Post on 29-Jul-2018
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