GW170817: Op4cal/infrared Observa4ons and Kilonovae

Masaomi Tanaka(NAOJ)

総研大集中講義 「マルチメッセンジャー天文学」(2018年9月10-13日@国立天文台)

TENNET: 16174

電磁波各波長・重力波・ニュートリノ・宇宙線の基礎的な検出原理、稼働装置、将来計画などを横断的に学ぶ
ニュートリノ天文学 (吉田 滋さん, 2コマ)
重力波天文学 (麻生 洋一さん、久徳 浩太郎さん)
宇宙線天文学 (多米田 裕一郎さん)
ガンマ線天文学 (水野 恒史さん, 2コマ)
X線天文学 (馬場 彩さん, 2コマ)
光赤外線天文学 (松田 有一さん)
電波天文学 (秦 和弘さん)

GW170817: Op4cal/infrared Observa4ons and Kilonovae• GW170817: mul6-messenger observa6ons• Kilonova and the origin of heavy elements• Future prospects

2

s a BNS as the source of the gravitational-wave sigas the total masses of known BNS systems are been 2.57 M and 2.88 M , with components between
and ⇠1.6 M [47]. Neutron stars in general have prey measured masses as large as 2.01 ± 0.04 M [48],reas stellar-mass black holes found in binaries in ourxy have masses substantially greater than the compos of GW170817 [49–51].
ravitational-wave observations alone are able to meathe masses of the two objects and set a lower limit
heir compactness, but the results presented here do not
ude objects more compact than neutron stars such as
k stars, black holes or more exotic objects [52–56].
detection of GRB 170817A and subsequent electronetic emission demonstrates the presence of matter.
eover, although a neutron star–black hole system is not
d out, the consistency of the mass estimates with theamically measured masses of known neutron stars in
ries, and their inconsistency with the masses of known
k holes in galactic binary systems, suggests the sourcecomposed of two neutron stars.

2017 Aug 17

GW170817:
The ﬁrst detec4on of GWs
from a NS merger

DATAt the time of GW170817, the Advanced LIGO detecand LIGO
the Advanced
detector were in observing
Scien6ﬁcVirgo
Collabora6one. The maximum distances at which LIGO-Livingston
and Virgo Collabora6on, 2017, PRL
LIGO-Hanford could detect a BNS system (SNR = 8),
wn as the detector horizon [58–60], were 218 Mpc and

FIG. 1. Time-frequency representations [57] of data containing

The Astrophysical Journal Letters, 848:L13 (27pp), 2017 October 20

Abbott et al.

Gamma-rayFermi & INTEGRAL~2 sec aXer the merger

LIGO Scien6ﬁc Collabora6on
and Virgo Collabora6on, 2017, ApJ

Figure 2. Joint, multi-messenger detection of GW170817 and GRB170817A. Top: the summed GBM lightcurve for sodium iodide (NaI) detectors 1, 2, and 5 for
GRB170817A between 10 and 50 keV, matching the 100 ms time bins of the SPI-ACS data. The background estimate from Goldstein et al. (2016) is overlaid in red.
Second: the same as the top panel but in the 50–300 keV energy range. Third: the SPI-ACS lightcurve with the energy range starting approximately at 100 keV andwith a high energy limit of least 80 MeV. Bottom: the time-frequency map of GW170817 was obtained by coherently combining LIGO-Hanford and LIGO-Skymap from 3 detectors (LIGO x 2 + Virgo)==> 30 deg2 (~40 Mpc)
P
H
Y
S
I
C
A
L
R
E
V
I
E
W
PRL 119, 161101 (2017)
5°

30°

N
E

0°
15h
18h
-30°

12h
9h
-30°
0

25

50

Mpc

75

3. Collabora6on
Sky location
for GW170817
by a rapid
LIGOFIG.
Scien6ﬁcandreconstructed
Virgo Collabora6on,
2017

localization algorithm from a Hanford-Livingston (190 deg2 ,may beorbitaltime eva specm2 , theorbit srapidly
enced
q¼m
spin-sp
The
importthe bocompa
and acinduce(C) Michitaro Koike (NAOJ/HSC)

Electromagne4c counterpart of GW170817 @ 40 Mpc
J-GEM: Japanese collabora6on for Gravita6onal-wave
Electro-Magne6c follow-up (PI: Michitoshi Yoshida)

Subaru/HSC z +IRSF/SIRIUS H, Ks(Utsumi, MT et al. 2017, PASJ)arrow
Surveywith
Subaru/HSC
ationsrationgn ofwave
y withich is8.2m
ng themostr, we
ies ofct theall the

300o

30o

300o

30o

Fig. 1. Pointing
mapon the probability map
Tominaga,
MT foret al.GW170817
2018, PASJ inoverlaidpress, arXiv:1710.05865(LALInference v2.fits.gz;
Abbottet al. 2017c).
white contour represents
DECam:
Soares-Santos
et al.The
2017

Fig.Publications
7. Stacked andof
difference
z-band imagesSocietyof J-GEM17btc(a.k.a.(2014),
SSS17a/DLT17ck)
associatedwith NGC 4993 located in the 3D skymap of GW170817.
the Astronomicalof Japan,Vol. 00, No.
0
The archival HST ACS image is also shown. The lengths of ticks are 11 arcsec and the figure size is 56 × 56 arcsec2 .

Sources
GLADE catalog. We search for possibly associatedgalaxies in1551
the GLADE catalog or NED with a separation of < 2.0 arcsec for the 322 sources at the center of extended PS1 objects,
negative
positive
Positive detection
which is on
smallerthe 19criteria to identify
461 duplicate galaxies
1090
Aug than18 andin the GLADE catalog (3.6 arcsec), and with a separation of< 15.0 arcsec for the 62 off-center sources, which corresponds
extendednon-extended or no close object
Associated object
to a separationof <catalog
3 kpc at a distance
706of 40 Mpc. If the 3D
in PS1384
probability of GW170817 occurrence at the location and distance of the associated PS1 objectcenterwith aofHEALPix 3D grid
off-centerTransientlocation−3
with resolution of NSIDE=1024extended
is less than
10 of thetransient
maxiobject
in PS1 catalog
322
62
mum probability, the source is ruled out.
This screening reduces
the number of sources to 224 sources No
at the center of No
extendedin 3D
skymap sources.
information Inside
information
PS1Location
objects and
59 off-center
1
58
224
Visual inspection

58

1

Probability to beinside of 3D map
1Fig. 8. Stacked and difference z-band
images of an off-centercandidate J-5
=
9.3
x
10
GEM17bog. The archival PS1 i-band image is also shown. The lengths of

There is only one source (J-GEM17btc) associated with aticks are 2 arcsec andthe figure
sizeofis 20
× 20 arcsec2 . func4on)(Faintend
luminosity
Fig.
5. Flowchartof the candidate
screening
The number
PS1
objectthat is locatedin the 3D
skymap.process.
The detailof J- in eachbox represents
the numberof remaining
sources after
screening.
GEM17btc
is describedin thenext subsection.
On eachthe otherhand, the other 282 sources do not have distance measurement
3.2 Properties of candidates
in the GLADE catalog or NED. After the catalog matching, fourof artificial sources. The median of 5σ limiting magnitude
isinvestigate properties of remaining 60 candidates.
Weof the authors remove bogus and high proper motion stars byroughly comparable
to the 70%
Tominaga,
MTcompletenesset al. 2018,magnitude. Figure 7Fig.
6. Example
of sourcesby thePS1
visualinspectionshows
the candidate
with excluded
the associatedobjectvisual inspection (Figure 6). The number of final candidates,
motionand (bottom)
bogus detection
at thePASJ
inpress,include
arXiv:1710.05865
Asbe
therelated
detectedsources
many5).bogus
detection,
can- the proper
within3D skymap
of stars
GW170817.
J-GEM17btc
is locatedat cent
that may
to GW170817,
is
60 (Table
We notethat
tended objects. The lengths
are 2 arcsec and the◦ of′ ticks′′
selectionis performed
as of
done
in Utsumi
et al. (2017a).
R.A. = 13h 09m 48.s 07, decl.
=
−23
22
53.
4
(J2000.0),
which
58 didatecandidates
are locatedat the center
extendedPS1 objects
2

Remaining 59 objects(58 center, 1 oﬀset)

That of NGC4993= 0.6420 × 20 arcsec .

017

X-ray and radio@ ~10 daysb

N
GW170817
E

10–3
10–4

X-ray
(on-axis)

10–5

0.5–8.0 keV
26 August 2017

5″

6 GHz

19 GHzi band

10–6
10–7

ChandraOp4cal ﬂux

X-ray

15

Apparent AB magnitude

population of short GRBs at cosmological distances , and its physicalconnection with the gravitational-wave event remained unclear.
A vigorous observing campaign targeted the localization regionof the gravitational-wave transient, and rapidly identified a source ofbright optical, infrared and ultraviolet emission in the early-type galaxy
NGC 499316,17. This source was designated ‘SSS17a’ by the Swope
team16, but here we use the official IAU designation, AT 2017gfo.
AT 2017gfo was initially not visible at radio and X-ray wavelengths.
However, on 26 August 2017, we observed the field with the Chandra
X-ray Observatory and detected X-ray emission at the position
Tv ≈ 28º, Tj ≈ 15ºof AT 2017gfo (Fig. 1). The observed X-ray flux (see Methods)
implies–1
10
an isotropic luminosity of 9 × 1038 erg s−1 if located in NGC 4993
at a distance of about 40 Mpc. Further Chandra observations,–2
10theperformed between 1 and 2 September 2017, confirmed
presence

Flux density (mJy)

nt
ns
ve
at
ve
id
10
,
nt
ay
nt
ay
nd
he

20

25

30

10–8

in less than a quarter of short GRBs5. Dust lanes are visible in the inner
10
100
regions, suggestive of a past merger activity (see Methods). b, Chandra 1
observations revealed a faint X-ray source at the position of the optical/
Time since gravitational-wave trigger (days)
infrared transient. X-ray emission from the galaxy nucleus is also visible.

35

Figure 3 | Multi-wavelength light curves for the counterpart of
GW170817. a, Temporal evolution of the X-ray and radio counterparts

offbaseTroja+17

A. 2Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt,
liere 100, 00133 Rome, Italy. 4Department of Physics, University of Bath, Claverton Down, Bath6

Electromagne4c signature from compact binary merger(NS-NS or BH-NS)•

X-ray/gamma-ray

strophysical Journal, 746:48 (15pp), 2012 February 10

specific stellar populations). Because merger counterparts
redicted to be faint, obtaining a spectroscopic redshift
allenging (cf. Rowlinson et al. 2010), in which caseroscopy of the host galaxy is the most promising means
taining the event redshift.
s important to distinguish two general strategies for conng EM and GW events. One approach is to search for a
signal following an EM trigger, either in real time or at
t-processing stage (e.g., Finn et al. 1999; Mohanty et al.
). This is particularly promising for counterparts predicted
cur in temporal coincidence with the GW chirp, such as-duration gamma-ray bursts (SGRBs). Unfortunately, mostpromising counterparts (none of which have yet been
endently identified) occur hours to months after coales.6 Thus, the predicted arrival time of the GW signal willn uncertain, in which case the additional sensitivity gained
this information is significantly reduced. For instance, if
me of merger is known only to within an uncertainty ofurs (weeks), as we will show is the case for optical (radio)
erparts, then the number of trial GW templates that mustarched is larger by a factor ∼104 –106 than if the merger
is known to within seconds, as in the case of SGRBs.
second approach, which is the primary focus of this paper,
M follow-up of GW triggers. A potential advantage in thisis that counterpart searches are restricted to the nearby

Short GRB: strongly beamed• Radio- Delayed by years- Emission from jet
can come earlier

Metzger & Berger

Jet ISM Shock (Afterglow)
Optical (hours days)
Radio (weeks years)

Ejecta ISM ShockRadio (years)

GRB

obs

(t ~ 0.1 1 s)

Kilonova

Optical (t ~ 1 day)j

Merger Ejecta
Tidal Tail & Disk Windv ~ 0.1 0.3 c

BH• Op4cal/NIR

Delayed by only ~ 1 week
Isotropic

Figure 1. SummaryMetzgerof potential&electromagnetic
counterpartsof NS–NS/
Berger 2012,
ApJ 746,
48
NS–BH mergers discussed in this paper, as a function of the observer angle
θobs . Following the merger a centrifugally supported disk (blue) remains aroundthe central compact object (usually a BH). Rapid accretion lasting !1 s
powers a collimated relativistic jet, which produces a short-duration gammaSummary of mul4-messenger observa4ons

Abboc+17

The Astrophysical Journal Letters, 848:L12 (59pp), 2017 October 20

GW

γ-raysVery weak=> oﬀ-axis??

GRB
X-ray
Blue kilonova
Red kilonova
Radio

Abb

What we learn from mul4-messenger astronomy• Hubble constant• GW => luminosity distance, EM => redshif• H = 70 km s Mpc
0

+12-8

-1

-1

• Speed of GW• Gamma-rays arrived 1.7 s afer the merger(afer 130 M light year race => 4 x 1015 s)• Physics of neutron star

• R ~< 14 km (for 1.4 Msun NS)• Jet forma4on/propaga4on in the merger• ~2 sec?

• Origin of heavy elements

GW170817: Op4cal/infrared Observa4ons and Kilonovae• GW170817: mul6-messenger observa6ons• Kilonova and the origin of heavy elements• Future prospects

Mass ejec4on from NS merger
Top view- Tidal disrup4on- Shock hea4ng

Side viewM ~ 10-3 - 10-2 Msunv ~ 0.1 - 0.2 c

Sekiguchi+15, 16

r-process nucleosynthesis in NS merger

Korobkin+12

ng ofinedo
pholatterd fisnucleimanns: thed theinsky). For
duced
rates
from

Radioac4ve
energy=>op4calemissionTransients from compact object mergers

NS
m

erg
er

1
t-1.3

2653

10 100days

Supernova

Metzger+10, MNRAS, 406, 2650

Figure 1. Radioactive heating rate per unit mass Ė in NS merger ejecta

L“Kilonova/Macronova"

Lpeak

Ini4al works: Li & Paczynski 98, Kulkarni 05, Metzger+10, Goriely+11, …
High opacity: Kasen+13, Barnes & Kasen 13, MT & Hotokezaka 13, …

tpeak
Timescale

tpeak

3 Mej
4 cv

=

8.4 days

Luminosity*assuming 50%
thermaliza4on

Lpeak

=

1/2

t

bound-bound transi4onsof heavy elements

Mej
0.01M

1/2

v
0.1c

1/2

1/2

10 cm2 g 1

Ldep (tpeak )1.31040 erg s 1

Mej
0.01M

0.35

v
0.1c

0.65

0.65

10 cm2 g 1

Light curves of kilonova

MT & Hotokezaka 13, MT+14,

-16

NIR

L ~ 1040-1041 erg s-1
t ~ weeks
NIR > Op4cal

Absolute magnitude

-15
-14
-13
-12
-11
-10
-9

Model: MT+17a

g
r
i
z
J
H
K

Op4cal0

510Days after the merger

15

5

open s shell
(l=1)

4

open p-shell(l=2)

E (eV)

3

open d-shell
(l=3)

5

E (eV)

3

2

0

open f shell
(l=4)

1

0

4

1

2

Nd II

Fe II

GW170817: light curves- Brightness- Timescale
- SED

NIR

Observed magnitude

17

Model: MT+17b
Data: Utsumi, MT+17, Drout+17,
Pian+17, Arcavi+17, Evans+17,
Smarc+17, Diaz+17, Valen6+17,
Cowperthwaite+17, Tanvir+17,
Troja+17, Kasliwal+17

18

g
r
i
z
J
H
K

-17

-16

-15

19

-14

20

-13

21

22

Op4cal0

510Days after GW170817

Clear signature of lanthanide produc4on!!
Ejecta mass ~0.03 Msun

-12

-11
15

Absolute magnitude

16

GW170817: Spectra- Smooth spectra
Smoking gun!!

Spectra taken w/
VLT/X-shooter
Data: Pian+2017
Model: MT+2017

np
ne
=
Ye =
np + nn
np + nnνe + n -> p + en + e+ -> νe + p

higher T
higher Yeν- Low Ye => stronger r-process- Neutrino absorp4on increases Ye
d

p

s

f

Se

100

Ru

Te

Ye = 0.30

NdEr

Ye = 0.25

Ye = 0.10-0.40

Mass fraction

10-1
10-2
10-3
10-4
10-5

30

40

50

60
70
Atomic number

80

90

100

Presence of “blue” kilonova
Cowperthwaite et al. 2017;
Drout et al. 2017; Nicholl et al. 2017;
Villar et al. 2017=> wide range of r-process elements
Ye = 0.25
Ye = 0.1

MT+2017

S Rosswog et alClass. Quantum Grav. 34 (2017) 104001

GW
Kilonova

Rosswog+17
Hotokezaka+15, 18

SN rateFigure 2. Summary of various rate constraints. The lines from the upper left to lower

CAVEATS:notwell constrained
right indicate theabundance
typical ejecta massra4os
required toare
explainall r-process/all
r-process with

ら れ る． こ の 加 −熱はr-process nucleosynthesis in core-collapse
supernovae
νe＋
n→p＋e
ニュートリノ（νe）捕獲

Wanajo, Janka, & Mül5Ye, min = 0.466

The Astrophysical Journal Letters, 726:L15 (4pp), 2011 January 10

1D 2D

および陽子（p）の反電−νe＋n→p＋e
Ye, min = 0.404

mass [10-3 solar]

4
3
2

＋

ν̄ e＋p→n＋e
および陽子（p）の反電
1

0
0.40

0.45

Ye

0.50

0.55

Figure 2. Ejecta masses vs. Ye for the 1D (blue) and 2D (red) explosion mod
The width of a Ye -bin is chosen to be ∆Ye = 0.005. The minimum values oare indicated for both cases.
(A color version of this figure is available in the online journal.)

expands continuously, and a neutrino-powered explosion sets in
at t ∼ 100 ms p.b. in 1D and 2D essentially in the same way
and with a very similar energy (∼1050 erg; Janka et al. 2008).
In the multi-dimensional case, however, the negative entropyn relative to solarによるものである．超
＋
ν̄
＋
p
→
n
＋
e
e
Diﬃcult to produce r-process elements in
により，この二つの反
normal (neutrino-driven)core-collapse supernova

Figure 1. Snapshot of the convective region of the 2D simulation of an ECSN
at
262 ms after coreWanajo
bounce with
Wanajo+11,
14entropy per nucleon (s; left) and Ye (right).
Mushroom-shaped lumps of low-Ye matter are ejected during the early phase of
the explosion.
(A color version of this figure is available in the online journal.)

104
3

10

102

Ca

Cr
Ni
Ge
Kr
Zr
Ti
Fe
Zn
Se
Sr
Mo
1D 2D

* r-process in peculiar SNe is NOT excluded
101 (e.g., magne4c ﬁeld)0Origin of r-process elements
Supernova

M. Weiss

Well known event rate

Diﬃcult to have r-process?

NS merger

NASA

Robust r-process
Unknown event rateand ejec4on per event

GW170817: Op4cal/infrared Observa4ons and Kilonovae• GW170817: mul6-messenger observa6ons• Kilonova and the origin of heavy elements• Future prospects

40 Mpc
g
r
i
z
J
H
K

17

Observed magnitude

18
19
20

-16
-15
-14
-13

1m
op4cal

21

-12

22

-11
2m
(PS1 3pi, z-band)

23
24
25

-17

-10
-9

8m
(1 min, z-band)

0

5

10

Days after GW170817-8
15

Absolute magnitude16

100 Mpc
g
r
i
z
J
H
K

17

Observed magnitude

18
19
20

-18
-17
-16
-15

1m
op4cal

21

-14

22

-13
2m
(PS1 3pi, z-band)

23
24
25

-19

-12
-11

8m
(1 min, z-band)

0

5

10

Days after GW170817-10
15

Absolute magnitude

16

Many open ques4ons• Origin of ejecta?
• Origin of “blue” and “red” component?
• Blue component with high veloci6es?
• Abundance pazern? Similar to solar abundances??
• 3rd peak?? (Au and Pt!)

ol. 00, No. 0

5High Ye
Medium Ye

Low YeFig. 4. Schematic picture of the ejecta of the NS merger event GW170817.

Relative log

352-AA46-08

–4
ARI

–6

15 July 2008

11:46

“Universality” of r-process abundances
–8
–10

a

0
–12

b

log

Relative loglog

2
1
–4
0
–6
–1

Individual stellar abundance offsets with respect to Simmerer et al. (2004)

–8
1

c

–10
0

Solar ra4os

–12
–1
130

Average abundance offsets with respect to Arlandini et al. (1999) ‘‘stellar model’’

40

50

60

70

80

90 b

log

Atomic number0–1

CS 22892-052: Sneden et al. (2003)
HD 115444: Westin et al. (2000)
BD+17°324817: Cowan et al. (2002)

Sneden+2008
Individual stellar abundance offsets with respect to Simmerer et al. (2004)

open s shell(l=1)

Kasen+13: Sn II, Ce II-III, Nd I-IV, Os II
Fontes+17: Ce I-IV, Nd I-IV, Sm I-IV, U I-IV
Wollaeger+17: Se, Br, Zr, Pd, Te
MT+17: Se I-III, Ru I-III, Te I-III, Nd I-III, Er I-III

open p-shell(l=2)

Kasen+17: all lanthanides
open d-shell(l=3)
1st peak
2nd peak
3rd peakopen f shell(l=4)

3d , 3d 4s, 3d 4p, 3d 4d, 3d 4f, 3d 5s, 3d 5p, 3d 6s, 3d 4s4p, 3d 4s
4f 4 6s2 , 4f 3 5d6s 2 , 4f 4 5d6s, 4f 4 5d 2 , 4f 3 5d6s6p, 4f 4 5d6p
4f 4 6s, 4f 4 5d, 4f 4 6p, 4f 3 5d 2 , 4f 3 5d6s, 4f 3 5d6p, 4f 3 6s6p
4f 4 , 4f 3 5d, 4f 3 6s, 4f 3 6p, 4f 2 5d 2 , 4f 2 5d6s, 4f 5d 2 6s
4f 3 , 4f 2 5d, 4f 2 6s, 4f 2 6p
4f5d2 , 4f 5d6s, 4f 2 6s, 4f 2 5d, 4f 6s 2 , 4f 5d6p, 4f 2 6p, 5d 3 , 4f 6s6p, 4f 3
4f5d, 4f 6s, 5d 2 , 4f 6p, 5d6s
5d6 6s, 5d 6 5f, 5d 6 5g, 5d 6 6s, 5d 6 6p, 5d 6 6d, 5d 6 6f, 5d 6 6g
5s2 5p, 5s 2 4f, 5s 2 5d, 5s 2 6s, 5s 2 6p, 5s5p 2 , 5s5p6s, 5s5p6p

Ni iv
Nd i
Nd ii
Nd iii
Nd iv
Ce ii
Ce iii
Os ii
Sn ii

Energy levels of Nd II

Notes.
a Electron configurations used in the auto structure calculations. Ground states (from NIST) areb Ionization potential, taken from NIST.

10
Nd II

8

HULLACGRASP Layer 0
GRASP Layer 1

Energy (eV)

6
4

4
2

0

0
4

20
Nd III
15

10

4

4f 5d

3

2

4f 5d

MT+17

HULLACGRASP Layer 0
GRASP Layer 1
GRASP Layer 23

4f 5d6s

4

4f 6p

3

4f 5d6p

HULLACGRASP Layer 0

6

2

4f 6s

Energy (eV)

Er II

3

12

4f 6s6p

4f 6s

11

2

4f 6s

11

11

4f 5d6s 4f 5d

2

12

4f 5d

12

4f 6p

11

11

4f 6s6p 4f 5d6p

Figure 2. Atomic structure model calculations of the excitation energy of thelowest 10
level of Nd ii electron configurations. The circles denote the results from
Autostructure obtained under various optimization approaches (described in
the text). The stars
Erdenote
III the experimental energies from NIST.
(A color version of this figure is available in the online journal.)

Kasen+13 (Autostructure code)
8

HULLACGRASP Layer 1

case the mean line opacity may be less sensitive to the exact
configuration
ordering.
6
We considered a second strategy (opt2) whereby the above
optimization was first applied to only those orbitals includedin the 4ground configuration. These scaling parameters werethen fixed, and a second optimization was carried out varying
the parameters of all remaining orbitals. This method usually

Not very accurate for transi4on wavelengths
Energy (eV)Energy (eV)8Theadjustinfor Ndcalculareproduexactly
but thisof an arNd ii, w
curve c

10

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known
In partincludi(∼42 mdominastructuwhich
observeSN mo
the opt
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the obsmodelsSummary
GW170817 and kilonova•• Red and blue components=> Ye ~ 0.25 or X(Lan) ~ 10-3-10-2 if single component• ~0.03 Msun ejec6on with Lanthanide=> Enough to explain the origin of r-process elements• Open ques4ons• Mechanism of high mass ejec6on• Abundance pacerns (solar parcern?)• Future prospects

events with diﬀerent masses, mass ra6os,• Moreand viewing angles• Systema6c construc6on of atomic data