1. The SVOM mission Bertrand Cordier & Wei Jianyan
on behalf of the SVOM consortium

2. GRB Observation scenario
waiting
Auto slew
T0 GRB trigger
On board
T0+5min
VT,MXt observation
On Ground
VHF
F SC
Other SC mission center
T0+30s
Inside SVOM
Outside SVOM
T0+1min
C SC
GCN
GRB coordination distribute
Large telescope

3. SVOM system (simplified)PF
GRB
TM/TC
X-band
Xichang launch site
X-band
S-band
VHF
LM-2C
GFT
CCC
Mission Center
Science Centers
French Payload Operation center

4. SVOM system (detailed)

5. The SVOM mission
Bilateral collaboration between France (CNES) and China (CAS, CNSA)
(with the contribution of the University of Leicester and the Max Planck Institut für Extraterrestische Physik and Universidad Nacional Autónoma de México)
« Space-based multi-band astronomical Variable Objects Monitor »
Launch in Dec. 2021, for 3+2 years

6. SVOM instruments I ECLAIRs (CNES, IRAP, CEA, APC)
40% open fraction
Detection plane: 1024 cm²
6400 CdTe pixels (4x4x1 mm3) → see Armelle Bajat talk
FoV : 2 sr (zero sensitivity)
Energy range: keV
Localisation accuracy <12' for 90% of the sources at detection limit
On board trigger and localization: about 60 GRBs/year
→ Stéphane Schanne talk on the trigger
→ Frédéric Daigne talk on the SVOM GRB sample
Gamma-Ray Monitor (IHEP)
3 Gamma-Ray Detectors (GRDs)
NaI(Tl) (16 cm Ø, 1.5 cm thick)
Plastic scintillator (6 mm) to monitor particle flux and reject particle events
FoV = 2 sr per GRD
Energy range: keV
Aeff = 190 cm² at peak
Rough localization accuracy
Expected rate: ~90 GRBs / year

7. SVOM instruments II Microchannel X-ray Telescope (CNES, CEA, UL, MPE)
Micro-pores optics with square 40 micron size pores in a “Lobster Eye” configuration
pnCCD based camera
FoV = 64x64 arcmin²
Focal length: 1 m
Energy range: keV
Aeff = 27 1 keV (central spot)
Energy resolution: ~ keV
Localization accuracy <13” within 5 min from trigger for 50% of GRBs (statistical error only)
→ Laura Gosset talk on MXT
Visible Telescope (XIOMP, NAOC)
Ritchey-Chretien telescope
Ø = 40 cm, focal length = 360cm
FoV = 26x26 arcmin²
Covering ECLAIRs error box in most cases
2 channels: blue ( nm) and red ( nm)
2k * 2k , 13,5 µm for both CCDs
Sensitivity MV=22.5 in 300 s
Will detect ~80% of ECLAIRs GRBs
Localization accuracy <1”
Capability of high redshift GRB detection, up to z = 6,5

8. Ground instruments Chinese Ground Follow-up Telescope (C-GFT)
Ground-based Wide Angle Camera (GWAC)
Ali (China) and CTIO (Chile) observatories, operational in 2017
36 camera units, 5400 deg²
nm; MV=15 in 10 s → Jianyan Wei talk on GWAC
Chinese Ground Follow-up Telescope (C-GFT)
Robotic 1-m class telescope, Xinglong observatory
FoV = 21x21 arcmin², nm
French Ground Follow-up Telescope (F-GFT)
Robotic 1-m class telescope, San Pedro Martir (Mexico)
FoV = 26x26 arcmin²
Multi-band photometry ( nm, 3 simultaneous bands)
→ Alain Klotz talk
→ David Corre talk
Contribution to the LCOGT network (12x1m+2x2m tel.)
>75% of ECLAIRs-detected GRBs immediately visible by one ground telescope (GFTs+LCOGT)

9. Instruments summary : spectro-temporal coverage

10. To detect GRB on the night side → attitude law : roughly antisolar
The SVOM attitude law
Sun
Night side
SVOM orbit (i ~ 30°)
To detect GRB on the night side → attitude law : roughly antisolar

11. Optimization of the SVOM attitude law
To favor the GRB detection by ECLAIRs
avoidance of the the Sco X1source ( outsite of the ECLAIRs FOV)
avoidance of the Galactic Plane (+/- 10° for the ECLAIRs FOV )
To favor the follow-up and the redshift measurement on ground.
attitude law : roughly antisolar
favor the sky area observable from both Hawaii, Chile and the Canary
To maintain a cold face for the satellite
Offset of 45° with respect to the antisolar direction
CANARY
HAWAII
CHILE
Sco X1

12. One year of observation
Assomption:
65 GRBs/year, obs duration 14 orbits → 1 day
1 ToO per day, obs duration 1 orbit → 40 min
ECLAIRs exposure map
4 Ms in the direction of the galactic poles
500 ks on the galactic plane
One year of observation
Corresponding MXT and VT pointing directions

13. SVOM observation programs
The Core Program: (GRB). Alerts triggered by ECLAIRs and followed by the SVOM instruments. The GRB data products (position, light curve, pre-computed spectra,…) will be made public immediately
The General Program: SVOM will be an open observatory : general program (GP) observations will be awarded by a TAC (a SVOM co-I needs to be part of your proposal). 10% of the time can be spent on low Galactic latitude sources during the nominal mission (up to 50% during the extended mission).
The Target of Opportunity (ToO) program : alerts sent from the ground to the satellite. Initially 1 ToO per day focussed on time domain astrophysics including multi-messengers. ToO program devoted time increases during extended mission.
→ Liping Xin talk on BA organization
→ Xuhui Han talk on General Program organization
→ Jing Wang & Cyril Lachaud talk on ToO organization

14. Distribution of the usefull time of the mission
Nominal mission
Core Program: the GRBs
70 GRBs/year
duration of observation : 14 orbits (tunable)
Targets of Opportunity
ToO nominal : 1/day, programming delay 48h, duration of observation 1 orbit
ToO exceptional : 20/year, programming delay <12h, duration of observation 14 orbits (tunable)
General Program (preplanned observation selected by a TAC)
90% at 5-10° from the B1 attitude law
14 targets max per day
duration of observation 1 orbit minimum
Meudon - June 1, 2015
SVOM

15. Distribution of the useful time
Nominal mission
USEFUL MISSION TIME
Extended mission
USEFUL MISSION TIME
1 ToO per day
10% of the GP outside the B1 law
5 ToO per day
50% of the GP outside the B1 law
MXT meeting – Strasbourg – 17/02/16

16. SVOM sessions
Simulations of the dead time and spectral response for the ECLAIRs detection plan's characterisation, A. Bajat
SVOM trigger presentation, S. Schanne
SVOM GRB rates, the future SVOM GRB sample, F. Daigne
BA organization, L. Xin
TAROT Robotic Telescopes: Techniques and GRB observations from Swift to SVOM, A.Klotz
Estimation of French Ground Follow-up Telescope (F-GFT) photometric redshift accuracy, D.Corre
ToO program organization, J. Wang & C. lachaud
How Swift manages its ToO program, P. O'Brien
General Program organization, X.Han
CORE PROGRAM
ToO PROGRAM
GENERAL PROGRAM

17. SVOM overall planning
LM2C / XICHANG

18. Conclusion
SVOM is designed to study the physics of the GRB phenomenon in all its diversity with good spectral (from visible to MeV) and temporal coverage for the prompt and afterglow emission.
Optimized observation and follow-up strategy is foreseen aiming at redshift determination for a large fraction of SVOM GRBs (>50%)
SVOM is prepared to play an important role in the time domain astrophysics and in the multi-messenger era (follow-up of GW and neutrino alerts)
SVOM and LSST are promised to be great partners in the study of the transient sky in the period
More informations on the science with SVOM with : « Scientific prospects of the SVOM mission » available on the arXiv : (arXiv: )

19. SVOM sessions
Simulations of the dead time and spectral response for the ECLAIRs detection plan's characterisation, A. Bajat
SVOM trigger presentation, S. Schanne
SVOM GRB rates, the future SVOM GRB sample, F. Daigne
BA organization, L. Xin
TAROT Robotic Telescopes: Techniques and GRB observations from Swift to SVOM, A.Klotz
Estimation of French Ground Follow-up Telescope (F-GFT) photometric redshift accuracy, D.Corre
ToO program organization, J. Wang & C. lachaud
How Swift manages its ToO program, P. O'Brien
General Program organization, X.Han
CORE PROGRAM
ToO PROGRAM
GENERAL PROGRAM

21. Core Program, a unique GRB sample
GRB trigger
ECLAIRs
42-80 GRBs/yr
SVOM is sensitive to all classes of GRB (long/short/soft/…)

22. Core Program : a unique GRB sample
Prompt emission
ECLAIRs+GRM
Prompt GRB emission over 3 decades (4 keV-5.5 MeV)
GWAC
prompt visible emission in ~16% of cases
The multi-component spectrum of the Fermi/GBM burst GRB B simulated in ECLAIRs+GRM.

23. Core Program : a unique GRB sample
Afterglow & distance
MXT
X-ray afterglow (>90% of GRBs after a slew)
slew request: GRB/yr VT
Visible and NIR afterglow
+photometric redshift
GWAC
C-GFT/F-GFT
Very large telescopes
The X-ray afterglow of the Swift burst GRB simulated in MXT.
Redshift in ~2/3 of cases

24. Very good 4 keV-5.5 MeV + visible
Core Program : scientific prospects
Swift
Fermi
SVOM
Prompt
Correct
Excellent
8 keV-100 GeV
Very good
4 keV-5.5 MeV + visible
Afterglow
Excellent /
Redshift
~1/3
~2/3
→ Stéphane Schanne talk on the ECLAIRS trigger
→ Frédéric Daigne talk on the SVOM GRB sample

25. ToO program : SVOM And the multi-wavelength alerts
SVOM will be operational during the time domain astronomy era.
Swift and Fermi, if available, will provide external triggers to be followed by SVOM
new instruments, like LSST and SKA, will provide a large number of ToO for the follow-up of transient events detected in their unprecedented survey of the sky.
Nominal ToO, once per day, max delay 48h
Exceptional ToO, once per month, min delay 12h

26. ToO program : SVOM And the multi-messengers alerts.
During the SVOM mission :
GW detectors will reduce the localisation of the GW source (but still tens of square degrees) => EM emission in BH-BH mergers ? BH-NS, NS-NS ?
KM3NeT will be in operation as well as IceCube => source of HE neutrinos ?
HAWC and CTA in operation for VHE Gammas => New transient and GRB physics…
MXT, with multiple tiles, will search for x-ray counterpart of sources located in large error boxes.
For the VHE Gammas (and KM3NeT neutrino tracks), the VT will be able as well to give optical information on the source.
The Multi-Messenger ToO program allows once per month a fast follow-up with a tiling
→ Laura Gosset talk on the tiling with MXT

27. General program : Target Sources and Science Objectives
Accretion / Ejection Physics
Matter in Extreme Conditions of Gravitation & Magnetic Fields and densities
Particle
acceleration
Extragalactic Compact Objects:
AGN and Blazars
Tidal Disruption Events
Ultra Luminous X-ray Sources
Galactic (or LMC/SMC) Compact Objects:
BH/NS X-ray Binaries and Transients
Magnetars, SGRs, Isolated NS and Bright PWN
CVs (White Dwarf binaries) and Active Stars
Galactic Diffuse components:
Cosmic X-Ray Background
Galactic Ridge X-Ray Emission
Peculiar objects and exceptional events:
Solar Emission, Earth albedo, Aurorae, …
Galactic SN, Sgr A* outburst, Magnetars Super-Bursts
→ Christian Motch talk on TDEs studies in the Virgo cluster

28. ToO : multi-messenger
We’ve built a dedicated ToO type (ToO-MM) to follow multi-messenger alerts and scan the large error box region using multiple tiles (thanks to the large f.o.v. of MXT : 1 deg2).
ToO-MM characteristics

29. SVOM and LSST coverage SVOM LSST
Each GRB detected by SVOM in the southern sky will be followed by LSST
Thanks to the antisolar choice, the transient sources detected by LSST could be observed immediately by SVOM