Future X-ray/gamma-ray
follow-up observations for themulti-messenger transients
Masanori Ohno (Hiroshima University)

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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2017’ : a dawn of the MM follow-up
observation era

Abbott+17

Troja+17

Tanaka+17(Atel#10791)

https://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/SourceReport.php?week=47
7&flare=27

preliminary

27th Mar. 2018preliminary• EM counterpart from NS-NS
merger event
GW170817/GRB170817A• Gigantic campaign of follow-up
observation in any EM
wavelengths successfully carriedout• More detections/follow-up obs.
are needed for modeling andshort GRB association• High-E IceCube ν and blazar
activity was found for IceCube170922A/TXS0506+056• Future continuous monitoring
for this candidate and further
detection is expected

Muti-Messenger Workshop, Chiba University, Japan

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Current MM follow-up system
Time, position
probability.. etc

Internal GCN
GraceDB (internal)

Detection or not
Updated position
Flux upper limit ..etc

Follow-up
observation/analysis
By ground/space
EM telescopes

Gravitational
wave

KAGRA

GRB coordinatenetwork (GCN)

Energy,Time,
Position..etc

Electromagneticsignals

High energy
neutrino
27th Mar. 2018

NASA Muti-Messenger Workshop, Chiba University, Japan

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Why X-ray/gamma-ray ?
• NS-NS(BH) merger and short GRB association !
• X-ray/gamma-ray spectral features from NS-NS merger
environment (circumstellar medium, r-process elements)• Monitoring observation w/ wide field of view instruments
Abbott+17

https://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/Sourc
eReport.php?week=477&flare=27
preliminary

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Sensitivity in previous/current
X/Gamma-ray observations• ~10-15 erg cm-2 s-1 in soft X-ray• 10-13~10-10 erg cm-2 s-1 for Hard Xray to γ-ray

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Sensitivity in “future” X/Gamma-ray
observations• Improved sensitivity in soft/hard X-ray band
• Continuous monitoring in gamma-ray band
• High-resolution spectroscopy

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Sensitivity in “future” X/Gamma-rayobservations• Improved sensitivity in soft/hard X-ray band
• Continuous monitoring in gamma-ray band
• High-resolution spectroscopy

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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X-ray Astronomy Recovery Mission(XARM) : 2021~

FOV/pix

ΔE (FWHM@6keV)

Energy band

Resolve(XMA+X-raymicrocalorimeter)2.9’□/6x6pix

7 eV(goal 5 eV)

0.3—12 keV

Xtend(XMA +X-ray CCD)

38’□/1280
x1280 pix<250 eV at
EOL (<200eV at BOL)

0.4—13 keV

spectroscopy@6keV

FoVimaging

Tashiro 17th heapa workshop
27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

Soft X-ray
Area

Hard X-rayArea
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Focusing On Relativistic universe and Cosmic
Evolution (FORCE): 2025(?)~• 10 m of focal length• 3 pairs of X-ray supermirror + detector

27th Mar. 2018

Mori 17th heapa workshop

è 2~3 x 10/38
erg cm s sensitivity (10-40 9keV)-15Chiba University,-2Japan–1
Muti-Messenger Workshop,

Physics of Energetic and Non-thermal plasmas
in the X resion (PhoEniX)
Soft X-ray & Hard X-ray imaging spectroscopy
Of solar flare+Soft gamma-ray spectroscopy and polarimetry
With soft gamma-ray spectropolarimeter(Same as the Hitomi-SGD)

Narukage 17th heapa workshop
27th Mar. 2018

Spectroscopy andpolarimetry havebeen performed for
the Crab nebula with
only 5 ks exposure !

Muti-Messenger Workshop, Chiba University, Japan

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Sensitivity in “future” X/Gamma-ray
observations

What can we do for MM follow-up
With these future instruments ?
• Improved sensitivity in soft/hard X-ray band
• Continuous monitoring in gamma-ray band
• High-resolution spectroscopy

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Science Case: NS-NS merger
Ioka & Nakamura+17

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Science Case: NS-NS merger
Ioka & Nakamura+17① on-axis
GRB afterglow③Late time activityof merger remnant

27th Mar. 2018

② radioactive
decay of r-processelements

Muti-Messenger Workshop, Chiba University, Japan

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Science Case: NS-NS merger
Ioka & Nakamura+17① on-axis
GRB afterglow③Late time activityof merger remnant

27th Mar. 2018

② radioactive
decay of r-processelements

Muti-Messenger Workshop, Chiba University, Japan14/38

① On-axis GRB afterglow• Quick follow-up observation (<1-day) of GW event may detect a nominal X-ray afterglow
è Strong evidence for association of short GRB and compact merger• …+ spectral feature by high resolution spectroscopy reveal circumstellar environment(XARM-resolve, ATHENA)• Only expected from SN but NS-NS merger (3rd GW telescopes) ??
Modified fromTashiro, MO+14
Ar XVIII

20 ks observations
by XARM(assume same
response as Hitomi)

Mg XI
Si XIVS XVIReeves+04 reported soft X-ray lines
From GRB011211 in XMM-Newton
SpectrumF(2-10 keV)~10-12 erg s-1 cm-2
27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Expected event rate
Using 6-years Swift-XRT data, expected event rate for each
Flux level and observation start time is calculated (Tashiro, MO+14)

20-30evts/6 years= 3-5 evts/year<2day follow-up is needed toobtain ~a few event/year for
Bright event (10-12 erg cm-2 s-1)
Need discussions whether
XARM can slew so quickly by ToO…

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Science Case: NS-NS merger
Ioka & Nakamura+17① on-axis
GRB afterglow③Late time activityof merger remnant

27th Mar. 2018

② radioactive
decay of r-processelements

Muti-Messenger Workshop, Chiba University, Japan

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② gamma-rays from r-process elements• Detection of gamma-ray due to specific lines can provide a evidence for the r-process(same case for the 56Ni and 56Co from Ia SN (Churazov+14., Terada+17 ..etc))
in hard X-ray and gamma-ray band è NuSTAR, FORCE, PhoeNIX-SGD !
• Expected light curve and spectra are provided by Hotokezaka et al. 2016

FORCE• Any hope ? for >1day, 3Mpc, 0.01Msun case
• Dimmer by ~2 order of magnitude for
GW170817 (40Mpc)• Too challenging..
27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Science Case: NS-NS merger
Ioka & Nakamura+17① on-axis
GRB afterglow③Late time activityof merger remnant

27th Mar. 2018

② radioactive
decay of r-processelements

Muti-Messenger Workshop, Chiba University, Japan

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③ late time activity of merger remnant• The fate of the remnant depends on the EOS and total mass of NS-NS(massive NS è BH (w/ disk), low-mass NS-NS è long lived massive NS ?)• Both cases, late time activity (BH disk emission, pulsar wind) could be expected• Origin of extended emission of short GRB ?
Expected Long-lived X-ray (left) and gamma-ray (right) light curve for pulsar case
Murase+17
Thick:@1keV
Thin:@30keV
Fermi
FORCE
Chandra/XMM

Thick:@1GeV
Thin:@100GeV• Detectable for most future X-ray/gamma-ray follow-up depend on remnant condition?
• But no detection is reported.
• Future monitoring is still valuable for detection/constraint on the remnant models
27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

20/38

③ late time activity of merger remnant• Late time X-ray emission may be illuminate the dynamical ejecta and absorbed by
the r-process element è spectral feature ?
Inoue 18

Wanajo+14
1st3rd2nd

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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③ late time activity of merger remnant• Late time X-ray emission may be illuminate the dynamical ejecta and absorbed by
the r-process element è spectral feature ?
XARM spectrum 1Ms@3x106 s
preliminaryResolve(SXS)
Xtend(SXI)Ge K-edge (11.1 keV)

Inoue 18

10keV
(PL index=1.0,~3x10-13 erg s-1 cm-2@10keV
optical depth of edge: 0.5)

27th Mar. 2018

12keV

Detectable ?, but XARM is not thebest instrument ?
Fluorescence line ?

Muti-Messenger Workshop, Chiba University, Japan

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Science Case: NS-NS merger① on-axis GRB afterglow- Evidence of short GRB
association & study ofenvironment materialof NS-NS merger- <1day observation by
XARM may detect
spectral features

Ioka & Nakamura+17② radioactive decay of rprocess elements- Direct evidence of rprocessing- Still challenging.. Anyhope for very nearby
event by
FORCE/PhoenixSGD ?

③Late time activity ofmerger remnant- Evolution of themerger for its
EOS/mass relation- Bright X-ray/gammaray (+absorptionfeature) is expected
depending on the27th Mar. 2018
Muti-Messenger Workshop, Chiba University, Japanremnant model

23/38

Localization is important..
• Localization error of GW telescopes is several tens of degree^2 and IceCube isalso several degree^2• Much larger than typical field of view of X-ray telescopes : ~30’x30’ (and ofcourse optical telescopes)• Localization by all-sky gamma-ray instruments is important at least within~10’ and hopefully ~1’ !

R= 3’~15’
27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Localization is important..
Case for GW170817

5 deg : ~30 galaxies 😿
0.1 deg (6 arcmin) : 1 galaxy ! 😺

Caulter+17
27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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What do we need ?
Field of view(str)INTEGRAL-SPI-ACS
4π ー

INTEGRAL-SPI-ACS(w/ IPN)

No instruments withLarger FoV (>2π str)
+High Loc. Acc. (<arcmin)

CALET-CGBM
FermiAll-sky coverageè Poor (even no) loc. acc.GBM

è Discovery space
2π ーAGILE

CALET

Fermi-LAT

MAXI

X-ray mirror, slit/coded mask
è High loc. acc. But narrow FoVSwift-BAT
Swift-XRT|
No localization

17th Mar. 2018|degree|arcmin|Localization accuracy
arcsecSpring Annual meeting of Astronomical Society of Japan, Chiba University
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Solution1: position sensitive detector w/
moderate FoV
High-z Gamma-ray bursts for Unraveling the Dark Ages Mission (Hiz-GUNDAM)• High sensitive prompt emission observationand localization of high-z GRB in X-ray band
• Self follow-up observations of afterglow inNIR band to detect Lyman-α dumping wing
+ Promotion of MM (GW) astronomy !

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Solution1: position sensitive detector w/
moderate FoV
Kanazawa-SAT3 : Micro-satellite for alert the position and timing of X-ray transient

Launch target

FY2019Satellite size 50 kg, 50 cm3
Science instrument
X-ray imaging detector（T-LEX）
Coded mask + Silicon-strip detector
2 – 20 keV, 15arcmin, 1 sr, 100 cm2
Gamma-ray Detector（KGD）
CsI(Tl)scintillator
20 – 200 keV, 3 sr, 50 cm2

27th Mar. 2018

Muti-Messenger Workshop, Chiba University, Japan

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Solution2: fleet of nano-satellite w/
triangulation

Hurley+13

p dozen satellite constellation
è all-sky coverage(no earth shadow)huge effective area
GRBCube : Japanese/Hungarian
collaboration project
27th Mar. 2018

p localization by photonarrival timeHigh timing synchronization byè μ-sec timing accuracy
results several arcmin
localization accuracy ?

Muti-Messenger Workshop, Chiba University, Japan

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Detector Design
75 mm

MPPC
150 mm
5 mm !

• one side of lateral extension (+inside) :~268 cm2 x 9mmt (+~80 cm2)
basic idea to maximize geometrical area
• challenging for such “large and thin”
detector with small readout area
27th Mar. 2018

CsI scintillator readout by
multi pixel photon counter (MPPC)
is now being evaluated as the firstfeasibility study for their large lightyield, compact readout area and low
operational high voltage.

Muti-Messenger Workshop, Chiba University, Japan

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Single channel readout ch1
Single channel readout ch2
Coincidence sum241Am

59.5 keV

Energy threshold of ~10 keV is achievedfor both single/multi channel readout(comparable to Fermi/GBM)
Energy range: 10-1000 keV (TBD)
27th Mar. 2018

GRB incident zenith angle

Spectral feasibility

GRB incident azimuthal angle

Effective area for any incident angle
is estimated by the Monte-Carlosimulation. 200~300 cm2 iscomparable/better than Fermi-GBM.
This result is input to localization
simulation

Muti-Messenger Workshop, Chiba University, Japan

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Localization simulation
10-1000 keV
sat0 – sat1

sat0 - sat2
GRB!
sat3

sat2

sat0
sat0 – sat3
sat1
1.0

Time since trigger (s)Simulated photon arrival time isestimated by the cross correlation
Spring Annual meeting of Astronomical Society of Japan, Chiba University
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analysis

Satellite attitude, GRB position,
predicted photon arrival time isestimated.
17th Mar. 2018

0.5

Localization !
Intersection of annuli
è GRB position !

Declination [degree]

chi2map
30.6
30.4⭐: input position
1, 2, 3 σ region

30.2

⭐

30
29.8

Best fit position
R.A. = 20.0 (+- 0.06) deg
Dec. = 29.9 (+-0.10) deg

29.6
29.4
29.2
19.4

Mathematical approach isneeded17th Mar. 2018

19.6

19.8

20

20.2

20.4
20.6
Right Ascension [degree]

GRB position and error is estimated bysimple χ2 minimization (Tanaka et al.
2017)~0.1 deg1σ (~10 arcmin) accuracy isachievable for bright/high-visibility caseSpring Annual meeting of Astronomical Society of Japan, Chiba University

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Systematic analysis for FermiGBM short GRB-5

Log10 Fluence

GRB brightness (fluence)
Log10 Fluence

Localization accuracy of our concept is examined for all short GRBs
listed in Fermi 3rd GRB Catalog (Bhar+16 T90<2s: 326 samples )sattelites combination
99 satellites
detection
55sattelites
combination
satellites
detection
60’
-5.5

-6

-6.5

-7

GRB170817A

-7.5

-8
-2

-1.5

-1

-0.5

0Log10 duration (T90)

1 -5

1

0.9

0.9

-0.8
5.5

0.8

0.7
-6
0.6

0.7

-0.5
6.5

0.5

0.4

0.4

-7
0.30.30.6

0.2-7.5

0.2

0.1

0.1

0 -8-2-1.5-1-0.5

0Log10 duration (T90)0GRB duration••High localization accuracy for good photon statistics (brighter/longer)
5-10 arcmin accuracy for a good condition
17th Mar. 2018

Spring Annual meeting of Astronomical Society of Japan, Chiba University

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Event rate and localization
Sat. num.

Visibility prob. Number ratio of Fermi sGRB for each localization
accuracy<10ʼ<15ʼ

<20ʼ

91.8%

27%

30%

37%

87.6%

26%

29%

33%

716%

5%

14%

19%

626%

2%

8%

13%

525%

1%

3%8%

415%1%1%1%~12 % of Fermi-GBM sGRB: <20ʼ localization accuracy
Fermi GBM sGRB rate: 336 sGRBs/6 years ~ 60 sGRBs/yearè ~10 sGRBs/year for <20ʼ localization accuracy with our GRBCubeconcept ! (0.5-1 for GRB170817A..)
17th Mar. 2018

Spring Annual meeting of Astronomical Society of Japan, Chiba University

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Towards a Network of GRB
Detecting SmallSatsʼ !
All-sky coverage with ~arcmin localization accuracy by the fleet ofnano-satellite : similar ideas are rapidly growing in the world
HERMESled by Itelian National
Institute ofAstrophysics (F. Fiore)burstCubeled by NASA/GSFC (J. S.
Perkins)• >100 of larger (6U) satellite
è arcsec accuracy !??
• Demonstration mission isapproved
17th Mar. 2018

Single 6U cubesat with multiple
CsI detectors<7°localization accuracy(Racusin+17)

blackCat (U.S./Penn State), GECAM (China/CAS) ..
Etc.

Spring Annual meeting of Astronomical Society of Japan, Chiba University

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Future GRB follow-up
Field of view
(str)
INTEGRAL-SPI-ACS
4π ー

INTEGRAL-SPI-ACS(w/ IPN)

CALET-CGBM

GRBCubeFermiGBM

2π ーAGILE

CALET

Fermi-LAT

MAXI
Swift-BAT
Swift-XRT|No localization

17th Mar. 2018|degree|arcmin|Localization accuracy
arcsecSpring Annual meeting of Astronomical Society of Japan, Chiba University
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Summary• X-ray/Gamma-ray follow-up of MM transients is important forrevealing the nature of their sources• Future X-ray/Gamma-ray instruments such as XARM, FORCE.. etc.
are expected to increase the sensitivity for searching spectralfeatures and hard-Xray /gamma-ray emission from MM transients• Some theoretical models can be tested or serendipitous discovery
is always anticipated
Localization by gamma-ray observation is another key forfuture MM astronomy• Many missions for GRB localization is proposing• All-sky+arcmin localization is possible with fleet ofnano-satellite• Such world-wide network of GRB detection by small
satellite probably becomes future main stream of
GRB localization
27th Mar. 2018

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