Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic...

26
Gamma-Ray Burst Gamma-Ray Burst Optical Observations Optical Observations with AST3 with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Chinese Center for Antarctic Astronomy, Astronomy, Purple Mountain Purple Mountain Observatory, Observatory, Chinese Academy of Chinese Academy of Sciences Sciences rnational Collaboration Meeting on Antarctic Survey

Transcript of Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic...

Page 1: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 2: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 3: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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!

Page 4: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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)

Page 5: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 6: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 7: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

ddiagnosing the circum-burst environmentsiagnosing the circum-burst environments

GRB central engine

reverse shock forward shock

Light curve comparisonISM: more sharpWind: more shallow

Page 8: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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)

Page 9: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 10: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 11: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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?

Page 12: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

Using Ghirlanda-Relation

Dai et al. 2004

correlations, standard candles, correlations, standard candles, cosmography?cosmography?

Page 13: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

tjet Ep

Eiso

Briggs et al et al. 1999; Liang & Zhang 2005

Liang-Zhang Relation

correlations, standard candles, correlations, standard candles, cosmography?cosmography?

Page 14: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

14

Using Liang-Zhang Relation

Wei, Wu, & Melia 2013, ApJ

correlations, standard candles, correlations, standard candles, cosmography?cosmography?

Page 15: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

GRB research with AST3

1.Regular GRB optical observation

2.GRB orphan afterglow survey

3.Merger-nova optical observation

Page 16: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 17: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

Long GRB optical afterglow lightcurves

Kann, et al., 2010, ApJ, 720, 1513

MW dust extinction corrected

AST3 limit magnitude

Page 18: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

Peak Mag vs. Peak Time

Page 19: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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 !

Page 20: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 21: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

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

Page 22: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

GRB research with infrared CCD

Page 23: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

Dust Extinction

Page 24: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

Origin of dark GRBsDust extinction ?High-redshift GRBs?Intrinsically dark?

Page 25: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

high-z or high extinction?

photometric z~9.4 , the most distant stellar object ever detected ?

Page 26: Gamma-Ray Burst Optical Observations with AST3 Xue-Feng Wu Xue-Feng Wu Chinese Center for Antarctic Astronomy, Chinese Center for Antarctic Astronomy,

Thank You!Thank You!