EM Observations in theMulti-messenger
Astronomy Era
Nobuyui Kawai
Tokyo TechNon-EM Messengers• Gravitational Waves• High frequency (>1 Hz)• Low frequency (<1 Hz)• Neutrinos• Very High energy• Nuclear energy (~MeV)• Low energy• Cosmic Rays
• Nucleons• Electrons• Exotic Particles• WIMPs• Magnetic monopoles

Non-EM Observatories
Facilities

When

Localization

High freq GW

LIGO, Virgo, KagraNow

 ~10 deg

Low freq. GW

LISA, Decigo

>2030

?

HE neutrino

IceCube, ANTARESNow

 ~degNucl. neutrino

SuperKamiokandeNow ~10 deg

LE neutrino

?

?

?

CR Nucleon

Auger, TANow

 ~10 deg

CR Electron

CALET, Fermi

Now ~10 deg

WIMP

Xenon100, XMASS,
etc.

?



Monopole?

?

Non-EM Sources
Galactic

Local Universe

CosmologicalHigh freq GWSupernova

Compact Merger

Low freq. GW

Binary stars

BH binary

BH binary

HE neutrino

BH/NS with jets?

SMBH with jets?

GRB?

Nucl. neutrino

Supernova

LE neutrino

?

?

?

CR Nucleon

Supernova remnant,
BH/NS with jets?

Now

CR Electron

Supernova Remnant,pulsars, BH/NS jets?

Now

WIMP

?

?

primordial

Monopole?

?

primordialnon-EM astrophysical sources• Local (<10’s of Mpc) or
Galactic• Rare and unpredictable• Poor or moderate
localization• High-energy• in low-z galaxy,maybe absorbed if
Galatic• long+high duty-cycle+ large sky coverage• Wide-field required forfollow-up• UV/X-/gamma-ray,
all EM (non-thermal)EM search consideration #1• Local (<10’s of Mpc) or
Galactic• Small aperture may be okayèin low-z galaxy,maybe absorbed• Sensitive search (e.g.
Subaru HSC) must be clever• e.g. ASAS-SN• spectroscopic follow-up
difficult for too many fainttransient sources• Huge data
• need association with rare
events• X-ray or radio source,• timing coincidence• Radio, IR, X-/gamma-ray
useful for GalacticEM search consideration #2• Rare and unpredictableèlong+high duty-cycle+ large sky coverage• ground-based orsatellite with long (>years)
mission life
• Tiling has limitations• Facilities with large sky
coverage• LF radio: LOFAR etc• HF radio:• IR:• Optical: ASAS-SN, Evry, Pi of
Sky, ...
• UV:• Soft X-ray:• Hard X-ray: Swift BAT• LE gamma-ray: Fermi GBM• HE gamma-ray: Fermi LAT• VHE gamma-ray:

EM search consideration #3• Poor or moderate
localizationèWide-field required forfollow-up• Facilities• exsist? available?

• wavelength coverage• Sensitivity vs. field size
• target to galaxies?

• latency• Human in the loop
• Tiling• Identification• Time variability – need
repeated observation• Spectroscopy• Sensitivity• too many?

EM search consideration #4• High-energy
èUV/X-/gamma-ray,
all EM (non-thermal)• Facilities with large sky
coverage• LF radio: LOFAR etc• HF radio:• IR:• Optical: ASAS-SN, Evry, Pi
of Sky, ...
• UV:• Soft X-ray:• Hard X-ray: Swift BAT• LE gamma-ray: Fermi GBM• HE gamma-ray: Fermi LAT• VHE gamma-ray:

Soft X-ray mission

Flux (erg/s/cm^2)

MAXI on
GW150914

10

-4

10

-5

10

-6

10

-7

10

-8

10

-9

10

-10

10

-11

10

-12

10

-13

10

-14

10

-15

10

-2

10

-1

10

0

10

1

10

2

10

3

Time since Trigger (sec)

10

4

10

5

10

6

GW150914-GBM
a shortGRB,
a moreenergy
favorableenergy is unnecessary because a likelihood-based statistic correctly
accounts for islow
count
ratesthenin withindividual
arrivaldirection,
it
would
have
causedanonboard
trigger.
correctly accounts for low count rates in individual energy channels. In practice, the implementation of CSTAT in our If
GW150914-GBM
part of theshort GRBﬂuctuations
population,asthen
channels. In practice, the implementation of CSTAT in our spectral
ﬁtting softwareis neglects
backgrounda its
ﬂuenceis not atypicalbut its unfortunate
arrivalrates
direction
spectral ﬁtting software neglects background ﬂuctuations as a separate
contribution
to the uncertainty
in the total countinyields data,
onlyana weaksignalin
GBM.
Figure5showsthat theseparate contribution to the uncertainty in the total count rates in the GBM
effect that is mitigated by rebinning the data
is a Areasonable
ﬁt toofthe
spectrumeven atis low
the GBM data, an effect that is mitigated by rebinning the data priormodel
to ﬁtting.
consequence
thiscount
limitationof CSTAT
implyingnopaucityofcountsat
lowenergiesin NaIprior to ﬁtting. A consequence of this limitation of CSTAT is that energies,
the uncertainties on the parameters returned by the ﬁts are5, which
is
the
only
detector
with
a
small
enoughviewing
angle
that the uncertainties on the parameters returned by the ﬁts are almost
certainly underestimated. In the analysis that follows, weto 68%
the source
position
to
have
any
sensitivity
below
50
keV.
almost certainly underestimated. In the analysis that follows, we reportstatistical uncertainties,
with the caveat that the true+160
At a aredistanceof 410report 68% statistical uncertainties, with the caveat that the true uncertainties-180 Mpc
probably
higher.
GRB implied
spectra by
are thewellGWobservations(Abbottetal.
2016b),
we
obtainasourceuncertainties are probably higher. GRB spectra are well represented
by empiricalfunctionspower-law components+1.5
49 with −1
1.8
´
10
erg
s
in
the
1
keV–10luminosityofrepresented by empirical functions with power-law components around
1.0
a peak energy in the spectral energy distribution, E peakMeV.
Figure 4. The LIGO localization map (top left)
canabecombinedthe GBM
localization
mapE peakfor. GW150914-GBM(top isright)
assuming
GW150914-GBM
isenergyrange thatfor reporting
suchbolometricaroundpeakenergy inwith
the spectralenergydistribution,
The Band function
is usedstandard
when there
are enoughcountsto
The AstrophysicalJournalLetters,
826:L6(19pp),
2016
July with
20 theConnaughton
al.
associatedwith GW150914.
The combined
map
isBandshown(bottomskyareregionthatcounts
is occulted
toluminosities.
Fermi
the bottomthe
right
plot.
constraint
The inuncertainties
reﬂectthe Therange
of etpossibleThefunctionis left)
used
when
there
enoughto constrain
all removed
parameters,
particularly
high-energy
power-law
distancestotheprogenitor,
uncertainties
inthespectralfrom Fermi shrinks the 90% conﬁdence region
for theallLIGO
localization
fromthe601
to 199 square
degrees.
constrain
parameters,
particularly
high-energy
power-lawindex, β. If β is not constrained, a power-law ﬁt with an ﬁtparameters(usingtheEpower-lawﬁts), and the range of arrivalindex, β. If β is not constrained, a power-law ﬁt with an exponential
cut-off
above
peak , called the Comptonized model,
directions
along
the
arc.
This
luminosity
is Ean orderof
exponential cut-off above E peak , called the Comptonized model, generally works well. For the weakest bursts,
or whenpeak lies
magnitude
dimmer
than
the
peak
luminositiesofthedimmestgenerally
worksNaI
well.detectors
For the weakest
equal count rates are expected in mostof theif bursts, or when Epeak lies outside the energy range of the instrument, a power-law ﬁt is
short and
GRBs
in to
theprovide
sampleananalyzed
by theWanderman
outsidetheenergyrange
oftheinstrument,a power-law ﬁt is adequate
servesestimate ofﬂux and &the event is bright enough.
Piran(2015).
adequate and serves to provide an estimate of the ﬂux and ﬂuence of the burst as long as the energy range over which theWe ﬁnd that the localization ﬂuenceof GW150914-GBMof the burst as long as theisenergy range over which the ﬂux and ﬂuence are calculated is not extended outside theconsistent with part of the LIGO localization
annulus.
If theﬂux and ﬂuence
are calculated
is not extended outside the observation range.
3.3. Other
Observations
GW150914-GBM
We ﬁndthat for allof 11
positions along theobservation
We ﬁnd thatfor all 11 positions along the LIGO arc, a power-law ﬁt to the data from GW150914-GBM
transient event uncovered in the GBM
data isrange.
associatedwithother than GBM can also detect impulsive
LIGO arc, a power-law ﬁt to the data from GW150914-GBM can be Instruments
constrained. For one of the positions, we can also provide
GW150914, then the GBM probability
map
can
be
combined
eventsinthehardenergy range. No pointed instruments
can be constrained. For one of the positions, we can also provide weak constraints for a X-ray
ﬁt to the Comptonized model. Figure 5
reported
observations
of
GW150914,
that they werewith the LIGO annulus to shrink the90%
conﬁdencelevel
weak constraints for a ﬁt to the Comptonized model. Figure 5 shows a representative count spectrum andsuggesting
power-law model ﬁt
notlooking
inthat
direction
at
the
time
of
the
GW
event.
a representative
LIGO localization by 2/3, as shownshowsin Figure
4. count spectrum and power-law model ﬁt to the Upper
data from 0.384 to 1.408 s relative to the time oflimitstotheemission
from
GW150914
fromnonto the data from 0.384 to 1.408 s relative to the time of GW150914, with a deconvolution assuming the source lies thenear
detectionby
instruments
on
board
the
Astrorivelatore
Gamma
GW150914, with a deconvolution assuming the source lies near the central position of the southern arc. For each of the 11 a
Immagini Leggero (AGILE) close in time to the GW event are
3.2. Energy Spectrum of GW150914-GBM
the central position of the southern arc. For each of the 11 positions
along the arc, we ﬁnd the best-ﬁt power-law index andreported by Tavani et al. (2016). The MicroCalorimeter had
positions along the arc, we ﬁnd the best-ﬁt power-law index and associatedamplitude. We use these parameters to simulate each
non-optimal
exposure to the GW event, from which upper
The data for GW150914-GBM imply
a weakbut Wesigniﬁcantassociatedamplitude.
use these parameters to simulate each spectrum
104 times, using the resulting distribution to estimate
limitsto
GW150914-GBM
calculated that are compatible4
spectrum10 times,
using
resulting distribution to estimate the uncertainties on the parameterare
values
(68% conﬁdence
level).
hard X-ray source with a spectrum that
extends
into
thetheMeV
with
the
GBM
ﬂuence.
The
other
instruments
on board
AGILE
the uncertainties on the parameter values (68% conﬁdence level). We also sample the parameter distributions
tocalculatetherange and a location that is consistentwithanarrivaldirectionobserved
most
of
the
LIGO
annulushundreds
ofseconds
We also sample the parameter distributions to calculate the ﬂuence and its conﬁdence region, weighting the sampling along oneither side of the GW event, but not at the time of the event.
along the southern lobe of the sky
map
GW150914.
ﬂuenceand itsfor
conﬁdence
region, weighting the sampling along the arc according to the LIGO localization probability contained
The anti-coincidence shield (ACS) of the Spectrometer on
arc GBMaccordingdetectors
to the LIGO to
localization
probability
Converting the observed counts inthethe
a
near
each
point
the arc.
Wetoobtain
best-ﬁt
power-law
index
Figure 5.containedPower-lawﬁtboardto thedataonfrom
0.384
1.408
s relative
to thearea
timeofa alarge
collection
above
−1
−2
−1
+
0.18 INTEGRAL (SPI) has+0.002
near
each
point
on
the
arc.
We
obtainabest-ﬁt
power-law
index
1.40
0.002
and
amplitude
photonss
cm
keV
GW150914,
from NaI 80
5-keV(blue)
andanBGO(red),
corresponding
to thebyhigh
0.24 with-0.001source ﬂux requires a deconvolution +0.18
of the instrumental
all-sky0 responsethat is not hinderedEarth−2+0.002-1.40-0.24
0.002
and
amplitude
s−1bincminkeV−1 7.overthe
LIGO
localizationarc,
yieldingaﬂuencebetween10-0.001 photons
time
FigureThesymbols
show
the
data.
The
solid
line
shows
the
bestFigure
2.
Model-dependent
count
rates
detectedasafunctionoftimerelativeoccultation (von +Kienlin
et-7al. 2003).
response with an assumed spectral model.
Wesamplearange−2We looked for a signal in
1.7
localizationarc, yielding
between model.
10 and 1000
2.4timekeV atofon
erg
cm show.
ﬁt Figurepower-law
Residuals
thebottompanel
scatterbut
no-1.0 ´to the start of GW150914-GBM, ∼0.4 s overafterthetheLIGO
GW event.
count a ﬂuence
the
of 10
GW150914-GBM
and
found
no excess3. DistributionSPI-ACSof transients
identiﬁedby thetargeted search
pipeline
in+1.7The raw-arc,
7 erg cm−2.
of arrival
directions
along
the
observed
LIGO
location
2.4
´
10
and
1000
keV
of
30 assumingForadeconvolutionasourcepositionatthe
1.0
systematicdeviation.
We
cannot
use
the
ﬁrst
and
last
energychannelsineitherrates are weighted and summed to maximize the signal to noise for a modeled
The SPI-ACS
teamreporteda0.256
ﬂuenceabove
background.
±120
ks
of
GBM
data
surrounding
GW150914.
The
eventsarebetweendeconvolution
positionthe (there−2
northeastern
tip ´
of 10
the-7southernlobe(entry10
in TableMeV
2), theusing
the data
andtimeassociatedresponses
foragreenthedetectors
atdetector
dataatstype
areandelectronic
overﬂow
events),source.
CTIME
bins are 0.256
s wide. For
Thedata pointsassuming
areeachused ain source
1.3
erg cmin the100ThekeV–100
limit
and
8.192
in
duration
andofthresholdsortedby effects
best-ﬁtspectraltype.
dotted blueline
+energy
2.3
northeastern
tip
of
the
southernlobe(entry
10
in
Table
2),
the
E
3.5
of
Comptonizedmodel
converges
toﬁndabest-ﬁt
peak-1.1
the background
ﬁt. Thegold points
are the counts
in the timethat shows
range
based
on
a
null
detection
over
a
1
s
period(Ferrigno
leaving
the
data
from
12
energychannels
includedintheﬁt.
locationthat aremostfavorablyoriented
to period
the arrival
marks
the
likelihood
ratio
assignedtonearbycandidate
GW150914-GBM,
+2.3
+
0.57
E peak of 3.5-1.1 MeVet with
Comptonizedmodel
converges
to ﬁndE peak ofdata-0.16
a curve
power-law
index
, in
al. blue2015).
Furtheranalysisofbelow
the represents
SPI-ACS
issinglereportedsigniﬁcantemission,
the gray points
are outside
this
time
andmostthebluea best-ﬁtwhile-0.50onthe long-tailin the(hard
spectrum)thedirection.
Table
2 suggeststhat NaI
5 andwith
BGO
0period,
are the
+0.57
E
0.16
MeV
a
power-law
index
below
of
,
although
this
ﬁt
is
not
statistically
preferredoverthepower-law
peak board triggeredal. (2016).
estimatea source
signalbetween-0.50 GRBSavchenko
point shows the 1.024 s average over the gold points. For a single spectrum andin thegiven
dataetsample.
TheTheygreen
and gold
curvesshow
thedatatheforanymodel,
theinstrumental
response.
The
suitable
detector set for all of the locations
along
the
arc.
We
althoughthisﬁt weighted
is notstatistically
preferredoverpower-lawﬁt.
Whensimulating
iterations
of
the
burst
to
obtain
68%
5
and
15σ
above
backgroundshould
have
been
seen
in
the SPIsky location, detector counts for each energy
channelareaccordingtocandidates that favor the other template spectra used in the search.
28
ﬁt. duesimulatingof the burst
to obtain 68% routine
minimization
the were
best-ﬁtparameters
conﬁdencelevel
uncertainties
on represented
the parameters,
the Comptonizedﬁtusesfaileda,Whenwhichtakes aiterations
forwarduse thethemodeled
rmﬁt spectral
ﬁttingnoise
package
ACSproducing
data
if thesourceby therate and inverse
variance
to background.
Theweighted
conﬁdencelevel
uncertainties
onthe ﬁt failed about
50% ofthe time.
The
between
10 and 1000
spectrumfound
in aCSTAT.
ﬁt toﬂuence
the GBMdata assuming
one keVpositioncountsapproachfrom all NaI
BGO detectors
then summed
toobtainfolding
toand
determine
the areparametersthatbest aﬁtsignal-tothethe parameters,
likelihood-basedﬁttingstatistic,

Possible detection of gamma-ray
emission by Fermi GBM

Connaughton et al. 2016

arrival di
GW1509ﬂuence iyields onmodel isenergies,
5, which ito the sou
At aobservatio
luminosit
energy raluminosit
distancesparameter
directions
magnitudshort GR
Piran (203Instrum
events inreported o
not lookin
Upperdetection
Immagini
reported
non-optim
limits towith the G
observed
either sid
The anboard IN
80 keV w
occultatio
SPI-ACS
above ba
limit of 1
range bas
et al. 201
Savchenk
5 and 15σ
ACS data
spectrumon the L

MAXI could havemarginallydetected GBM
SGRB if it was in
the field of view

Flux (erg/s/cm^2)

MAXI on
GW150914

10

-4

10

-5

10

-6

10

-7

10

-8

10

-9

10

-10

10

-11

10

-12

10

-13

10

-14

10

-15

10

▲

-2

10

Fermi GBM possible detection(extrapolated to 2–20 keV flux
averaged over 1 second
assuming photon index –1.4)

-1

10

0

10

1

10

2

10

3

Time since Trigger (sec)

10

4

10

5

10

6

Short GRB 050709
The only short GRB observed in soft X-ray

HETE-2 Villasenor et al. 2005

HST

Fox et al. 2005

Short
hard
pulse

HETE-2
2–25 keV

Chandra“Soft extended emission”

z=0.160
Dwarf irregular galaxy
SFR = 0.2 Msun/yr

MAXI could
easily detect“short pulse” and“soft extended
emission” of
GRB 050709

Flux (erg/s/cm^2)

MAXI
sensitivity for
SGRB in
GW range

10

-4

10

-5

10

-6

10

-7

10

-8

10

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10

-10

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10

GRB 050709
Short pulse
GRB 050709
Extendedemission▲●

GRB 050709
Afterglow●(Chandra)
-2

10

-1

10

0

10

1

10

2

10

3

Time since Trigger (sec)

10

4

10

5

10

6

“Soft extended
emission” or X-ray
afterglow of a short
GRB at O2 BNS
range may be
detected by MAXIin the following
scan

Flux (erg/s/cm^2)

MAXI
sensitivity for
SGRB in
GW range

10

-4

▲

10

-5

10

-6

10

-7

10

-8

10

-9

10

-10

10

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10

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10

-13

10

-14

10

-15

10

GRB 050709 scaled to 100 Mpc
●

●

-2

10

-1

10

0

10

1

10

2

10

3

Time since Trigger (sec)

10

4

10

5

10

6

Short soft X-tray transients
Tidal disruption

Supernova /GRB
shock breakout

Merging neutronstar binary

è short GRBs
associated with
GW events

Supergiant fast
X-ray transientOr, priviously unknown
soft X-ray transients17X-ray transients: L-∆t
52

–1

0

Log luminosity (erg/s)

50

1

2

4

5

Long GRB
Short
GRB

48

Low
luminosity
GRB

M
A
X SN shock
I breakout Tidal Disruption

WF-MAXI
MAXI

46
44
42
40
38

3

log seconds
6
7

X-ray Burst
–6

–5

–4

–3

Nova
ignition–2–1

BH Binary
0

1

2
18
log days

の視野をカバーするように配置されており、広いエネルギー帯域での観測が可能となる。
バス部として、オンボード主計算機 (DP)、電源制御ユニット (PDU)、スターセンサー (ASC)
部 (Cooler driver) は、図 14 のように配置を検討している。 N. Kawai + WF-MAXI Team

“Wide-Field MAXI” on ISS

Advanced (or Autonomous) Stellar Compass、星姿勢計

HXM: Hard X-ray Monitor

“Wide-Field MAXI” on ISS

N. Kawai + WF-MAXI Team

Directionof MotionMAXI

JEM EF

goals••

Counterparts for GW sources (adv. LIGO/VIRGO, KAGRA)First large-sky monitor for short soft X-ray transientsfield of view

≈ 20% of the sky (covers 80% sky in 92 min)Instruments

Soft X-ray Large Solid Angle Camera (SLC: 0.7–10 keV)
Hard X-ray Monitor (HXM: 20 keV–1 MeV)

sensitivity

50 mCrab /30 s (SLC)

pos. accuracy

0.1

platform

ISS/JEM (Selection in 2014, operation 2018–)20

開始はこれよりも確実に（１年以上）遅れることを考えると，この制約条件を満たすことは全く保証されない．第３の目的は付加的なものであWF-MAXI evaluation

る．第４の目的については LB C9D1 との比較検討が必要である．

•)

このミッションを実施するのであれば，その規模（リスク経費を含まず

Application for ISAS Small Project (Feb 2014)に約億の見積もり）から考えて， 1G1 のミッションとして実施するこà Not selected
by Advisory committee for Space Scienceとが適切である．

エキストラサクセスとされている最大の目的が達成されれば，その科学• Extra-success (GW counterpart) has high science valueと稼働率,を• 的な価値は高い．しかし，天空をカバーする領域
Sky coverage 20% x Observing efficieny 50% à)10 %coverage• 考慮すると重力波の対応天体を発見する確率はあまり高くなく，リスク
Chance of finding GW counterpart is low; high risk
• は大きい．地上の観測網のみでフォローアップする場合との費用対効果
should compare the chance/cost with that by ground observation
aloneをよく検討すべきである．
• 高エネルギー宇宙物理のコミュニティは将来計画の策定作業中であり，
Future plan of the High Energy Astrophysics community is yet to
位置づけは不明である．一方，重力波天体は宇宙線分野の最重要な研究
be decided, and the position of this project is unclear.
• 対象の一つと認識されていることから，対応天体の検出確率を高めて，
However, GW has high priority in Cosmic Ray community.
• 宇宙線分野のミッションとして再定義することを検討するほうがよいか
Therefore it may be better to re-define it as a Cosmic Ray
mission
もしれない．

,-, 億と予想）に対して，• 評価委員会は，コスト（リスク経費を含めるとSelection committee considers the science output
is notサイエンスのアウトプットは十分ではないと判断し，提案チームに対し
sufficient to justify its total cost (5 bn JPY) , and asked the
proposer to find a way to reduce the costてコスト削減の検討を依頼した．その結果，コストを下げると，エキス• トラサクセスを達成する確率が更に小さくなることが明らかになった．
Cost reduction results in less probability to achieve the extrasuccess.
以降 (

まで

21

“iSEEP” Wide-Field MAXI

Proposed Feb 2015

Directionof MotionMAXI

JEM EF

goals

Localization/notification of X-ray transientsfield of view

≈ 10% of the sky (covers 80% sky in 92 min)Instruments

Soft X-ray Large Solid Angle Camera (SLC: 0.7–10 keV)sensitivity

50 mCrab /100 s (SLC)

pos. accuracy

0.1

platform

ISS/JEM (Selection in 2015, operation 2019–)

GW counterparts, black hole binaries, GRBs …

22

Impact of the Scale Down
• Sky Coverage– Instantaneous coverage– Daily Coverage

1/2
2/3

– Average effective area

2/3

– short transients– long transients

1/4
1/2

• Sensitivity• Detection rate23

iWF-MAXI proposal evaluation• Application for ISAS Small Project (Feb 2015)• Recommended by Advisory committee forSpace Science (July 2015)• Evaluation result by ISAS (December 2015)• Optimization of the size and cost reduction are evaluated.
• Insufficient system design, e.g. thermal control• Success criteria for the primary goal (GW detection) is notdefined due to uncertainty.
• Mission life limited by Japanese participation to ISS ( –2020).
• Overall evaluation: NOT SELECTED “The science goals of iWFMAXI will be mostly achieved by Indian ASTROSAT (launchedin September 2015), which is expected to perform all-sky
monitor sufficiently…”
24However,•iWF-MAXI evaluation

ASTROSAT Scanning Sky Monitor– Cannot obtain fine localization of transientsshorter than 10 min– Has low energy threshold > 2 keV
è Difficult to achieve iWF-MAXIʼs science goals• Japanese participation to ISS extended until
2024• LIGO detection of GW
è New proposal
25

Einstein Probe
Mission'proﬁle

Yuan 2015, Swift 10 years! Observing$modes$! Survey$mode$$$! XMray$followMup$observa6on$! Target$of$opportunity$$$$$$$! Orbit:$$! 600km$circular,$97min$period$! inclina6on$<30°$! Fast$Alert$downlink$(to$trigger$mul6M
wavelength$followMup$worldMwide)$$! The$VHF$network$(in$collab.$French)$! Chinese$relay$satellites$! Mass:$$380$kg$(payload$150kg)$! Power:$<$450w$(payload$200w)$! proposed$launch:$$~2020/2021$! Life$6me:$3(+2)$years$

credit: MicroSat 
26

Einstein Probe

Yuan 2015, Swift 10 years

PayloadWXT
Wide-field X-ray telescope (WXT)
Micro-pore lobster-eye focusing optics
Gas detectors (based line)
Focal length: 375mm
FoV 60°*60° (~1.1 sr)
FWHM ~ 4’
Bandpass: 0.5-4keV
Effective area ~4cm2 @1keV

Follow-up X-ray telescope (FXT)
Micro-pore K-B/Wolter-I optics
Si (CCD) or gas detector
Focal length: 1400mm
FoV 1°
Effective area ~60cm2 @1keV
FWHM ~ 4’
Bandpass: 0.5-4keV

FXT

WXT

FoV

FXT 1°x1°$

WXT
60°x60°$

27

Ultraviolet mission

Conceptual design of a micro-satellite
for Ultraviolet transient explore

Yoichi Yatsu (Tokyo Tech)
T. Ozawa, S. Harita, T. Yoshii, N. Kawai (School of Sci., Tokyo Tech),N. Tominaga (Konan Univ.), M. Tanaka (NAOJ), T. Morokuma (Univ. Tokyo)
S. R. Kulkarni (Caltech), T. Sakamoto (Aoyama Gakuin Univ.),
and N. Vasquez (Escuela Politécnica Nacional),
K. Tawara, S. Matsunaga (School of Eng., Tokyo Tech),on behalf of “Hibari” team

Backgroundu Rejection of WF-MAXI / iWF-MAXI
Ø ASTROSAT: a complemental detector(?) is on orbit
Ø Shrinking budget => < $2 million

Original model of WF-MAXIwith full-size BUS for JEM
Cost~ $50M

miniture version
with iSEEP-BUS
Cost~ $10M

80% is for Tests and Documentsu What can we do with <$2M?

LOFT

eROSITAHXMT Einstein Probe SVOM

Future missions have effective area larger than several thousands cm2!!

=> micro-satellite is too small comparing with these X-ray missions.

30

Survey of the other energy bandu Wide-field/High-cadence missions in other energy bands
Ø Radio: LOFAR, MWA, SKA etc
Ø IR/Opt: many robotic telescopesØ X/ γ: Swift, Fermi, MAXI, CALET, AstroSAT, CTA
Existing energy bands are almost covered by big projects.

u Where is the frontier in EM astronomy?
Ø MeV…(cannot use optics)
Ø Soft X…(technically difficult)hopeless

UV (NUV) is most hopeful because we can use:
- optics (but with special glass for UV)- CCD (back-illuminated CCD is required)

hopeless

MHz?



NUV
SoftX



MeV

Ø Radio… ??
Ø UV…

31

GW follow-up in UV
u Expected sourceØ NS-NS merger  r-nuclei
Ø kilonova (macronova)
The color, luminosity & variability are still model dependent!

u Possible scenario which favors UV emission
Ø free neutron beta-decay (Metzger et al. 2015)~ hours
mostly free Neutronsn → p + '( + )*~ daysmostly r-nuclei!∗ → ! + & + '( + )*free neutrons survive inouter shell of the Ejecta
This result in Blue, Brightand Fast EM emission

UV from free-N will be Brighter and Faster than IR.
Therefore the UV telescope can be suit for the GW follow-up.
32

Summary: UV emission from NS mergers
Timescale Wavelengths

Early thermal~ 15 minUVAB Mag
AB Mag@ 100 Mpc @ 200 Mpc
~26

Note

~27.5

Too rapid
coolingEarly
non-thermal~ 1 sec

UV

~>24
@ 1hr

~>25.5@ 1hr

Depends on
ambient
density

RadioacNvity(main ejecta)~10 days

Opt-NIR

~21

~22.5

Not UV~22*Uncertain*
assuming
M ~ 10-4 Msun

RadioacNvity(free neutron)~ 1 hrUV~20.5

Survey with Hibari: 22.5 mag -100 deg2 in 1 hr

33

Survey with Hibari
22.5 mag - 100 deg2 every 1 hr=> ~ 100 supernova detecNons / year
UV brightness

Uniqueness- UV wavelength- Con$nuous coverage

Wind breakout

Breakout

Cooling||||||||||||||||||||||

Day 1

Day 2

Thanks to Yatsu-san... Time

More interesNng with- coordinated (op$cal)
surveys from the ground- Rapid spectroscopy=> Unique probe of the last stage of stellar evoluNon
34

more science goals
u Ultraviolet pulse of Type 1a SN
Ø Interaction of ejecta on the companion staru Other science goals
Ø Neutrino events
Ø SN survey in UV can co-orperateØ

Yi Cao et al. 2015

with neutrino astronomer

Ø Tidal disruption events
Ø Active Galactic Nuclei, etc.
Ø Atmospheric emission(BG?)
- -

.-

-

35

Competitor/Collaborationfrom Wikipediau A lot of Telescopes…
u Recent NUV Imaging mission:
Ø GALEX (Φ1.2)FoV is not enough forØ UVOT/Swift (17’x17’)
GW astronomy
Ø ASTROSAT (28’)Ø ULTRASAT (210 deg2 21.5mag 900s)
may be the most recent shape

UV-CCD

Caltech/JPL/Israel

Demo in SpaceTokyo Tech small satellite team

Only the ULTRASAT can be used for GW follow-up.
••

Caltech was searching for a chance to demonstrate their detector on orbit.
We were searching for the UV-detector.
36

Mission Sequence:
Arrival of Gravitational Wave

Gravitational Wave•

Detection of GW•

Waiting for Alert

Ground Station
TokyoTech

GW isdetected!!
37

Command uplink for follow-up Obs
GW error circle•

Command uplink
for starting follow-up observation•

CMD should be sent ASAP•

real-time connection is needed38

Tiling observation #1

The satellite promptly starts observationz
Tiling Obs needs quick and stable Att control.

39

Tiling observation #2

We cannot transfer all the data to theground instantly.
zÞ On-board analysis (reduction &detection) is required!!

40

Tiling observation #3
UV TRANSIENTWAS
DETECTED!!

Extract information of the source:
Time, Magnitude, Position, etc.

z41

Alert to the Ground station••

Send an alert to the GS
this should be also ASAP

42

Multi-messenger astronomy
Satellites for X, γ, UV

Ground Observatories(Radio, IR, Optical)-GROWTH-JGEM-MITSuME (Tokyo Tech), etc.

43

Mission Requirements
Goal > 1 NS-NS merger/yr (Assuming 10 NS merger yr-1)

u Target Profile in NUV (Neutron Heating):Ø Error-circle:> 100 deg2
Ø Rise time:< 1 hrØ Flux:> 22 magØ Position Accuracy: < 10”

u Mission Requirements:

Ø Detection Limit:> 22magØ Cadence:> 2 cycle/hr
Ø Exposure: < 0.5 hr / (100deg2/FoV)Ø Obs Duration:> 1 hour (with batt.)
Ø Delay of Alert:< 30 min

We need:-Wide field telescope which can detect 22 mag-Attitude stability ~10”
-Quick MNV ~ a few deg/s
44

Such UV telescope will be useful for…
Limiting magnitude [nJy]
104

104

103

102

101

100

10-1

nd
ba
r’@
ay
)
/d
nm
0
SN
y 30
1
ay /da 80~
ay /d1/d SN SN V(
SN .1 .01 NU
0 0 @

1

Survey area Ωobs [degree2]

105

103
102
101
100
10-1
10-2
18

21

24

27

30

33

Limiting magnitude mx,lim [mag]Based on Tominaga et al. 2011

0.1 SN Shockbreakouts /day !?
45

Estimation of Detection Limitu Based on the UVOT/Swift DATA-

Readout Noise(RMS): 15.5 e- (5s x 60 frames)
Dark@-30ºC:
790 e-/pixel/300s

Day

Night

1200~1600Å

ΟΙ 2471Å

200mm
70% (Requirement)
80% (Caltech’s UV-CCD)ΟΙ 1356Å

Ø Diameter:
Ø OPT Trans Rate:Ø Q.E.:
Ø Electric Noise:ΟΙ 1304Å

u Estimation for the UV-telescope on Hibari

Ly-α 1216Å

Ø Diameter:
300mm
Ø Trans Rate x Q.E.: ~2.9 % (UVW1+UVM2)
22 mag(Vega)  152 photon / 1000s at NUV(UVW1+UVM2)

1600~3200Å

Ø Foreground (based on GALEX DATA):- Airglow(Local Time depend):~78.6 [ph/s/cm2/str/Å] (-6<LS<+6h avg.)- Airglow(Sun Angle depend):~675 [ph/s/cm2/str/Å] (120<S.A.180 )- Zodiacal light:~800 [ph/s/cm2/str/Å] (avoid ecliptic latitude)=> 97 e-/pix/300s(night) / ~ 1000 e-/pix/300s (day)At 200-300 nm with 300s exposure we can detectÞ 22.5 mag in night-sideÞ < 21.6 mag in day-side (airglow is x200 higher than night)

46

Design of Telescope
Allowed payload size:< Φ250 mmheight < 400 mm

u Requirements to the optics:
Ø D:
Ø FoV:< Φ200 mm => Exposure time > 300 s for 22mag> 17 deg2 <= 100 deg2
(30min/300s)

Ø focal L:
Ø PSF:< 430 mm (from the CCD format and FoV)
15um (~2 pixel)

u Base design:Ø Requirement:

Dichroic mirror

Short tube

 Riccardi-Honders OPTICS
Ø D200mm (F3.0)/$8k

u Modification
Ø BK7  Fused Quartz or Synthetic Silica for UV
Ø Shrink the focal length 600mm  430 mm

Tube
Reccardi-Honders OPTICSUVCCD Attitude
sensor

The manufacturer (Italy) confirmed the NUV-transmission rate with fused Quartz.
We must shrink the focal length. (The base design still provide ~9 deg2)

Estimation of data rateu Alert(uplink) / Detection Notice(downlink)Ø Time :24 bitØ Coordinate:
12 bit x 2 (x 5 points)
Ø Magnitude:
8 bit

Total: ~146 bit (~18 Byte)u Image Data
Ø Raw Data:

20642046 pixel  16bit = 8 MB/frame + Header

on board data reduction/compression

Ø Image combine:

10 sec  6 frame (& Cosmic-ray subtraction)

Ø Extract sub-regions- Object number:- sub-region:- Header:5~10 (Target + Reference stars)
50x50 pixel (5 kByte/sub-region)~1 kB (Coordinate+ Time + Temp,,,)DATA RATE ~ 50 kByte /min
Assuming 10 hour continuous observation,
the total amounts of telemetry will be ~30 Mbyte/day
48

System Block Diagram
CMD & Data Handling

RF-Communication

Attitude Control

UV TelescopeHigh Speed Data Bus

Power Supply

u System design is based on
the experiences in
TSUBAME projectu Controlled by CDH
u 2 kind of Data BUS
u Redundant design
49

Attitude Control Systemu Large Angle MNV… Attitude control by Variable Structureu Small Angle MNV… Reaction wheels
u Suppression of disturbance & vibration… RW
Simulation(Software in the Loop Simulation) concerned
disturbance, RW dynamics, measurement errors of Att sensors

10” Stability

10” stability is achieved Consistency of the Software Simulator was confirmed by TSUBAME
50

Optical mission

Transiting Exoplanet Survey Satellite
Ricker et al. 2014

53

OBSERVATION PLAN
Ricker et al.: Transiting Exoplanet Survey Satellite

Fig. 7 (a) The instantaneous combined field of view of the four TESS cameras. (b) Division of thecelestial sphere into 26 observation sectors (13 per hemisphere). (c) Duration of observations on thecelestial sphere taking into account the overlap between sectors. The dashed black circle enclosing
the ecliptic pole shows the region which James Webb Space Telescope will be able to observe at
any time.

1 orbit: 13-d observation + 0.6-d downlink

The overlap of the sectors is illustrated in Fig. 7.
2

54

8

Ricker et al. 2014(astro-ph 1406.0151)

Anticipated Results

SENSITIVITY

Ricker et al.: Transiting Ex

(a)

(

(

(b)

Apparent magnitude (l c)55

Ricker et al. 2014(astro-ph 1406.0151)

TARGETS AND DATA
• ~200,000 Preselected Stars• 2 min cadence• Almost all for Exoplanet+Asteroseismology• ~1000 targets/yr by guest observer proposal• 1st GO proposal due: fall 2016

• Data release every 4 month• ~20,000,000 Stars in FFI (Full Frame Images)• 30 min cadence• ΔM≈5 mmag for 106 stars and galaxies (Ic<14-15)• Delivery delay TBD (1 week ~ 6 months)

56

POSSIBLE SUBJECTS• GRBs: (orphan) afterglows• AGN: continuous light curve• Tidal disruption events at centers of galaxies• Gravitational Wave: optical counterparts/kilonovae• Supernovae and novae: pre-maximum light curve• X/gamma-ray binaries: multi-wavelength monitoring• Outbursts of BH/NS binaries• Black widow pulsars• Stars: super flares, super-orbital periodicities• Asteroids, comets, TNO, …

57

PLANS?
• Launch ~early 2018

• Guest Observer Proposal ~Summer 2017
• 2 min cadence targets• FFI• new transient pipeline?:(e.g. ASAS-SN)• coordinated observations for specific targets• Follow-up (delay?)• Sampling/monitoring spectroscopy, multicolor,…

58