Current/Future Space High Energy Astronomy
Missions of China and Possible Collaborations
Shuang-Nan Zhang（张双南）zhangsn@ihep.ac.cn
Particle Astrophysics Division
Institute of High Energy Physics
Chinese Academy of Sciences

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Institute of High Energy Physics (IHEP)
1.
2.
3.
4.
5.
6.
7.

Experimental Physics Division
Accelerator Division
Particle Astrophysics Division
Multi-disciplinary Research Division
Division of Nuclear Technology and Applications
Theoretical Physics Division
Computing Center

Total fulltime permanent staff: ~1500
Director: Yifang Wang

Beijing Electron-Positron Collider
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Particle Astrophysics Division
Fulltime permanent staff: ~170
Director: Shuang-Nan Zhang

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China’s Space High Energy Astronomy Missions– DAMPE (2015)– *POLAR (2016)– *Insight-HXMTDAMPE 2015(2017)– *GECAM (2020)– SVOM (2021)*GECAM 2020
– EP (2022)– *POLAR-2 (2024)– *eXTP (2027?)– *HERD (2025?) *POLAR-2 2024

*POLAR 2016

*HXMT 2017

SVOM 2021

EP 2022*HERD 2025?

*eXTP 2027?

*IHEP the PI institution
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悟空DAMPE (Dark Matter Particle Explorer)••

China’s first astronomical satellite, Dec. 17th, 2015.
Made the most precise measurement of the high energy
spectrum of cosmic electrons• Possible evidence for dark matter particle, but debated

PI: Prof. Jin Chang, Purple
Mountain Observatory, CAS
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天极POLAR: GRB polarimeter◼ China-Europe collaboration space program, onboard
China’s Space Lab., Sept. 15, 2016
◼ Most sensitive Gamma-Ray Burst polarimeter!

◼ Discovered 55 GRBs & obtained the largest sampleof GRB polarization with high precision!

Detector

Electronics

POLAR
On TG-2

PIs: Shuang-Nan Zhang (IHEP), Martin Pohl & Xin Wu (UniGe)
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POLAR’s main results: contradicting most models

170114A: 1st single peak GRB observed with pol. ang. evolution.
○ ordered B sync
● random B sync
+ Inv. Compton（Toma et al. 2009）

Comparison of obs. vs theory:➢ POLAR’s 5 GRB pol.
large-scale random B➢ GRB 170114A pol.

POLAR

Time-resolved high pol.
Time-integrated low pol
Pol. ang. varied significantly→→ Large-scale B evolved
significantly with time
Zhang et al. Nature Astronomy 2019
7/70

慧眼Insight-HXMTCASCAST◼ The 1st X-ray satellite in China, 06/15/2017◼ Features:◼ Large effective area @ > 30 keV◼ High timing resolution: single eventmode◼ Wide energy bands (1-250 keV narrow
FoV, 0.2-3 MeV as ASM）
◼ Status:◼ All instruments perform Focus on brightsources◼ Unrestricted number of ToOs
◼ Response time: hours to days
◼ Ad hoc ToO data public
immediately◼ In AO3; AO4 to be released soon and
PI: Shuang-Nan Zhang (IHEP)
open for all astronomers world wide
◼ To stay in orbit for >8 years
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Science payloads
Star
tracker

ME:SiPIN,5-30
keV, 952
cm2

LE:SCD,115 keV,
384 cm2

HE: NaI/CsI, 20-250 keV, 5000 cm2
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Effective area for pointing observations

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Effective Area for GRBs
GRB monitoring FOV: all sky un-occulted by the Earth
Insight-HXMT⚫ ~2000 cm2 ~ MeV range with single photon counting & energy
measurement, ~largest ~ MeV GRB & pulsar monitor ever flown
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Insight-HXMT scanning survey of the MW
Single scan sensitivity: 3-10 mCrab(spectral shape dependent)

Galactic Plane: (20°*20°)*18 + (20°*20°)*4•

11 center regions: 90 times/year (-60°~60°), 11 outer regions: 10 times/year

Sai, N. et al., 2020
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Scan light curve & reconstructed image
July 16 on Galactic center (LE 1-6 keV)

Direct Demodulation Method (Li & Wu 1993); Guan, J. et al., 2020

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Long-term monitoring of ~200 sources
1-250 keV: Cyg X-1, accreting BH

ME (7-40 keV):
Swift J0243.6+6124,
Accreting pulsar

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Neutron star cyclotron absorption line of Her X-1

Constant cyclotron line energy in Hercules X-1 -Joint Insight-HXMT and NuSTAR observations(@> 5 σ significance, Xiao et al. 2020)
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Highest-E Neutron star cyclotron absorption line
 GRO J1008-57：~90 keV →highest B directly measured in
the universe ~1013, ~ 4σ with
NuSTAR & Suzaku ~79 keV
 4 HXMT observations ~235 ks~ 20σ detection

Allow for phaseresolved and flux
dependent studies
Ge et al. 2020, ApJL

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Insight-HXMT discovery of GPD to RPD transition

Swift J0243.6+6124

Doroshenko, Zhang, Santangelo+ 201917/70

Historic event on April 28th 2020

CHIME

Insight-HXMTStare2CHIME/FRB Collaboration+; Bochenek+; Li+, 2021, Nature Astronomy
18/70Localization of the X-ray burst

CHIME

Insight-HXMTStare2: 95%

X-ray burst 3.7’ off SGR1935 with σ=10’’

Identification of the X-ray burst with SGR1935, Li+ (InsightHXMT team), 2021, Nature Astronomy
19/70

Insight-HXMT broad band light curves
27-250 keV
10-30 keV

1-10 keV

Photon index
Cutoff energy

Two narrow X-ray
peaks coinciding thetwin radio pulses (30ms separation),
identification of the
X-ray burst with
FRB 200428:
Insight-HXMT Atel
#13696/GCN#27675, Li+ (InsightHXMT team), 2021,
Nature Astronomy

Peak energy
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Insight-HXMT broad band spectrum
Both cutoff powerlaw &blackbody+powerlaw
provide almost the same
good fitting. BB+BB or PL
rejected.
CPL: photon index ~1.6,
Ecut~84 keV
BB+PL: Tbb~11 keV,
photon index ~1.9
Li+ (Insight-HXMT team),
2021, Nature Astronomy
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QPOs of BH binaries: < 30 keV → >200 keV

Ma, Tao, SNZ+ 2021, Nature Astronomy
22/70Dip in the lag-freq. spectra at QPO
All lags are relative to 1-2.6 keV; negative lag: behind

2.6-4.8 keV

150-200 keV

Ma, Tao, SNZ+ 2021, Nature Astronomy
23/70Lag contradicts Comptonization delay in corona:
Geometrical effect outside inner disk

Very large & soft lag:not precessing corona

Ma, Tao, SNZ+ 2021, Nature Astronomy

24/70New model of BH QPOs: L-T precession Jet

Ma et al. 2020, Nature Astronomy
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Broad band energy spectra with Insight-HXMT

You+2021, Nature Communications
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Decreasing reflection contradicts contracting corona

Reflection should increase,
but actually decreases

Kara+2020, Nature

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The contracting corona is an X-ray jet!

You+2021, Nature Communications
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Dedicated working mode for GRB⚫ GRB mode better energy range:◼ According to the simulation, det.
efficiency is good for >200 keV◼ GRB Epeak distribution⚫ GRB mode: ~30% of obs. time

GRB Epeak measured byFermi/GBM（Gruber+, ApJS, 2014）◼ When the targeted source is occulted
by the Earth in pointed observation◼ When HE regular mode is not very
useful in an observation

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Effective Area for GRBs & Pulsars⚫ Can detect GRBs in both
regular & GRB/LG modes(lower HV for PMT)

⚫ 500~3000 cm2 ~ MeV range
with single photon counting
and energy measurement,⚫ GRB monitoring FOV: all sky
un-occulted by the Earth

Luo et al.
2020

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Multi-instrument GRB spectral fitting

Luo et al. 2020

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Insight-HXMT GRB Statistics
Year

2017

2018

Month

6

7

8

9

10 11 12

1

2

3

4

5

6

7

8

All

2

10

9

12

8

8

8

11

8

7

11

6

8

7

4

short

0

3

5

3

5

2

1

1

1

1

3

2

2

2

0

Year

2018

Month 9 10 11

2019

Total

12

1

2

3

LG Mode：16；GCN：67/23 (1st)

All

4

4

5

6

7

6

12

163 gamma-ray bursts

short

1

0

2

1

0

2

2

39 short gamma-ray bursts~100 GRBs/year @ ~MeV, ~¼ short GRBs > ~1/6 by GBM~ 2000 cm2@0.2-3 MeV, ~μs timing resolution; but no real time
data or online trigger, data delay of hours to days

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GECAM
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor

Orbit:
600 km,29°
GECAMA

Detectors

Payload DomeGECAMBSpacecraft⚫

Characteristics
–
–
–
–

•

FOV：
100% all-sky
Energy band： 6 keV – 5 MeV
Sensitivity：<2E-8 erg/cm2/s
Localization： <1 deg (1-σ stat., 1E-5 erg/cm2)

Real-time alerts
–
–

GECAM
satellite(~160 kg for
each)

Trigger time, localization, duration, spectrum, etc.
Latency: 1-3 minutes

Launched on Dec 10, 2020

PI: Shaolin Xiong (IHEP)
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Effective Area

Advantages in Low energy band

Effective area vs. Energy and incident angle
GECAM vs. Fermi/GBM, Swift/BAT

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GECAM sciences

•

•
•
•
•
•
•
•
•
•
•

Gamma-ray Transients associated with
– GW sources– High Energy Neutrino (HEN)
– FRB
GRB
– ultra-long and ultra-soft, near-by, highz, etc.
SGR
TDE
X-Ray Bursts
X-Ray Binaries
X-ray Pulsars
Solar flare
Terrestrial Gamma-ray Flashes
Terrestrial Electron Beams
etc.

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Near Real-time alerts with Beidou Navigation system

•

•

•

In-flight alerts– Content: Trigger time, location,
duration, spectrum, etc– Latency: 1-3 minutes
Ground automatic alerts– Content: refined location, duration,refined trigger classification, etc.
– Latency: 10-30 minutes
Final alerts– Content: final results of GECAM– Latency: ~hours

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GECAM observations (till 2021-03-07 )•GRB– GRB 210307A, 210307B, 210228A,
210207B, 210204A, 210131A,
210126A, 210121A, 210120A,
210119A (Swift J1851.2-6148)•

SGR– SGR J1935+2154•

Type I burst from X-ray Binary– 4U 0614+09•

X-ray sources by Earth occultation– Sco X-1, Crab•

X-ray pulsars– Crab pulsar•

Solar Flares– ManyGECAM has published 12 GCNs and 1 Atel

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The first GECAM GRB with near real-time alert• BeiDou Navigation System (BDS)– Time latency ~ 60 seconds

Near real-time Light curve

Ground location with the BDS alert data

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Much more photons in low energy band

GECAM In-flight trigger

Fermi/GBM

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GECAM detection of Type I burst from NS X-ray
Binaries

PSD confirmation of 4U 0614+09

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Collaboration⚫ We’ve been developing the Transient
Position System (TPS) pipeline to do joint
localization for bursts, welcome to join!
➢ GECAM+HXMT+GBM+SPI-ACS+……
⚫ Welcome follow-up observations with
GECAM bursts➢ GRBs, SGRs, others⚫ GECAM follow-up analysis for interesting
events➢ GW events, FRBs, OT (opticaltransients)➢ Others⚫ Coordinate observations with GECAM➢ Share observation plans➢ ToO to adjust GECAM observationmode

TPS localization of a recent GRB

Contact: Shaolin XIONG (xiongsl@ihep.ac.cn)

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SVOM (Space Variable Object Monitor)
GRM

VT

IHEP 30 keV-5 MeV

400-650 nm, 650-950 n

MXT

Eclairs

0.3-5 keV

4-250 keV
PIs: Jianyan Wei,
National Astronomical
Observatories of China;
Bertrand Cordier, CEA, France
Launch: 2021/2022

450-900 nm

400-1700 nm

GWAC

GFTs
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Scientific Objectives of SVOMGRB phenomenon
GRB physics

GRB progenitors
Cosmology

Fundamental
physics

Diversity and unity of GRBs
Acceleration and nature of the relativistic jet
Radiation processes
The early afterglow and the reverse shock
The GRB-supernova connection
Short GRB progenitors
Cosmological lighthouses (absorption systems)
Host galaxies
Tracing star formation
Re-ionization of the universe
Cosmological parameters

Origin of high-energy cosmic rays
Probing Lorentz invariance
Short GRBs and gravitational waves
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The Einstein Probe (EP) mission⚫

The first mission that uses Lobstereye optics to monitor transients inthe soft X-ray band.

⚫

Proposed in 2012, selected in theend of 2017⚫

Launch date: ~2022

Mission Features• Very wide FoV 1.1 sr (3600 sq. deg.) grasp: ~10,000 deg2.cm2• Good angular resolution (~5’) and positioning accuracy (<1’)• Soft X-ray band: 0.5-5 keV• Sensitivity: >1 order of magnitude higher than current telescoeps• Autonomous X-ray follow-up (<10 arcsec localisation)• Fast alert data downlink and fast uplink for ToO (TBC)
PI: Prof. Weimin Yuan, National Astronomical Observatories of China
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Main science goals of the EP mission

Carry out systematic survey of soft X-ray transientsand variability of X-ray sources at unprecedented
sensitivity and high cadence
Discover otherwise quiescent black holes at almost
all astrophysical mass scales and other compact
objects by capturing their transient flares
Detect and localize the electromagnetic-wave
sources of gravitational-wave events by synergy
with gravitational-wave detectors
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POLAR-2 on China’s Space Station• Flight on-board China’s

Selected on June 12, 2019Space Station• Detailed polarization
measurements for 30 GRBs
per year• time resolved polarization
measurements for 10 GRBs
per year• launch ~2024, operation for
2 years

PIs: Xin WU (UniGE)
Shuang-Nan Zhang (IHEP)

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High Energy cosmic-Ray Detection (HERD)• HERD: flagship and landmark scientific experiment onboard the China's
Space Station, China-led large international collaboration, ~2025• Scientific goals– Dark matter search with high energy electrons and gamma-rays– Precise CR spectrum and composition measurements up to knee energy– Gamma-ray monitoring → trigger for CTA or other telescopes

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HERD current baseline design
Silicon Strip
ChargeDetectors
Plastic Scintillators
e/γ ID
ChargeFiber Tracker
Tracksγ conversion

3D Imaging
Calorimeter
EnergyParticle ID

Transition Radiation
Detector
TeV energy scalecalibration

PI: Shuang-Nan Zhang (IHEP);
Europe Coordinator: Giovanni Ambrosi (INFN, Perugia)
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HERD specifications
Value

Item
Energy range (e/γ)

10 GeV - 100 TeV (e); 0.5 GeV - 100 TeV (γ)

Energy range (CR)30 GeV - 3 PeV

Angular resolution

0.1 deg.@10 GeV

Charge resolution

0.1-0.15 c.u

Energy resolution (e)1%@200 GeV

Energy resolution (p)20%@100 GeV – PeV

e/p separation~10-6

G.F. (e)>3 m2sr@200 GeV

G.F. (p)>2 m2sr@100 TeV

Field of View+/-70 deg (targeting +/-90 deg)

Lifetime>10 years

Mass~4000 kg

Envelope~3000*2300*1550 mm3
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Total e+/- spectrum• HERD can confirm ~TeV features in the electron spectrum• HERD can distinguish different origins of excess and newfeatures in the electron spectrum.
CALET
PRL 2018

HERD can verify the sharp peakat the DAMPE spectrum in 6
month observation.

“The flux in the 1.4 TeV bin of
DAMPE’s spectrum is not compatible
with CALET results at a level of 4σsignificance, including the systematic
errors from both experiments.”
50/70

HERD Proton and Helium spectra(5 years , Hoerandel fluxes )For the first time one single experiment will be able to probe all the funny structures in
the CR spectra: Hardening, Softening, Possible new structure, Knee
51/70

Proton knee below 1 PeV ?
HERD 5yr> 5 s effect52/70

Nuclei up to Fe (HERD , 5 years , Hoerandel fluxes )Detection of the “standard” proton knee

Precision measurement of hardening,softening, and spectral indexes for most of
the nuclei (primaries and secondaries)

The dynamic range is a fundamental
issue even more important thangeometric factor itself
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B/C measurement with HERD

B/C is adopted to determine the CR propagation
parameters and origin of break at the primary nuclei spectra
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HERD Gamma-ray sky survey

HERD: 1 year
FERMI/LAT: 1 year
LHAASO: 1 year
CTA: 50 hours

Expected HERD gamma-ray sky survey sensitivity (5σ)
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eXTP: enhanced X-ray Timing and Polarimetry--The next international flagship X-ray mission: 2027?
一奇二星三极端
⚫ Sciences➢ BH Singularity➢ Neutron or Quark Star?
➢ Extreme gravity/magnetism/density⚫ Capabilities➢ Spectral, polarization, timing, imaging➢ Large eff. Area (~3.8 m2@6 keV)
➢ High spec. resol.(<180 eV@6 keV)
PayloadConfiguration

Eff. area (m²)

Spectroscopy Focusing
Array (SFA)

9 telescopes

0.54m²@1keV

40 modules

3.4m²@8keV

Large Area Detector (LAD)

Polarimetry Focusing Array
4 telescopes(PFA)
Wide Field Monitor (WFM)

6 cameras

380cm²@3keV
3.2 Sr （FOV）

Timing res. (μs)
10
10
500
10

PI: Shuang-Nan Zhang (IHEP); Europe: Marco Feroci (INAF, Rome)
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White papers on eXTPFive refereed papers have been accepted for
publication in a special issue of SCIENCECHINA Physics, Mechanics & Astronomy• S.-N. Zhang, A. Santangelo, M. Feroci,
Y.P. Xu, et al., The enhanced X-ray Timing
and Polarimetry mission - eXTP
• A. L. Watts, W.F. Yu, J. Poutanen, S.
Zhang, et al., Dense matter with eXTP
• A. De Rosa, P. Uttley, L.J. Gou, Y. Liu, etal., Accretion in Strong Field Gravity
with eXTP• A. Santangelo, S. Zane, H. Feng, R.X. Xu,
et al., Physics and Astrophysics of Strong
Magnetic Field systems with eXTP
• J. J. M. in 't Zand, B. Enrico, J.L. Qu, X.D.
Li, et al., Observatory science with eXTP
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Spectral-Timing for extreme gravity
General Relativity predicts precise
orbital and epicyclic frequencies
at each radius

eXTP:
10x the SNR

Motta et al. 2013

Strong gravity dynamicalfrequencies just detected incurrent (RXTE) data
• eXTP diagnoses strong field gravity
very precisely by:– timing of the flux variations– time resolved spectroscopy
at very high signal to noise• Uses known phenomena•

Wellons et al. 2013

Orbiting inhomogeneities makefrequencies observable

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Neutron Stars EoS
3.0

TE
RX

2.5

Mass (MO• )

2.0

eXTP
LOFT

1.5
1.0
0.5

(eXTP)
0.0
8

eXTP WILL STUDY NUCLEONIC MATTER IN A
UNIQUE REGIME, AND EXOTIC STATES OF
MATTER (E.G., QUARK STARS) THAT COULD
NEVER EXIST IN THE LABORATORY.

10

12
Radius (km)14

16USING ONLY KNOWN SOURCES, PULSEPROFILE MODELLING MEASUREMENTS
WILL MAP THE M-R RELATION AND
HENCE THE EQUATION OF STATE (EOS).

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eXTP Mission overview
Parameter

Value

Orbit

550 km, inclination 0°

Pointing

3-axis stabilized, < 0.01°(3σ)

LaunchLM7 + upper stage, @Wenchang

Launch mass

4500 kg

Telemetry

3.2 Tb/day (X-band or Ka-band)

Burst alert

BeiDou Navigation Satellite System;
VHF transmitter (SVOM); Tracking
and Data Relay Satellite System

GroundStations

Sanya (China), Malindi (Italy)

Missionduration

5 years (goal 8 years)

Launch date

~ 2027 (in phase B now)

16.8 mm × 3.95 mm × 11.4m

Accommodation concept by CAST
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eXTP Scientific Payload:
SFA – Spectroscopy Focusing Array• Large collecting area achieved bymultiple optics with short focal length.
• 9 grazing incidence Wolter-I optics with
5.25m F.L., 40 shells/module• Non-imaging, 1′ (HPD), 3′ (W90), 12′ FoV• 19-cell SDD array: multi-pixel to enablebackground subtraction• Energy range: 0.5-10 keV• Energy resolution: ≤ 180 eV @ 6keV
• Time resolution: 10μs
• Absolute timing accuracy: 2μs• Dead time: < 5% @ 1Crab• Sensitivity: 4.1x10-15 erg/cm2/s (3σ, 10ks)

×9

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eXTP Scientific Payload:
SFA – Spectroscopy Focusing Array• Large collecting area achieved bymultiple optics with short focal length.
• 9 grazing incidence Wolter-I optics with
5.25m F.L., 40 shells/module• Non-imaging, 1′ (HPD), 3′ (W90), 12′ FoV• 19-cell SDD array: multi-pixel to enablebackground subtraction• Energy range: 0.5-10 keV• Energy resolution: ≤ 180 eV @ 6keV
• Time resolution: 10μs
• Absolute timing accuracy: 2μs• Dead time: < 5% @ 1Crab• Sensitivity: 4.1x10-15 erg/cm2/s (3σ, 10ks)

5400cm2@1keV
4100cm2@6keV

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eXTP Scientific Payload: LAD – Large Area Detector
•
•
•
•
•
•
•
•
•
•
•

Spectral and timing observation
40 modules on 2 deployable panels
Collimated, large area SDD detector
Energy range: 2-30 keV (goal 50keV)
Energy resolution: < 240eV @ 6keV
Field of View: 1°(FWHM)
Time resolution: 10μs
Absolute time accuracy: 2μs
Dead time: < 0.5% @ 1CrabBackground: < 3mCrab
Total effective area: 3.4m²@ 8keV

moduleSDD: 2x112 anodes, pitch = 970μm
MCP collimator

Thermal/opticalfilter63/70

eXTP Scientific Payload: LAD – Large Area Detector
•
•
•
•
•
•
•
•
•
•
•

Spectral and timing observation
40 modules on 2 deployable panels
Collimated, large area SDD detector
Energy range: 2-30 keV (goal 50keV)
Energy resolution: < 240eV @ 6keV
Field of View: 1°(FWHM)
Time resolution: 10μs
Absolute time accuracy: 2μs
Dead time: < 0.5% @ 1CrabBackground: < 3mCrab
Total effective area: 3.4m²@ 8keV

30000cm2@6keV

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eXTP Scientific Payload:
PFA – Polarimetry Focusing Array• Large collecting area achieved bymultiple optics with short focal length.
• 4 grazing incidence Wolter-I optics with
5.25m F.L., 40 shells/module• Imaging, resolution ≤ 30″(HPD, goal
15″)
• Field of view: 8′• Gas Pixel Detector (GPD): photoelectron tracking• Energy range: 2-8 keV• Energy resolution: ≤ 1.8 keV @ 6keV
• Time resolution: 500μs• Absolute timing accuracy: 2μs• MDP: < 1.6% (106s, 1mCrab)

×4

Titanium frame

Beryllium window

Ceramic spacer

GEM foil
GEM support
ASIC chip
Readout board

Designed by the
INFN-Pisa group(Bellazzini et al.)

GPD prototype(Tsinghua)
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eXTP Scientific Payload:
PFA – Polarimetry Focusing Array• Large collecting area achieved bymultiple optics with short focal length.
• 4 grazing incidence Wolter-I optics with
5.25m F.L., 40 shells/module• Imaging, resolution ≤ 30″(HPD, goal
15″)
• Field of view: 8′• Gas Pixel Detector (GPD): photoelectron tracking• Energy range: 2-8 keV• Energy resolution: ≤ 1.8 keV @ 6keV
• Time resolution: 500μs• Absolute timing accuracy: 2μs• MDP: < 1.6% (106s, 1mCrab)

380cm2@3keV

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eXTP Scientific Payload: WFM – Wide Field Monitor
•
•
•
•
•
•
•
•
•

3 units (6 cameras)
2D Imaging, 5′ (FWHM) resolution
Location accuracy: ≤ 1′
Field of view: ≥ 3.2 Sr (at 20%
response)
Energy range: 2-50 keVEnergy res.: ≤ 300eV @ 6keVTime resolution: 10μs
Absolute time accuracy: 2μs
Peak sensitivity (5σ): 1Crab (1s),
5mCrab (50ks)

Camera module

SDD: 2x384 anodes, pitch = 169μm

1.5D coded mask
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eXTP Scientific Payload: WFM – Wide Field Monitor
•
•
•
•
•
•
•
•
•

3 units (6 cameras)
2D Imaging, 5′ (FWHM) resolution
Location accuracy: ≤ 1′
Field of view: ≥ 3.2 Sr (at 20%
response)
Energy range: 2-50 keVEnergy res.: ≤ 300eV @ 6keVTime resolution: 10μs
Absolute time accuracy: 2μs
Peak sensitivity (5σ): 1Crab (1s),
5mCrab (50ks)

WFM field of View. (Background map
courtesy of T. Mihara, RIKEN, JAXA,
and the MAXI team)

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China is active in space high energy astronomy• DAMPE, *POLAR, *Insight-HXMT, *GECAM launched in
2015/16/17/20– Insight-HXMT is very flexible in ToOs and monitoring bright transientswith high cadence and long observations; GECAM as ASM has good
low energy response & near real-time alert capability• SVOM, EP, *POLAR-2 to be launched in 2021/22/24– Large FoV & deep high energy monitoring, with quick & deep
X-ray/optical follow-up capabilities; GRB polarimetry.
• Two large future missions– *HERD: To provide sensitive gamma-ray (GeV to TeV)sky monitoring, on China’s Space Station, 2025?
– *eXTP: To provide X-ray spectral-timing-polarimetry withpowerful WFMs, space X-ray observatory, 2027?
*IHEP is the PI institution in China
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We are eager to collaborate!
• Insight-HXMT: most data are public; AO-4 to beannounced in April, guest observers program
open worldwide; Galactic plane scanning survey
is complementary with MAXI.
• GECAM: near real-time burst alerts; NS type-I
burst monitoring is complementary with MAXI.
• SVOM and EP: near real-time burst alerts; rapid
follow-up observation capability.
• POLAR-2: gamma-ray burst polarization.
• eXTP & HERD: we welcome contributions fromJapan and other countries at all levels.
Many thanks and we look forward for collaborations!
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