Gam

ma-R

ay B

urs

ts

and

High Energy Astrophysics

Jo

nath

an

Gra

no

tJo

nath

an

Gra

no

t

Univ

ers

ity o

f H

ert

ford

shire

Univ

ers

ity o

f H

ert

ford

shire

Univ

ers

ity o

f H

ert

ford

shire

Univ

ers

ity o

f H

ert

ford

shire

(Royal S

ocie

ty W

olfson R

esearc

h M

erit A

ward

Hold

er)

(Royal S

ocie

ty W

olfson R

esearc

h M

erit A

ward

Hold

er)

ST

FC

Intr

oducto

ry S

um

mer

School fo

r new

researc

h s

tudents

in a

str

onom

y, U

niv

ers

ity o

f H

ert

ford

shire, S

epte

mber

2,

2008

Ou

tlin

e o

f th

e T

alk

:O

utl

ine o

f th

e T

alk

:•

Hig

h e

ner

gy A

stro

physi

cs:

•W

hat

is

it ?

(so

me

po

ssib

le d

efin

itio

ns)

•R

elev

ant

astr

op

hy

sica

l o

bje

cts

and

ph

ysi

cs

•G

amm

a-R

ay B

urs

ts (

GR

Bs)

:•

Ch

ron

olo

gic

al O

ver

vie

w

(dem

on

stra

tes

ho

w a

fie

ld e

vo

lves

)(d

emo

nst

rate

s h

ow

a f

ield

ev

olv

es)

•M

enti

on

th

e m

ost

im

po

rtan

t sp

ace

mis

sio

ns

•O

ver

vie

w o

f m

ain

ob

serv

atio

ns

& t

heo

ry

•L

ast

few

yea

rs:

som

e h

igh

lig

hts

fro

m Swift

•P

rosp

ects

fo

r th

e fu

ture

(po

ten

tial

are

as f

or

a P

hD

th

esis

)

What is high-energy astrophysics?

So

me p

ossib

le d

efi

nit

ion

s:

•S

tudy o

f astr

onom

ical obje

cts

know

n to

pro

duce h

igh-e

nerg

y p

hoto

ns

•In

terp

reta

tion o

f phenom

ena s

een in X

-ray

and g

am

ma-r

ay o

bserv

ations

and g

am

ma-r

ay o

bserv

ations

•S

tudy o

f astr

onom

ical obje

cts

th

at

pro

du

ce

hig

h-e

nerg

y p

art

icle

s

•O

bserv

ations a

t w

avele

ngth

s in the X

-ray

regim

e o

r above (

hig

h e

nerg

y a

str

on

om

y)

Relevant Objects or Phenomena

•C

om

pact obje

cts

: w

hite d

warf

s, neutr

on s

tars

, b

lack h

ole

s (

talk

by P

rof. C

hris D

one)

•A

ctive G

ala

ctic N

ucle

i (D

r. D

ave A

lexander)

•C

osm

ic r

ays, neutr

inos, gra

vitational w

aves

(astr

o-p

art

icle

physic

s; ta

lk b

y D

r.Jim

Hin

ton)

(astr

o-p

art

icle

physic

s; ta

lk b

y D

r.Jim

Hin

ton)

•G

ala

xy c

luste

rs (

talk

by D

r. J

udith C

rosto

n)

•S

upern

ova e

xplo

sio

ns a

nd r

em

nants

•P

uls

ars

, P

uls

ar

Win

d N

ebula

e, M

agneta

rs

•X

-ray b

inaries, m

icro

-quasars

(C

hris’s

talk

~)

•G

am

ma-r

ay B

urs

ts(G

RB

s; m

ost of th

is talk

)

Relevant Physics

•E

xtr

em

e d

ensitie

s a

nd/o

r m

agnetic fie

ld

•S

trong fie

ld g

ravity (

Ne

utr

on

Sta

rs, B

lack H

ole

s)

•P

art

icle

accele

ration

•(R

ela

tivis

tic)

Colli

sio

nle

ss s

hock p

hysic

s

(part

icle

accele

ration,

magnetic f

ield

am

plif

ication,…

)(p

art

icle

accele

ration,

magnetic f

ield

am

plif

ication,…

)

•R

ela

tivis

tic flo

ws M

HD

/RM

HD

/GR

MH

D

•R

adia

tive p

rocesses, ra

dia

tive tra

nsfe

r

•M

agnetic fie

lds, pla

sm

a p

hysic

s

•N

ucle

ar

physic

s (

Ne

utr

on

Sta

rs, S

up

ern

ova

e)

General Types of Work:

•In

str

um

en

tati

on

: help

desig

n a

nd/o

r build

in

str

um

ents

to o

bserv

e r

ele

vant obje

cts

•O

bserv

ati

on

: pla

n, perf

orm

and a

naly

ze

rele

vant observ

ations o

f th

ese o

bje

cts

•P

hen

om

en

olo

gy: In

terp

ret &

pro

vid

e a

genera

l pic

ture

ofpart

icula

r phenom

ena

genera

l pic

ture

ofpart

icula

r phenom

ena

•T

heo

ry: stu

dy o

f th

e u

nderlyin

g p

hysic

al

pro

cesses a

t w

ork

behin

d the o

bserv

ations

(often c

om

mon to d

iffe

rent obje

cts

)

•A

typic

al P

hD

involv

es 1

or

2 o

f th

e a

bove

(the b

ord

erlin

es a

re n

ot alw

ays v

ery

cle

ar)

Gamma

Gamma--Ray Busts (GRBs):

Ray Busts (GRBs): Discovery

Discovery

“V

ela” se

ries of

1960s US sat

ellites inte

nded

to m

onitor

tre

aty ban

ning

nuc

lear

tests in

spac

e

First G

RB detected in July 2,1967

This w

as dete

rmined only in 1969

Declassified and

pub

lished only in 1973

Trian

gulation

show

ed these

eve

nts

came fro

m beyo

nd the S

olar

sys

tem

Exam

ple

s o

f g

am

ma-r

ay l

igh

t cu

rves

(div

ers

e &

typ

ically h

igh

ly v

ari

ab

le)

Som

e bizar

re explan

ations

were

con

sidere

d…

In

th

e e

arl

y y

ears

: m

any t

heories,

most of w

hic

h invoked a

Gala

ctic (

typic

ally

NS

) origin

; at som

e p

oin

t N

the

ori

es

> N

GR

Bs

!!!

Har

d to mak

e pro

gress w

ithou

t kn

owing th

e dista

nce sca

le

A few peop

le liked the idea th

at G

RBs may

be

extrag

alac

tic, pos

sibly high redsh

ift (not

ably

Boh

dan

Paz

cyns

ki 19

86) .

But then the ene

rgies would be huge!

(1940 -

2007)

Compton Gamma

Compton Gamma--Ray Observatory

Ray Observatory

(1991

(1991--1999)

1999)

BATSE

: se

nsi

tiv

e al

l sk

y G

RB

det

ecto

r (30 keV

–2 M

eV)

Fou

nd an isot

ropic distribut

ion of

GRBs on

the sky

This fav

ours a cos

molog

ical origin (thou

gh som

e still

invo

ked an exte

nded G

alac

tic halo)

Bim

od

al

Dis

trib

uti

on

: L

on

g v

s.

Sh

ort

~2 s

T

his

suggeste

d tw

o d

istinct cla

sses o

f burs

ts

GR

Bs:

GR

Bs:

Ob

serv

ati

on

s

Ob

serv

ati

on

s --

Pro

mp

t G

RB

Pro

mp

t G

RB

V

ari

ab

le lig

ht

cu

rve

D

ura

tio

n:

~~1

01

0−−

22––

10

10

33se

cse

c

S

pe

ctr

um

: n

on

-th

erm

al

Tim

eT

ime

Flux

Tim

eT

ime

S

pe

ctr

um

: n

on

-th

erm

al

ννFFννp

ea

ks

at

pe

ak

s a

t ~

~

00..11

--1

1 M

eV

Me

V

R

ap

id v

ari

ab

ilit

y,

no

n t

he

rma

l s

pe

ctr

um

&

Ra

pid

va

ria

bil

ity,

no

n t

he

rma

l s

pe

ctr

um

& z

~

z ~

1

1

⇒ ⇒⇒⇒⇒ ⇒⇒⇒re

lati

vis

tic

so

urc

e (

rela

tiv

isti

c s

ou

rce

(Γ ΓΓΓΓ ΓΓΓ≳ ≳≳≳≳ ≳≳≳

10

01

00

) ) (c

om

pa

ctn

es

s p

rob

lem

:

(co

mp

ac

tne

ss

pro

ble

m:

Sc

hm

idt

Sc

hm

idt

19

78

19

78

; F

en

imo

re e

t a

l.

; F

en

imo

re e

t a

l. 1

99

31

99

3;

Wo

od

s &

Lo

eb

;

Wo

od

s &

Lo

eb

19

95

19

95

;…)

;…)

νν

Bep

po

SA

X &

th

e d

isco

very

of

GR

B A

fterg

low

B

ep

po

SA

X &

th

e d

isco

very

of

GR

B A

fterg

low

(1997)

(1997)

W

ide F

ield

Cam

era

: W

ide F

ield

Cam

era

: 4

04

0°°××

40

40°°,,

22--3

0 k

eV

30

ke

V

(+ P

DS

sh

ield

ing

(+

PD

S s

hie

ldin

g ––

ne

arl

y a

ll sky @

ne

arl

y a

ll sky @

10

0

10

0 --

60

0 k

eV

60

0 k

eV

))

N

arr

ow

Fie

ld Instr

um

ents

Narr

ow

Fie

ld Instr

um

ents

::((~

1’

~1

’--0

.50

.5°°))

0.1

0.1

--3

00

ke

V3

00

ke

V

Bep

po

SA

X &

th

e d

isco

very

of

GR

B A

fterg

low

Bep

po

SA

X &

th

e d

isco

very

of

GR

B A

fterg

low

W

FC

WF

C

gro

und

gro

und

poin

t N

FI

poin

t N

FI

gro

und

gro

und (

ho

urs

)(h

ou

rs)

Its a

bili

ties led to

Its a

bili

ties led to a

fterg

low

aft

erg

low

dete

ction (

1997)

in

dete

ction (

1997)

in

XX--r

ays

rays, , o

ptica

lo

ptica

l, , ra

dio

rad

io(f

or

long G

RB

s

(for

long G

RB

s --

LG

RB

s)

LG

RB

s)

T

his

led to r

edshift m

easure

ments

: cle

ar

cut

This

led to r

edshift m

easure

ments

: cle

ar

cut

dete

rmin

ation o

f th

e d

ista

nce/e

nerg

y (

LG

RB

s)

dete

rmin

ation o

f th

e d

ista

nce/e

nerg

y (

LG

RB

s)

dete

rmin

ation o

f th

e d

ista

nce/e

nerg

y (

LG

RB

s)

dete

rmin

ation o

f th

e d

ista

nce/e

nerg

y (

LG

RB

s)

EEγ,iso

γ,iso~~

10

10

52

52--1

010

54

54

erg

erg

, , narr

ow

jets

:narr

ow

jets

:EE

γγ~

10

~ 1

05

1

51

erg

erg

A

fterg

low

observ

ations p

rovid

ed m

any n

ew

A

fterg

low

observ

ations p

rovid

ed m

any n

ew

constr

ain

ts o

n

constr

ain

ts o

n b

eam

ing

beam

ing (

na

rro

w je

ts θ

(na

rro

w je

ts θ

j j ~

3~

3°°--

30

30°°))

, ,

event ra

te

event ra

te (

~1

0(~

10

−5

.5−

5.5

yr

yr

−1

−1

Ga

laxy

Ga

laxy

−1

−1)),

, host gala

xie

s

host gala

xie

s

(sta

r fo

rmin

g)

(sta

r fo

rmin

g),,

exte

rnal density

exte

rnal density (

~1

0(~

10

--3

3 --1

01

022

cm

cm

--33)),

,

Supern

ova c

onnection

Supern

ova c

onnection, , etc

.etc

.

Aft

erg

low

Observ

ations:

Aft

erg

low

Observ

ations: pre

pre

--Sw

ift

Sw

ift

(basic

featu

res the m

odel needs to p

roduce)

(basic

featu

res the m

odel needs to p

roduce)

XX

--rayray,

, o

pti

cal

op

tica

l&

&

rad

iora

dio

emis

sio

n o

ver

(p

reem

issi

on

ov

er (

pre

--Swift

Swift)

)

day

sd

ays,

, w

eek

sw

eek

s&

&

mo

nth

sm

on

ths,

res

pec

tiv

ely,

aft

er G

RB

, re

spec

tiv

ely,

aft

er G

RB

Light curves

Light curves

: : p

ow

erp

ow

er--l

aw d

ecay

law

dec

ay

X-r

ay

Op

tic

al

X-r

ay

Fox e

t al.

(2003)

Piro (

1999)

Som

e a

fterg

low

s s

how

an

Achro

matic S

teepenin

g o

f

the L

ight C

urv

e

(“Je

t B

rea

k”)

Op

tica

l li

gh

t cu

rve

of

Op

tica

l li

gh

t cu

rve

of

GR

B 9

90

51

0G

RB

99

05

10

Op

tica

l li

gh

t cu

rve

of

Op

tica

l li

gh

t cu

rve

of

GR

B 0

30

32

9G

RB

03

03

29

~t-

1

GR

B 9

90

51

0G

RB

99

05

10

(Har

riso

n e

t al

. 1

99

9)

(Har

riso

n e

t al

. 1

99

9)

(Go

rosa

bel

et

al. 2

00

6)

(Go

rosa

bel

et

al. 2

00

6)

~t-

2-t

-2.5

Sp

ectr

um

& L

inear

Po

lari

zati

on

Sp

ectr

um

& L

inear

Po

lari

zati

on

S

pe

ctr

um

:S

pe

ctr

um

:co

nsis

ts o

f co

nsis

ts o

f s

ev

era

l p

ow

er

law

se

gm

en

tss

ev

era

l p

ow

er

law

se

gm

en

ts

& is w

ell

fit b

y

& is w

ell

fit b

y s

yn

ch

rotr

on

syn

ch

rotr

on

em

issio

ne

mis

sio

n

Linear polarization of

Linear polarization of ~ 1%

~ 1%--3%3%

was detected in several

was detected in several

optical/NIR afterglows

optical/NIR afterglows⇒ ⇒⇒⇒⇒ ⇒⇒⇒

likely

likelysynchrotron

synchrotronem

ission

emission

GR

B

GR

B 9

70

50

89

70

50

8

Linear Polarization

Linear Polarization

Sp

ec

tru

mS

pe

ctr

um

GR

B

GR

B 9

70

50

89

70

50

8

Sp

ectr

um

at

Sp

ectr

um

at

12

12

..1

1 d

ays

day

s

(Gal

ama

et a

l.

(Gal

ama

et a

l. 1

99

81

99

8))

(Co

vin

o e

t al

. 2

00

3)

(Co

vin

o e

t al

. 2

00

3)

Th

e S

ize o

f th

e A

fterg

low

Im

ag

eT

he S

ize o

f th

e A

fterg

low

Im

ag

e

Qu

en

ch

ing

of d

iffr

active

scin

tilla

tio

ns a

fte

r ~

30

da

ys

in th

e r

ad

io a

fte

rglo

w o

f G

RB

97

05

08

⇒R⊥

~ 1

01

7cm

T

he

ra

dio

aft

erg

low

of G

RB

03

03

29

wa

s (

ma

rgin

ally

)

reso

lve

d d

ire

ctl

yu

sin

g t

he

VL

BA

(T

aylo

r e

t a

l. 0

4,0

5)

Indirect: Scintillation

Indirect: Scintillation

Dir

ec

t: V

LB

A

spec

tal

slo

pe

spec

tal

slo

pe

4.8

4.8

--8.4

GH

z8.4

GH

zGRB 970508

GR

B 0

30

30

9 (

zG

RB

03

03

09

(z

==0

.17

)0

.17

)

VL

BA

@ 1

.4, 8

.4 G

Hz

VL

BA

@ 1

.4, 8

.4 G

Hz

(Tay

lor

et a

l. 2

00

5)

(Tay

lor

et a

l. 2

00

5)

spec

tal

slo

pe

spec

tal

slo

pe

4.8

4.8

--8.4

GH

z8.4

GH

zGRB 970508

(Fra

il e

t al

. 2

00

0)

(Fra

il e

t al

. 2

00

0)

(Wax

man

et

al. 1

99

8)

(Wax

man

et

al. 1

99

8)

Lig

ht

Cu

rve

Lig

ht

Cu

rve

8.4

GH

z8.4

GH

z

Th

e S

ize o

f th

e A

fterg

low

Im

ag

eT

he S

ize o

f th

e A

fterg

low

Im

ag

e

Qu

en

ch

ing

of d

iffr

active

scin

tilla

tio

ns a

fte

r ~

30

da

ys

in th

e r

ad

io a

fte

rglo

w o

f G

RB

97

05

08

⇒R⊥

~ 1

01

7cm

T

he

ra

dio

aft

erg

low

of G

RB

03

03

29

wa

s (

ma

rgin

ally

)

reso

lve

d d

ire

ctl

yu

sin

g t

he

VL

BA

(T

aylo

r e

t a

l. 0

4,0

5)

Dir

ec

t: V

LB

AD

irect

evid

en

ce f

or

rela

tivis

tic m

oti

on

& d

ecele

rati

on

du

rin

g t

he a

fterg

low

GR

B

GR

B 0

30

30

9

03

03

09

(z(z

==00

..17

17

))

VL

BA

@

VL

BA

@ 11

..44, , 88

..4

4 G

Hz

GH

z

(Tay

lor

et a

l.

(Tay

lor

et a

l. 2

00

52

00

5))

(Pih

lstr

öm

et

al. 2007)

(Lo

ng

) G

RB

–S

N (

Typ

e I

c)

Co

nn

ecti

on

F

irm

ly e

sta

blis

hed the c

onnection b

etw

een long

Firm

ly e

sta

blis

hed the c

onnection b

etw

een long

GR

Bs a

nd c

ore

colla

pse S

upern

ovae (

in

GR

Bs a

nd c

ore

colla

pse S

upern

ovae (

in 2

003

2003; ;

circum

sta

ntial or

less c

onclu

siv

e e

vid

ence e

xited e

arlie

rcircum

sta

ntial or

less c

onclu

siv

e e

vid

ence e

xited e

arlie

r))

P

rogenitor:

massiv

e s

tar

sripped o

f its

Pro

genitor:

massiv

e s

tar

sripped o

f its HH

&

& H

eH

e

S

upport

s the “

Colla

psar”

model, in w

hic

h a

BH

S

upport

s the “

Colla

psar”

model, in w

hic

h a

BH

is form

ed d

uring the c

olla

pse o

f a m

assiv

e s

tar

is form

ed d

uring the c

olla

pse o

f a m

assiv

e s

tar

is form

ed d

uring the c

olla

pse o

f a m

assiv

e s

tar

is form

ed d

uring the c

olla

pse o

f a m

assiv

e s

tar

(Hjo

rth

et a

l. 2

00

3)

GR

B T

heo

ry:

GR

B T

heo

ry:

Fir

eb

all

vs.

Po

yn

tin

g F

lux

Fir

eb

all

vs.

Po

yn

tin

g F

lux

Com

pact

Sourc

e

Inte

rnal S

hocks

R~

10

13-1

01

5cm

Pro

mp

t G

RB

Aft

erg

low

Exte

rna

l

X-r

ays

Op

tica

l

Ra

dio

Re

ve

rse

sh

ock*O

ptica

l

Ra

dio

eje

cta

† S

he

mi &

Pir

an

90

,

Go

od

ma

n 8

6,

Pa

czyn

ski 8

6,…

*Me

sza

ros &

Re

es 9

2,

Ka

tz 9

4, S

ari

& P

ira

n 9

5

reconnection

(or

oth

er

EM

insta

bili

ty)

R ~

10

16-1

01

7 c

m

Par

ticl

e ac

cele

rati

on

⇒⇒γ-

rays

(synch

rotr

on?)

Exte

rna

l

me

diu

mF

orw

ard

Sh

ock

(Re

es &

Me

sza

ros 9

2)

X-r

ays

Op

tica

l

Ra

dio

sh

ock

††U

so

v 9

4,

Th

op

so

n 9

4,

Me

sza

ros &

Re

es 9

7,

Ka

tz 9

7,…

Magnetic

bubble

Lyu

tiko

v &

Bla

nd

ford

02

,03

Aft

erg

low

Th

eo

ry:

Dyn

am

ics

1. A

sp

heri

cal o

utf

low

(re

lati

vis

tic

an

alo

g o

f S

NR

)

The outflow is decelerated

The outflow is decelerated

by a reverse shock

by a reverse shock

When most of the energy is

When most of the energy is

1

forw

ard

shock

A

co

mp

act

sou

rce

ejec

ts a

rel

ativ

isti

c o

utf

low

A c

om

pac

t so

urc

e ej

ects

a r

elat

ivis

tic

ou

tflo

w

D

issi

pat

ion

wit

hin

th

e o

utf

low

cau

ses

the

pro

mp

t G

RB

D

issi

pat

ion

wit

hin

th

e o

utf

low

cau

ses

the

pro

mp

t G

RB

a

rela

tiv

isti

c a

rela

tiv

isti

c forw

ard shock

forw

ard shock s

wee

ps

up

ex

tern

al m

ediu

m

swee

ps

up

ex

tern

al m

ediu

m

When most of the energy is

When most of the energy is

transferred to the shocked

transferred to the shocked

external medium the flow

external medium the flow

approaches self

approaches self--similarity

similarity

(Blandford & M

cKee 1976)

(Blandford & M

cKee 1976)

Finally the flow becomes

New

tonian(Sedov

(Sedov--Taylor)

Taylor)

3

CD

1

2

4

shock

revers

eshock

1. U

np

ert

urb

ed

ext.

med

ium

2. S

ho

cked

exte

rnal

med

ium

3. S

ho

cked

eje

cta

4. F

reely

exp

an

din

g e

jecta

sourc

e

Em

issio

n: S

ynchro

tron R

adia

tion

R

elat

ivis

tic

elec

tron

s g

yra

tin

g i

n a

mag

net

ic f

ield

Rel

ativ

isti

c el

ectr

on

s g

yra

tin

g i

n a

mag

net

ic f

ield

T

he

elec

trons

are

pre

sum

ably

sh

ock

The

elec

trons

are

pre

sum

ably

sh

ock

--acc

eler

ated

to

acce

lera

ted t

o

a p

ow

era

pow

er--l

aw d

istr

ibu

tio

n

law

dis

trib

uti

on d

N/d

dN

/dγγ ee∝∝γγ ee

--p

p ((γγ

ee>>γγ mm

))

C

onven

ient

par

amet

eriz

atio

n o

f our

ignora

nce

: C

onven

ient

par

amet

eriz

atio

n o

f our

ignora

nce

: th

e th

e

elec

trons

& t

he

mag

net

ic f

ield

are

ass

um

ed t

o h

old

el

ectr

ons

& t

he

mag

net

ic f

ield

are

ass

um

ed t

o h

old

el

ectr

ons

& t

he

mag

net

ic f

ield

are

ass

um

ed t

o h

old

el

ectr

ons

& t

he

mag

net

ic f

ield

are

ass

um

ed t

o h

old

frac

tions

frac

tionsεε ee

&

& εε

BBof

the

inte

rnal

ener

gy

of

the

inte

rnal

ener

gy

In

div

idual

ele

ctro

n:

Indiv

idual

ele

ctro

n:

PPνν∝∝νν

1/3

1/3

@@νν

<

< νν

syn

syn∝∝γγB

’B

’γγee22

B

reak

fre

qu

enci

es:

Bre

ak f

req

uen

cies

:ννmm

==νν

syn

syn((γγ

mm),

),

ννcc==νν

syn

syn((γγ

cc), ), νν

aa

S

yn

chro

tron

Sy

nch

rotr

on

--sel

f C

om

pto

n m

ay a

lso

be

rele

van

tse

lf C

om

pto

n m

ay a

lso

be

rele

van

t

Sp

ectr

a &

Lig

ht

Cu

rves

Fν ννν∝ ∝∝∝

tα ν ννν

β

(JG

& S

ari

2002)

(JG

& S

ari

2002)

(Sar

i, P

iran

&

(Sar

i, P

iran

&

Nar

ayan

1998)

Nar

ayan

1998)

Fν ννν∝ ∝∝∝

tν ννν

Ori

gin

of

Dif

fere

nt

Em

issio

n C

om

po

nen

ts:

T

he

Th

e long lived

long lived

afte

rglo

w

afte

rglo

w emission

emission

last

ing

day

s,

last

ing

day

s,

wee

ks,

& m

on

ths

in t

he

Xw

eek

s, &

mo

nth

s in

th

e X

--ray

, o

pti

cal

& r

adio

is

ray,

op

tica

l &

rad

io i

s

attr

ibu

ted

to

th

e at

trib

ute

d t

o t

he forw

ard shock

forw

ard shock

th

eth

ereverse shock

reverse shock

is b

elie

ved

to

pro

du

ce t

he

is b

elie

ved

to

pro

du

ce t

he

““optical flash

optical flash

” ” an

dan

d““radio flare

radio flare

””em

issi

on

,em

issi

on

,w

ho

se p

ola

riza

tio

n p

rob

es B

wh

ose

po

lari

zati

on

pro

bes

B--f

ield

str

uct

ure

in

ou

tflo

wfi

eld

str

uct

ure

in

ou

tflo

w

Th

e s

imp

lest

sp

heri

cal m

od

el w

as v

ery

su

ccessfu

l in

exp

lain

ing

aft

erg

low

ob

serv

ati

on

s d

uri

ng

th

e f

irst

~ 2

years

aft

er

the d

ete

cti

on

of

aft

erg

low

in

1997

GR

B 9

90

12

3

Rad

io F

lare

(Ku

lka

rni e

t a

l. 9

9)

Op

tical F

lash

(Sa

ri &

Pir

an

19

99

)

wh

ose

po

lari

zati

on

pro

bes

Bw

ho

se p

ola

riza

tio

n p

rob

es B

--fie

ld s

tru

ctu

re i

n o

utf

low

fiel

d s

tru

ctu

re i

n o

utf

low

aft

er

the d

ete

cti

on

of

aft

erg

low

in

1997

Com

plic

ations:

Com

plic

ations:

variants

of basic

model

variants

of basic

model

mo

tiva

tio

n: b

oth

th

eo

retica

l &

ob

se

rva

tio

na

lm

otiva

tio

n: b

oth

th

eo

retica

l &

ob

se

rva

tio

na

l

R

ad

iati

ve lo

sses

Rad

iati

ve lo

sses

(Bla

nd

ford

& M

cK

ee

67

; C

oh

en

, P

ira

n &

(B

lan

dfo

rd &

McK

ee

67

; C

oh

en

, P

ira

n &

Sa

ri 9

8;

Pa

na

ite

scu

& M

esza

ros 9

8;

Me

sza

ros,

Re

es &

Wije

rs 9

8)

Sa

ri 9

8;

Pa

na

ite

scu

& M

esza

ros 9

8;

Me

sza

ros,

Re

es &

Wije

rs 9

8)

W

ere

exp

ecte

d th

eo

retica

lly in

th

e e

arl

y a

fte

rglo

w

We

re e

xp

ecte

d th

eo

retica

lly in

th

e e

arl

y a

fte

rglo

w

in

vo

ke

d to

re

du

ce

th

e h

igh

pro

mp

t in

vo

ke

d to

re

du

ce

th

e h

igh

pro

mp

t γγ--

ray e

ffic

ien

cy

ray e

ffic

ien

cy

W

ind

Win

d--lik

e e

xte

rnal density

like e

xte

rnal density ∝∝

RR--22

(Ch

eva

lier

& L

i 2

00

0)

(Ch

eva

lier

& L

i 2

00

0)

W

ind

Win

d--lik

e e

xte

rnal density

like e

xte

rnal density ∝∝

RR--22

(Ch

eva

lier

& L

i 2

00

0)

(Ch

eva

lier

& L

i 2

00

0)

M

otiva

tio

n: e

xp

ecte

d fo

r m

assiv

e s

tar

pro

ge

nito

rM

otiva

tio

n: e

xp

ecte

d fo

r m

assiv

e s

tar

pro

ge

nito

r

Jets

Jets

: narr

ow

ly c

olli

mate

d o

utflo

w

: narr

ow

ly c

olli

mate

d o

utflo

w (

Rh

oa

ds

(Rh

oa

ds

97

,9

7,9

9;…

)9

9;…

)

M

otiva

tio

n: in

an

alo

gy t

o o

the

r re

lativis

tic s

ou

rce

s

Mo

tiva

tio

n: in

an

alo

gy t

o o

the

r re

lativis

tic s

ou

rce

s

&&re

du

ce

s t

ota

l e

ne

rgy o

utp

ut

in

red

uce

s t

ota

l e

ne

rgy o

utp

ut

in γγ

--ra

ys

rays

P

red

icte

d a

“je

t b

rea

k”

wh

ich

wa

s s

oo

n o

bse

rve

dP

red

icte

d a

“je

t b

rea

k”

wh

ich

wa

s s

oo

n o

bse

rve

d

What causes a Jet Break in GRB Afterglows

Γ

Γ−1

Aberr

ation o

f lig

ht

or

‘rela

tivis

tic b

eam

ing’

Sourc

e

fram

e

Observ

er

fr

am

e

Re

lati

vis

tic

So

urc

e:

Conic

al

jet

observ

er

1/Γ

The

ob

serv

er s

ees

most

ly e

mis

sion

from

wit

hin

an a

ngle

of

1/

1/ΓΓ

around

the

line

of

sight

1/Γ

Direction to observer

The

edges

of

the

jet

bec

om

e

vis

ible

when

ΓΓdro

ps

bel

ow

1/

1/θθ

jet

jet, ca

usi

ng a

jet

bre

ak

For vv⊥⊥

~ c

~ c

,θθ

jet

jet

~ 1

/~

1/ΓΓ

so t

her

e is

not

much

“m

issi

ng”

emis

sion f

rom

θθ>>θθ

jet

jet&

the

jet

bre

ak i

s due

to t

he

dec

reas

ing d

E/d

dE

/dΩΩ

+ f

aste

r fa

ll i

nΓΓ

(t)

(t)

Th

e Swift

Era

: (l

au

nch

ed

No

ve

mb

er

20

, 2

00

4)

O

bse

rves

a G

RB

in

γ-r

ays,

th

en s

lew

s to

its

po

siti

on

auto

no

meo

usl

y, w

hit

hin

ten

s o

f se

no

nd

s, &

ob

serv

es

in X

-ray

s, U

ltra

-Vio

let

(UV

) an

d o

pti

cal

D

etec

ts ~

10

0 G

RB

/yr

+ X

-ray

aft

erg

low

fo

r m

ost

It

s ea

rly

aft

erg

low

ob

serv

atio

ns

fill

ed t

he

gap

Its

earl

y a

fter

glo

w o

bse

rvat

ion

s fi

lled

th

e g

ap

bet

wee

n t

he

pro

mp

t γ-

ray

em

issi

on

an

d p

re-S

wif

t

“lat

e” a

fter

glo

w o

bse

rvat

ion

s, h

ou

rs a

fter

th

e G

RB

D

isco

ver

ed u

nex

pec

ted

beh

avio

r o

f ea

rly

aft

erg

low

L

ed t

o t

he

dis

cov

ery

of afterglow f

romshort G

RB

s

h

ost

gal

axie

s, r

edsh

ifts

, en

erg

y, ra

te, p

rog

enit

ors

?

Early X

Early X

--ray A

fterg

low

s fro

m S

wift:

ra

y A

fterg

low

s fro

m S

wift:

Post

jet

break

Shallow

decay

t0-t-1

Rapid

decay

t-5-t-3

“usual”

decay

t-1-t-1.5

Tail

of

pro

mpt

em

issio

n

~102.5s

~104s

t jet

(O’b

rien

et

al. 2

00

6)

(O’b

rien

et

al. 2

00

6)

(Vau

gh

an e

t al

. 2

00

6)

(Vau

gh

an e

t al

. 2

00

6)

Possible Explanations for the Shallow Decay

ε x(t

)Ek,iso

(t)

tFx(t

)≈

4πdL2(1+z)

β−α−1 w

her

e ε x

(t)≡t Lx(t

)

Ek,iso

(t)

is

the

afte

rglo

w

effi

cien

cy (

frac

tio

n o

f k

inet

ic e

ner

gy

rad

iate

d i

n t

he

dy

nam

ical

tim

e).

Du

rin

g t

he

shal

low

dec

ay p

has

e εx(t

)Ek,iso

(t)∝tFx(t

) in

crea

ses

wit

h t

ime.

Fo

r νx>

max

(νm,νc)

an

d p>

2, u

nd

er s

tan

dar

d a

fter

glo

w t

heo

ry ε x(t

)

dec

rese

s w

ith

tim

e, an

d t

her

efo

re Ek,iso

(t)

mu

st i

ncr

ease

wit

h t

ime.

(JG

, K

önig

l &

Piran 2

006)

31

Alt

ern

ativ

ely

, εx(t

) ca

n i

ncr

ease

in

tim

e u

nd

er l

ess

stan

dar

d a

ssu

mp

tio

ns

Possible Explanations for the Shallow Decay

E

nerg

y in

jecti

on

into

afterg

low

: (N

ousek e

t al. 0

6)

I.

Co

ntin

uo

us r

ela

tivis

tic w

ind

L∝

t-0

.5(m

ag

ne

tar?

)

II

.S

low

er

ma

teri

al e

jecte

d d

uri

ng

th

e p

rom

pt

GR

B

gra

du

ally

ca

tch

es u

p t

he

de

ce

lera

tin

g a

fte

rglo

w s

ho

ck

A

fterg

low

eff

icie

ncy incre

ases w

ith t

ime

(va

ryin

g

sh

ock m

icro

-ph

ysic

s p

ara

me

ters

; JG

, K

ön

igl &

Pira

n 0

6)

sh

ock m

icro

-ph

ysic

s p

ara

me

ters

; JG

, K

ön

igl &

Pira

n 0

6)

O

bserv

er

outs

ide e

mitting r

egio

n(E

ich

ler

& J

G 0

6)

(JG

, R

am

irez-R

uiz

& P

ern

a 0

5)

Possible Explanations for the Shallow Decay

E

nerg

y in

jecti

on

into

afterg

low

: (N

ousek e

t al. 0

6)

I.

Co

ntin

uo

us r

ela

tivis

tic w

ind

L∝

t-0

.5(m

ag

ne

tar?

)

II

.S

low

er

ma

teri

al e

jecte

d d

uri

ng

th

e p

rom

pt

GR

B

gra

du

ally

ca

tch

es u

p t

he

de

ce

lera

tin

g a

fte

rglo

w s

ho

ck

A

fterg

low

eff

icie

ncy incre

ases w

ith t

ime

(va

ryin

g

sh

ock m

icro

-ph

ysic

s p

ara

me

ters

; JG

, K

ön

igl &

Pira

n 0

6)

It isn

’t c

lear

wh

ich

of

these e

xp

lan

ati

on

s,

if a

ny, is

in

deed

th

e d

om

inan

t cau

se f

or

the s

hallo

w d

ecay p

hase

sh

ock m

icro

-ph

ysic

s p

ara

me

ters

; JG

, K

ön

igl &

Pira

n 0

6)

O

bserv

er

outs

ide e

mitting r

egio

n(E

ich

ler

& J

G 0

6)

T

wo c

om

ponent je

t:w

ide

jet:

ΓΓ00

~

~ 2

02

0--5

05

0

nar

row

jet

: ΓΓ

00>

>

10

01

00

observ

er

θθww

θθnn

tt dec

dec∝∝ΓΓ

00--2

(42(4

--k)/

(3k)/

(3--4

)4)

for

forρρ

ext

ext∝∝

rr--kk⇒⇒

tt dec

,ndec

,n≪≪

tt dec

,wdec

,w

(JG

, K

önig

l (J

G,

König

l

& P

iran

06)

& P

iran

06)

X-r

ay F

lare

s:

pro

lon

ged

so

urc

e a

cti

vit

y?

S

ho

rt t

ime

scal

e (∆

t≪

t) L

arg

e am

pli

tud

e (∆

F≳

F)

rule

ou

t an

aft

erg

low

ori

gin

T

hey

are

mo

st l

ikel

y d

ue

to

Th

ey a

re m

ost

lik

ely

du

e to

long lived central source

long lived central source

acti

vit

yac

tiv

ity

(lat

e(l

ate

tim

eti

me

fall

bac

k?

fall

bac

k?))

Lat

eL

ate

&&lo

cali

zed

lo

cali

zed

Lat

eL

ate

&&lo

cali

zed

lo

cali

zed

dis

sip

atio

n e

ven

ts w

ith

in

dis

sip

atio

n e

ven

ts w

ith

in

the

ou

tflo

w?

the

ou

tflo

w?

(No

use

k e

t al

. (N

ou

sek

et

al. 2

00

62

00

6))

(Kri

mm

, JG

, et

al.

20

06

)(K

rim

m, JG

, et

al.

20

06

)

Sh

ort

GR

Bs

~

~ 11

//4

4 o

f B

AT

SE

bu

rsts

of

BA

TS

E b

urs

ts

Sh

ort

GR

Bs

wit

h g

oo

d l

oc

alis

ati

on

sSince

2005 several sh

ort bursts have been loca

lised by

Swift and

HETE-II and

seem, by G

RB stand

ard

s,

mod

erate ene

rgy (~1048-1050ergs), mod

erate redsh

ift

(z~0.1-0.5) events, associated w

ith a variety of host

galaxies (and

no associated supernovae).

consistent w

ith binary coa

lescence (NS-NS, NS-BH)

origin, but still inconclusive

050709B

origin, but still inconclusive

050709B

Fox e

t al.

Sh

ort

GR

Bs

wit

h g

oo

d l

oc

alis

ati

on

s…but

these

tend

not

to hav

e been ve

ry typ

ical

shor

t bur

sts in the har

dne

ss-d

urat

ion se

nse, an

d

there

is evidenc

e that

som

e of th

e oth

er sh

ort

bur

sts ar

e higher ene

rgy, higher re

dsh

ift eve

nts.

GRB 050813

•No op

tica

l afterglow.

•XRT position sugg

ests po

ssible association w

ith

galaxies at z~

0.7, although

even ne

arer (on sky)

galaxies at z~

1.8 (Berger).

GRB 051221

•A brigh

t sh

ort burst, at z~

0.55. Eiso~2x1051erg

(Sod

erb

erg

et al. 2006)

So

me O

pen

Qu

esti

on

s:

W

hat

are

the

pro

gen

ito

rs o

f sh

ort

GR

Bs?

What

are

the

pro

gen

ito

rs o

f sh

ort

GR

Bs?

H

ow

are

GR

B j

ets

lau

nch

ed a

nd

coll

imat

ed?

How

are

GR

B j

ets

lau

nch

ed a

nd

coll

imat

ed?

W

hat

is

the

ou

tflo

w c

om

po

siti

on (

What

is

the

ou

tflo

w c

om

po

siti

on (

ee++ee−−

pp--e

, B

e, B

--fie

lds

fiel

ds)

?)?

W

hat

is

the

γW

hat

is

the

γ--ra

y e

mis

sio

n m

echan

ism

?ra

y e

mis

sio

n m

echan

ism

?

T

he

(angula

r) s

truct

ure

& d

ynam

ics

of

GR

B j

ets

The

(angula

r) s

truct

ure

& d

ynam

ics

of

GR

B j

ets

T

he

(angula

r) s

truct

ure

& d

ynam

ics

of

GR

B j

ets

The

(angula

r) s

truct

ure

& d

ynam

ics

of

GR

B j

ets

P

hysi

cs o

f co

llis

ion

les

rela

tiv

isti

c sh

ock

s (p

arti

cle

Physi

cs o

f co

llis

ion

les

rela

tiv

isti

c sh

ock

s (p

arti

cle

acce

lrat

ion, m

agn

etic

fie

ld a

mp

lifi

cati

on,…

)ac

celr

atio

n, m

agn

etic

fie

ld a

mp

lifi

cati

on,…

)

D

o G

RB

s p

rod

uce

th

e h

igh

est

ener

gy

co

smic

ray

s?D

o G

RB

s p

rod

uce

th

e h

igh

est

ener

gy

co

smic

ray

s?

D

o l

on

g G

RB

s fo

rm B

H o

r m

illi

seco

nd

mag

net

ars?

Do

lo

ng

GR

Bs

form

BH

or

mil

lise

con

d m

agn

etar

s?

Pro

sp

ects

fo

r th

e F

utu

re (

I)

Short

GR

B p

rog

enit

ors

: m

ore

ob

serv

atio

ns,

min

iS

hort

GR

B p

rog

enit

ors

: m

ore

ob

serv

atio

ns,

min

i--S

N,

SN

,

gra

vit

atio

nal

wav

es (

Adv

ance

d L

IGO

, L

ISA

; gra

vit

atio

nal

wav

es (

Adv

ance

d L

IGO

, L

ISA

;

‘sm

okin

g g

un

’ fo

r b

inar

y m

erger

)‘s

mokin

g g

un

’ fo

r b

inar

y m

erger

)

L

aunch

ing &

co

llim

atio

n o

f G

RB

jet

s: G

RM

HD

L

aunch

ing &

co

llim

atio

n o

f G

RB

jet

s: G

RM

HD

sim

ula

tions,

sel

fsi

mula

tions,

sel

f--si

mil

ar a

nal

yti

c so

luti

ons

sim

ilar

an

alyti

c so

luti

ons

O

utf

low

com

po

siti

on

: co

nst

rain

ts f

rom

ob

serv

atio

ns,

O

utf

low

com

po

siti

on

: co

nst

rain

ts f

rom

ob

serv

atio

ns,

hig

hhig

h--e

ner

gy n

eutr

ino

s (I

ceC

ub

e,…

) or

cosm

ic r

ays

ener

gy n

eutr

ino

s (I

ceC

ub

e,…

) or

cosm

ic r

ays

(Auger

,…)

(Auger

,…)

--‘s

mok

ing

gu

n’

for

pro

tons

or

hea

vy i

ons

‘sm

ok

ing

gu

n’

for

pro

tons

or

hea

vy i

ons

γγ--

ray e

mis

sio

n m

ech

anis

m:

Fer

mi

Gam

ma

ray e

mis

sio

n m

ech

anis

m:

Fer

mi

Gam

ma--

Ray

R

ay

Sp

ace

Tel

esco

pe,

lau

nch

ed J

une

20,

2008, w

ill

hel

p

Sp

ace

Tel

esco

pe,

lau

nch

ed J

une

20,

2008, w

ill

hel

p

Ferm

i G

am

ma-R

ay S

pace T

ele

sco

pe

(Fo

rme

rly G

LA

ST;

lau

nch

ed

on

Ju

ne

11

, 2

00

8):

Fermi Gamma-ray Burst Monitor

(GBM): 10 keV

–25 M

eV, full sky

Slightly less sensitive than BATSE

expected to detect ~ 200 GRB/yr

(≳ ≳≳≳60 in the LAT FoV)

Large Area Telescope (LAT):

≳ ≳≳≳

Large Area Telescope (LAT):

20 M

eV –300 GeV

,FoV ~ 2.4 sr

LA

T

Fo

V

GB

M

Fo

V

Pro

sp

ects

fo

r th

e F

utu

re (

II)

S

truct

ure

& d

yn

amic

s o

f G

RB

jet

s: m

odel

ing o

f S

truct

ure

& d

yn

amic

s o

f G

RB

jet

s: m

odel

ing o

f

ob

serv

atio

ns,

ob

serv

atio

ns,

spec

ial

rela

tiv

isti

c hydro

spec

ial

rela

tiv

isti

c hydro

--sim

ula

tions,

sim

ula

tions,

self

self

--sim

ilar

sim

ilar

solu

tion

sso

luti

on

s

P

hysi

cs o

f co

llis

ion

les

rela

tiv

isti

c sh

ock

s: a

nal

yti

c or

Physi

cs o

f co

llis

ion

les

rela

tiv

isti

c sh

ock

s: a

nal

yti

c or

sem

ise

mi--

anal

yti

c st

udie

s +

par

ticl

e in

cel

l si

mula

tions

anal

yti

c st

udie

s +

par

ticl

e in

cel

l si

mula

tions

H

igh

est

ener

gy

co

smic

ray

s: m

od

elin

g t

he

Hig

hes

t en

erg

y c

osm

ic r

ays:

mo

del

ing

th

e

ob

serv

atio

ns

of

the

Au

ger

co

smic

ray

ob

serv

ato

ryo

bse

rvat

ion

s o

f th

e A

ug

er c

osm

ic r

ay o

bse

rvat

ory

B

H o

r m

agn

etar

s fr

om

lo

ng

GR

Bs:

th

eore

tica

l w

ork

B

H o

r m

agn

etar

s fr

om

lo

ng

GR

Bs:

th

eore

tica

l w

ork

(an

aly

tic

& n

um

rica

l m

od

elin

g o

f m

assi

ve

star

(a

nal

yti

c &

nu

mri

cal

mo

del

ing

of

mas

siv

e st

ar

evo

luti

on &

co

llap

se)

+ m

od

elin

g o

bse

rvat

ion

sev

olu

tio

n &

co

llap

se)

+ m

od

elin

g o

bse

rvat

ion

s