarctic Astronomy,Chinese Center for Antarctic Astronomy, Purple Mountain Observatory, Purple Mountain Observatory, Chinese Academy of SciencesChinese Academy of Sciences
2015, March 9, Hong Kong2015, March 9, Hong Kong
2015 International Collaboration Meeting on Antarctic Survey Telescopes
Why GRB optical observations so Why GRB optical observations so important?important?
Bloom et al., 2001, ApJ, 554, 678
Metzger et al., 1997, Nature, 387, 878
GRB 970508z=0.835(t~2.3day)
host galaxy emission linesabsorption lines in afterglow spectrum
(t~6-11months)
First of all, redshift! -> distance -> luminosity/energy
Importance of GRB optical Importance of GRB optical observationsobservations
(not complete)(not complete)1.1. constraining the initial physical constraining the initial physical
parameters of GRB fireballs parameters of GRB fireballs – AST3!– AST3!2.2. diagnosing the circum-burst diagnosing the circum-burst
environments environments – AST3!– AST3!3.3. exploring the structure of GRB jets exploring the structure of GRB jets – –
AST3!AST3!4.4. (long) GRB – supernova associations (long) GRB – supernova associations ––
AST3?AST3?5.5. obtaining the host galaxy properties obtaining the host galaxy properties
(morphology, star-forming, metallicity, (morphology, star-forming, metallicity, etc.) etc.)
6.6. probing the high-redshift Universe (Pop probing the high-redshift Universe (Pop III stars, re-ionization history) with high-III stars, re-ionization history) with high-z GRBs - KDUSTz GRBs - KDUST
7.7. correlations, standard candles, correlations, standard candles, cosmography? cosmography? – AST3!– AST3!
Constraining the initial physical parameters Constraining the initial physical parameters of GRB fireballsof GRB fireballs
GRB central engine
shocked ejecta- reverse shock
shocked ISM-forward shock
Akerlof et al., 1999, Nature, 398, 400
reverse shock
forward shock
Peak of reverse shock emission:-> initial Lorentz factor (usually 100-1000)-> ISM density (typically 0.001 – 10 /cm^3)
Constraining the initial physical parameters Constraining the initial physical parameters of GRB fireballsof GRB fireballs
GRB central engine
shocked ejecta- reverse shock
shocked ISM-forward shock
Courtesy: David Coward, Zadko telescope
Peak of forward shock emission:(Liang et al. 2010, for a large sample)-> initial Lorentz factor (usually 100-1000)-> ISM density (typically 0.001 – 10 /cm^3)
forward shock
reverse shocktoo weakmagnetized ejecta?
GRB 140311A
ddiagnosing the circum-burst environmentsiagnosing the circum-burst environments
GRB central engine
ISM
log n
log R log t
log flux
shallower
wind
log R
log flux
log t
log n
n R^-2
steeper
forward shock
ddiagnosing the circum-burst environmentsiagnosing the circum-burst environments
GRB central engine
reverse shock forward shock
Light curve comparisonISM: more sharpWind: more shallow
ddiagnosing the circum-burst environmentsiagnosing the circum-burst environments
free wind -> shocked regions -> ISM
small wiggles/rebrightening in the light curveobservational requirement: continuous and dense -> AST3, Yes!
wind bubble of a Wolf-Rayet star
Geng, Wu, Li, Huang & Dai, 2014, ApJ
n(R)
Afterglow light curves (theory)
exploring the structure of GRB jetsexploring the structure of GRB jets
jet break time -> jet angle -> true energy of GRB!
jet signature
Harrison et al (1999)
two scenarios for jet breaks
Woosley, Nature, 414, 853 (2001)
Piran, Science, 295, 986 (2002)
1jet
exploring the structure of GRB jetsexploring the structure of GRB jets
Huang, Wu, Dai, Ma & Lu, 2004, ApJ
GRB 080319B
Racusin, Karpov, Sokolowski, Granot, Wu, et al., 2008, Nature
two-component jet model
1st jet
2nd jet
jet Ep
E,jet
Briggs et al et al. 1999; Ghirlanda et al. 2004; Dai et al. 2004Ghirlanda-Relation
correlations, standard candles, correlations, standard candles, cosmography?cosmography?
Using Ghirlanda-Relation
Dai et al. 2004
correlations, standard candles, correlations, standard candles, cosmography?cosmography?
tjet Ep
Eiso
Briggs et al et al. 1999; Liang & Zhang 2005
Liang-Zhang Relation
correlations, standard candles, correlations, standard candles, cosmography?cosmography?
14
Using Liang-Zhang Relation
Wei, Wu, & Melia 2013, ApJ
correlations, standard candles, correlations, standard candles, cosmography?cosmography?
GRB research with AST3
1.Regular GRB optical observation
2.GRB orphan afterglow survey
3.Merger-nova optical observation
regular regular GRB optical observationGRB optical observationII Prompt phase and early afterglowPrompt phase and early afterglow optical counterparts of prompt GRBsoptical counterparts of prompt GRBs early optical afterglowsearly optical afterglows
IIII Late optical observationLate optical observation light curve jet breakslight curve jet breaks origin of chromatic afterglowsorigin of chromatic afterglows
IIIIII GRB-SN associationsGRB-SN associations progenitors and explosion mechanismsprogenitors and explosion mechanisms
prompt/quick response (minutes to hours)
deep limit magnitude
Long GRB optical afterglow lightcurves
Kann, et al., 2010, ApJ, 720, 1513
MW dust extinction corrected
AST3 limit magnitude
Peak Mag vs. Peak Time
orphan afterglow survey
orphan afterglow
prompt GRB
afterglow
I 、 off-axis GRBs : jet, radiation is relativistic beamed
off-axis :
on-axis :
II 、 failed GRBs : less energetic (lower Lorentz factor), less gamma-ray released, even undetectable
on-axis :
orphan afterglow
jet decelerates
beaming effect decreases
true GRB rate !true GRB energy !
Metzger & Berger, 2012
SGRBMulti-band transient~hours, days, weeks, or even years
Li-Paczyński Nova
Opical flare~ 1 day
Ejecta-ISM shock
Radio~years
Li & Paczyński, 1998
Nakar& Piran, 2011
Merger-nova optical observation: EM signals for a BH post-merger (NS-NS) product
dimmer X-ray counterpart
Jet-ISM shock (Afterglow)
Shocked ISM
Ejecta
SGRB
RadioOpticalX-ray
X-ray
X-ray
Poynting flux
MNS
SGRBLate central engine activity~Plateau & X-ray flare
Magnetic DissipationX-ray Afterglow
1000 ~10000 s
8 1 210 ergs cm
Ejecta-ISM shock with Energy Injection (EI)
Multi-band transient~hours, days, weeks, or even years
Gao, Ding, Wu, Zhang & Dai, 2013Wu et al. 2014; Wang & Dai, 2013
Zhang, 2013
Merger-nova optical observation: EM signals for a ms magnetar post-merger (NS-NS) product
Photosphere emissionOptical and soft X-ray transient~ days, weeksYu, Gao &Zhang, 2013
GRB research with infrared CCD
Dust Extinction
Origin of dark GRBsDust extinction ?High-redshift GRBs?Intrinsically dark?
high-z or high extinction?
photometric z~9.4 , the most distant stellar object ever detected ?
Thank You!Thank You!