An Off-Axis Jet inElectromagnetic
Counterparts to
GW170817?
Kunihito IOKA(Center for Gravitational Physics,YITP, Kyoto U)

2018/3/16

Kunihito IOKA

2Multi-Messenger Era
CosmicPhotonRaynGravitational
Wave

21th Century: Multi-Messenger Era

2018/3/16

Kunihito IOKA

3

GW170817
1st GW from NS2

NS2 = Short GRB?
40yr-old hypothesis~100 sec chirp ⇒ NS-NS

Pacynski 86, Goodman 86
Eichler, Livio, Piran & Schramm 89

R-process elements

Equation of state
Relativity,
Cosmology,…

Lattimer & Schramm 74

2018/3/16

Kunihito IOKA

New Era ofMulti-Messenger
4

Follow-up observations>3000 people
g-ray: ~1.7340.054 sec⇒ sGRB 170817A
UV-Opt-IR: 10.86 hr⇒ Macronova/Kilonova
X, radio: ~10 day⇒ Afterglow
LVC-EM 17
Band: GCN circ., Circles ∝ brightness2018/3/16

Kunihito IOKA

5GW170817 & GRB 170817A
LVC-GBM-INTEGRAL 17

3 (of 12) GBM NaI detectors
T0=1.740.05 sec (68%)
T90=2.00.5 sec

But very very weak

LVC-EM 17
Goldstein+ 17
Savchenko+ 17

Eiso = 51046 erg

2018/3/16

Kunihito IOKA

KI & Nakamura 17weeks~months

X/Radio
afterglow

G-1

Jet-ISM shock

Ejecta-ISM
shock

G-1
Jet
G~100

Cocoonv~0.2-0.4c

Dqqv

Mergerejectav~0.03-0.2c(dynamical/shock/wind)Disk

6~sec>years

Off-axissGRB

X/Radioflare~1day opt.
macronova~10day IR
macronova

2018/3/16

Kunihito IOKA

7

Merger of 1.3-1.4 Msun NS:
EOS=APR4; stiff but relatively softr (g/cm3)

Relatively wider view

Orbital plane©Shibata, Hotokezaka

X-Z plane2018/3/16

Kunihito IOKA

8

Jet Breakout from Ejecta
Ejecta is also
on the poleNagakura+ 14
Murguia-Berthier + 14

Similar to collapsars (long GRBs)
Weak jet ~1046 erg/s cannot break out

2018/3/16

Kunihito IOKA

KI & Nakamura 17

weeks~months

X/Radio
afterglow

G-1

Jet-ISM shock

Ejecta-ISM
shock

G-1
Jet
G~100

Cocoonv~0.2-0.4c

Dqqv

Mergerejectav~0.03-0.2c(dynamical/shock/wind)Disk

9~sec>years

Off-axissGRB

X/Radioflare~1day opt.
macronova~10day IR
macronova

2018/3/16

Kunihito IOKA

10Off-Axis Jet
Eiso(θv) [erg] (10keV-25MeV)

1054
10∆θ=15º∆θ=20º∆θ=25º
Point
Fitting
γ-raysFiducial
GWs

53

1052
1051
1050
1049
1048

1047

Γ=1001046
1045
1044

0qv~Dq⇒ Pointapprox.
is badEiso∝qv-6↓Eiso∝qv-4

510 15 20 25 30 35 40 45 50 55 60
KI & Nakamura 17, 01
LVC-GBM-INTEGRAL 17
Viewing angle θv of the jet
Yamazaki, KI & Nakamura 02, 03, 04

Granot+ 17, Kasliwal+ 17

2018/2/9

Kunihito IOKA (YITP)

11Off-Axis Eiso

equally contributing region

Dq: jet opening angle, qv: viewing angle

2018/3/16

Kunihito IOKA

12Viewing Angle Probability
1h+ ∝ (1+ cos2 i)
2h× ∝ cosi

On-axis GW
is strongi~30 isprobable
Schutz 11
Lamb & Kobayashi 17

GW170817: i<~302018/3/16

Kunihito IOKA

13Time Scales
Time delay Dt−2

⎛ Δt ⎞⎛ Δθ ⎞Rγ < 6 ×10 cm ⎜ ⎟⎜ ⎟⎝ 1 s ⎠⎝ 0.1 ⎠12Durationengineduration

T90 ~ max [tdur , tθ ]Granot+ 17
KI & Nakamura 17

2018/3/16

Kasliwal+ 17
Gottlieb+ 17
Bromberg+ 17

Kunihito IOKA

14

2018/3/16

Kunihito IOKA

15

X-ray Afterglow
Chandra 50ks
trise~9 day
LX,iso~1.1e39 erg/s

Troja+, Margutti+, Haggard+ 17

2018/3/16

Kunihito IOKA

16

Radio Afterglow
6GHz, 9 Sep.

6GHz, 22.6
Aug.-1 Sep.

~30 mJy@6GHz
VLA, ATCA

trise~16 days
Hallinan+, Alexander+ 17

X/Radio ratio ~ Synchrotron p=2.2 (nm<n<nc)2018/3/16

Kunihito IOKA

17

Afterglow Spectrum
Consistent witha single power-law⇒ Synchrotron
nm<n<nc'.) '.*"# $ ∝ & $⇨ e spectrum:, ≈ 2.2

Troja+ 18, Marugutti+ 18, Ruan+ 18,
D’Avanzo+ 18, Lyman+ 18,

2018/3/16

Kunihito IOKA18

Turnovers in Afterglows
a1=0.850.05
a2=-2.1+0.6-1.6
tp=157+22-9 day
Dobie+ 18
d1=0.840.05
d2=-1.60.2
tp=1492 day

Alexander+ 18

Sharp decline ⇒Not a cocoon
Support a jet

2018/3/16

Ghirlanda+ 18

Kunihito IOKA

19

Superluminal Motion
VLBI sky position

vapp~4.10.5 c!
Unresolved
R<0.2pc(1mas),<2pc(10mas)

230 days

Mooley+ 1806.09693

70 days

Not consistent
with a sphericalsourceG~4at t~tpeak

2018/3/16

Kunihito IOKA

KI & Nakamura 17weeks~months

X/Radio
afterglowG-1

Jet-ISM shock

Ejecta-ISMshock

G-1
Jet
G~100Cocoon
v~0.2-0.4c

Dqqv

Mergerejectav~0.03-0.2c(dynamical/shock/wind)

Disk

21

~sec>years

Off-axissGRB

X/Radioflare~1day opt.
macronova~10day IR
macronova

2018/3/16

Kunihito IOKA

22

Slowly Rising Afterglow
Slowly rising
up to ~100d
Inconsistent
with a simple jet

X (GCN22201, 22203, 22206)& Opt (GCN22207) also rise
Mooley+ 17

Energy injection
radial or polar:
Structured jetor cocoon?

2018/3/16

Kunihito IOKA

23

Structured Jet?
Polar energyinjection
Jet+Coccon
orIntrinciallystructured?
Lazzati+ 17

2018/3/16

Kunihito IOKA

Structured Jet?

24

Margutti+ 18
Lazzati+ 17
D’Avanzo+ 18
Lyman+ 18

2018/3/16

Kunihito IOKA

Power-Law Jet?
!" # ∝ % &.( # &.) ⇨ e spectrum: + ≈ 2.2

D’Avanzo+ 17

25

2018/3/16

Kunihito IOKA

Gaussian Jet?
! " = !$ − " ' ⁄2 ")'26

Troja+ 18

2018/3/16

Kunihito IOKA

27

Hardness

Spectrum

Goldstein+ 17

Main pulse
power law (a=-0.620.40)+ cutoff (Epeak=18562keV)
Weak tail34% the fluenceof the main pulse
kT=10.31.5keV
T90

2018/3/16

Kunihito IOKA

28

Scattered sGRB
Thompson scattering by cocoon
Copy spectrum w/ ~MeV cutoff
rsc<1010-1012 cm

Wide angle
Kisaka+ 17
Kisaka+ 15

2018/2/9

Kunihito IOKA (YITP)

29

Surface Brightness
Surface brightness of a structured jet [erg/sr]
0.4
6x1048 E
0.30.2
θsinφ

0.1

nimyr
a5x1048ile
Pr Jet center

4x10Jet coreViewing
angle-0.2-0.3-0.4-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4θcosφd⌦4⇡E (✓)
4 (1cos ✓ )3cos ✓ = sin ✓ cos sin ✓v+ cos ✓ cos ✓v

Most emission
comes from2x1048
the jet edge
48
1x10
outside the core0& not on theviewing angle
3x10480-0.1

48,iso =Z2018/3/16

Kunihito IOKAHigh Energy g-Ray?
l Jet & Afterglow– Extended & plateau emission to ~104-5 sec– Off-axis de-beamingl Central remnant– Magnetarl Merger ejecta– Energy injection from central engine?

30

2017/08/25

Kunihito IOKA

31

Short GRBs are Not Short

Short GRB

Extended emission
2x Energy

GRB050724
Barthelmy+ 05

Too rapid decline:
NOT afterglow
BUT central engine~100 s >>tvis ~ 0.1 s⇒ Fallback
to BH? orMagnetar?

2017/08/25

Kunihito IOKA

32

Plateau Emissiont ~ 10000 s!
tacc
0.1 s

1 r r
cs h1

0.1

r
r
106 cm10h
Fallback? Magnetar?
Gompertz+ 13, 14; Rowlinson+ 13; Li+ 15

Kunihito IOKA

2017/08/25

33

EM Counterparts
If on-axis &FX~FHEg,
VERY EASY
to detect
CTA follow up
even no-detect.
is important
Kisaka, KI & Sakamoto 172018/3/16Kunihito IOKA

34

Limits on GW170817
No detection so far
CTA is more powerful
Murase+ 18

HESS+ 18

2018/3/16

Kunihito IOKA

35

HE g-ray from Afterglow

E=100 GeV
d=40Mpc

Murase+ 18

Afterglow
HE electron+ extended
X-ray emission⇒ ExternalCompton

2018/3/16

Kunihito IOKAHigh Energy g-Ray?
l Jet & Afterglow– Extended & plateau emission to ~104-5 sec– Off-axis de-beamingl Central remnant– Magnetarl Merger ejecta– Energy injection from central engine?

36

2018/3/16

Kunihito IOKA

37

Magnetar
EjectedMNS-NS<< MSN⇒ t<1earlier

Diversityof MNS

2018/10/12

HE counterparts to GWs by K. Ioka

38

Supernova Remnant
RadioX-ray

g-ray

NS merger remnant ~ Supernova remnant⇒ High energy remnant for NS merger?

2018/10/12

HE counterparts to GWs by K. Ioka

39

NS Merger Remnant@tSedov~5yr
RadioIR-Opt X-ray

g-ray

InverseComptonSynchrotron
Takami, Kyutoku & KI 13

EM Counterparts to GWs by Kunihito
IOKA

2015/06/30

Merger Remnant Spectrum@100Mpc

Takami, Kyutoku & KI 1340

2018/3/16

Kunihito IOKA

41

2016/10/11

GW150914-like BHs by K. Ioka

42

Galactic BHs

70 Gpc-3 yr-1

0.01 galaxy Mpc-3

1010 yr~ 70000 Merged BHs/galaxy

2016/10/11

GW150914-like BHs by K. Ioka

43

Galactic BHs

70 Gpc-3 yr-1

0.01 galaxy Mpc-3

1010 yr~ 70000 Merged BHs/galaxy

GW150914-like BHs by K. Ioka

44

Luminosity Function
εmax [eV] ∝ Z
105

1012

1013

1014

σv=40km/s (isolated binaries)

Cold H100

Molecular clo
udII101

Warm H

2II10

Warm H103

II104

Hot H.
.
Luminosity Function M dN/dM

2016/10/111015

1016
vGW=01017

The mostluminous
BH jet is~1036 erg/sin cold HIvGW reduces
Lj by ~1010-1
10271028102910301031103210331034103510361037103810391040.
Jet Luminosity Lj ~ Mc2 [erg s-1]
KI+ 16, see also Tsuna+18

2016/10/11

GW150914-like BHs by K. Ioka

45

Particle Acceleration
Neutron starl Hillas condition

GRB

l LB~4pR2(B2/8p)c∝(BR)2Blandford 00
l Emax>PeV Waxman 04

Gamma-Ray Burst

LHC

E<ZqBRVe1210PeVatron!!!

otpronActive Galactic Nuclei

GalaxyCluster

Barkov+ 12KI+ 16

DarkMatter?

2016/10/11

GW150914-like BHs by K. Ioka

46Log N – Log F
εγ=1εγ=0.01
TeV unID
CTA prospect

104103101

Flux dis. is similar-1⇒ rh ~ 3 pc

-1

10-16 10-15 10-14 10-13 10-12 10-11 10-10 10-9 10-8 10-7
Observed Flux F [erg s-1 cm-2]

KI+ 16

BH nebula size:

Lj
2~ ρV
2 2
4π rh θ cFN∝ -1100

σv=40km/s(isolated binaries)

Fke 2 ∝-li Risk )∝D (>F102

10BHs ⇔TeV unIDs?

N

Cumulative Number N(>F)

105

CTA will see ~300 BHsmost natural vÐeld is in equ
X-ray Nova? sponds to b \very common
Hydrogen-ionization
C. Doneparticular,
equdisk instabilitytion Ñows sincADAF + Standard
which disk
presumOuter disk
is cold
H ionisedgrows,
isknow
slow fall (viscous)
Hydrogen parameterrecombines a- ion opacity
fast riseH
Hawley & B(thermal).m⇒ S-shaped
curve
Balbus1995,
1
fast fall
for thermalisequilibrium(thermal)
the shear stH neutral⇒ X-ray nova-like?
range 0.2È0.3.
slow rise (viscous)
mass of the disc at radius Ra \ Matsumoto+0.25. 172017/03/10

kT (proportional to m 1/4 )6.

inAstro in the GW Era by K. IOKA

47

2018/3/16

Kunihito IOKA

Summaryl sGRB170817 & GRB 170817A– Off-axis jet– Jet structure?, Spectrum?, Mechanism?

l High energy g-ray for CTA– Jet, Afterglow, Magnetar, Merger ejecta– CTA follow-up is importantl BH remnant in our Galaxy– Some TeV unIDs? X-ray novae?

48ThankYou