Space Multi-bandpace Multi-band Variableariable Objectsbjects Monitoronitor
-----A Chinese-French Mission for GRBs-----A Chinese-French Mission for GRBs
WEI Jianyan NAOC, Beijing
Jacques PAUL IRFU-SAp, Saclay and APC, Paris
ZHANG Shuangnan IHEP, Beijing
Stephane BASA LAM, Marseille
On behalf of the joint SVOM team
Liverpool, June 18, 2012
GRB physicsGRB physics Acceleration and nature of the relativistic jetAcceleration and nature of the relativistic jetRadiation processesRadiation processesThe early afterglow and the reverse shockThe early afterglow and the reverse shock
The GRB-supernova connectionThe GRB-supernova connectionShort GRB progenitorsShort GRB progenitors
GRB progenitorsGRB progenitors
FundamentalFundamental Origin of high-energy cosmic raysOrigin of high-energy cosmic raysProbing Lorentz invarianceProbing Lorentz invarianceShort GRBs and gravitational wavesShort GRBs and gravitational waves
physicsphysics
CosmologyCosmology
Tracing star formationTracing star formationRe-ionization of the universeRe-ionization of the universeCosmological parametersCosmological parameters
Cosmological lighthouses (absorption systems)Cosmological lighthouses (absorption systems)Host galaxiesHost galaxies
Scientific rationale of a new GRB mission Scientific rationale of a new GRB mission
GRB phenomenonGRB phenomenon Diversity and unity of GRBsDiversity and unity of GRBsGRB phenomenonGRB phenomenon Diversity and unity of GRBsDiversity and unity of GRBs
GRB physicsGRB physics Acceleration and nature of the relativistic jetAcceleration and nature of the relativistic jetRadiation processesRadiation processesThe early afterglow and the reverse shockThe early afterglow and the reverse shock
The GRB-supernova connectionThe GRB-supernova connectionShort GRB progenitorsShort GRB progenitors
GRB progenitorsGRB progenitors
CosmologyCosmology
Tracing star formationTracing star formationRe-ionization of the universeRe-ionization of the universeCosmological parametersCosmological parameters
Cosmological lighthouses (absorption systems)Cosmological lighthouses (absorption systems)Host galaxiesHost galaxies
FundamentalFundamental Origin of high-energy cosmic raysOrigin of high-energy cosmic raysProbing Lorentz invarianceProbing Lorentz invarianceShort GRBs and gravitational wavesShort GRBs and gravitational waves
physicsphysics
Permit the detection of all know types of GRBs (>200), with a special Permit the detection of all know types of GRBs (>200), with a special care on high-z GRBs and low-z sub-luminous GRBscare on high-z GRBs and low-z sub-luminous GRBs
Scientific requirements on SVOMScientific requirements on SVOM
Provide fast, reliable and accurate GRB positionsProvide fast, reliable and accurate GRB positions
Measure the broadband spectral shape of the prompt emissionMeasure the broadband spectral shape of the prompt emission(from visible to MeV)(from visible to MeV)
Measure the temporal properties of the prompt emissionMeasure the temporal properties of the prompt emission
Quickly identify the afterglows of detected GRBs, including those that Quickly identify the afterglows of detected GRBs, including those that are highly redshifted (z>6)are highly redshifted (z>6)
Quickly provide (sub-) arcsec positions of detected afterglowsQuickly provide (sub-) arcsec positions of detected afterglows
Quickly provide redshift indicators of detected GRBsQuickly provide redshift indicators of detected GRBs
ECLAIRsECLAIRs, the X-ray and soft gamma-ray trigger camera, the X-ray and soft gamma-ray trigger camera 4-250KeV 2sr (90*90 deg)
GRMGRM, the gamma-ray spectro-photometer, the gamma-ray spectro-photometer
50KeV-5MeV 2sr
VTVT, the visible telescope, the visible telescope 400-650nm, 650-950nm 26’26’
MXTMXT, the micro-channel soft X-ray telescope, the micro-channel soft X-ray telescope 0.3-5KeV 65’65’
GWACGWAC, an array of ground wide angle cameras, an array of ground wide angle cameras 450-900nm 2sr
ProposProposed scientific instrumentsed scientific instruments
C-GFTC-GFT, the Chinese ground follow-up telescope, the Chinese ground follow-up telescope 400-1000nm? 25’25’
F-GFTF-GFT, the French ground follow-up telescope, the French ground follow-up telescope 400-1700nm 30’30’
Eclairs: the triggerEclairs: the trigger
Field of viewField of view: 2 sr: 2 sr
200 module200 modules of 32 CdTes of 32 CdTe
detectors (4 mm detectors (4 mm × 4 mm)× 4 mm)
Useful areaUseful area: 1024 cm: 1024 cm22
Spectral domainSpectral domain: : 4 keV to 300 keV4 keV to 300 keV
2-D coded mask (30% transparency)2-D coded mask (30% transparency)
Passive shield toPassive shield to block X-ray background block X-ray background
ECLAIRs: the trigger cameraECLAIRs: the trigger camera
Main design objectiveMain design objective
A low energy threshold in the X-ray domain
Simulated sensitivitySimulated sensitivity
3.5 keV
Energy (keV)10 40 605020 30
Cou
nts
100
200
300
0
ECLAIRs expected to be more sensitive than SWIFT
(BAT) for GRBs whose peak energy is < 20 keV
ECLAIRs – Anticipated performancesECLAIRs – Anticipated performances
Simulated redshift distribution of long GRBs to be detected by ECLAIRsSimulated redshift distribution of long GRBs to be detected by ECLAIRs
Nearly 10-20% of ECLAIRs GRBs could be situated at high redshift (z > 6)Nearly 10-20% of ECLAIRs GRBs could be situated at high redshift (z > 6)
0 6 1082 40
Redshift z
20
40
60
80
100
Fra
ctio
n >
z (
%)
ECLAIRs
SWIFT (bright) SWIFT
DATA (SWIFT)
GRM: the Gamma-Ray MonitorGRM: the Gamma-Ray Monitor
Scintillation (phoswich) detectorScintillation (phoswich) detector
Useful areaUseful area : : 280 cm280 cm22 per module per module
NaI (10 mm thick) + CsI (40 mm thick)NaI (10 mm thick) + CsI (40 mm thick)
Spectral DomainSpectral Domain :: 5050 keV to 5 MeV keV to 5 MeV
Measurement ofMeasurement of EEpeakpeak (( up to up to ~ 500 keV~ 500 keV ))
FoV : 2 sr2 sr
2 modules2 modules
MXT: to provide the accurate positioningMXT: to provide the accurate positioning
Spectral domainSpectral domain: : 0.0.33 keV to keV to 55 keV keV
Detected GRBs to be localized with an error ~ 30 arc sec
Micro-Channel optics
CCD camera passively cooledCCD camera passively cooled
Field of viewField of view: : 6655 arc min arc min × 6× 65 arc min5 arc min
Useful areaUseful area: : 5252 cm cm22 at at 11 keV keV
Sensitivity: Comparison with Swift/XRTSensitivity: Comparison with Swift/XRT
MXT can detect ~90% of the afterglowsMXT can detect ~90% of the afterglows
VTVT :: the Visible Telescopethe Visible Telescope
Aperture size Aperture size :: 454500 mm mm
Field of ViewField of View :: 226 6 arc min arc min × 2× 26 arc min6 arc minFocal lengthFocal length :: 3600mm3600mm
BandsBands :: 440000-6-65500 nm & nm & 650-950650-950 nmnm
Modified R-C optical designModified R-C optical design
Afterglow emission detection down to MAfterglow emission detection down to MV V ~ 23 (300 s exposure~ 23 (300 s exposure) )
12 14 16 18 20 22 24Magnitude at 1000 seconds
0.2Cum
ulat
ive
prob
abili
ty
0.0
0.4
0.6
0.8
1.0
VT: the visible telescope VT: the visible telescope
The intrinsic cumulative GRB apparent optical afterglow distributionThe intrinsic cumulative GRB apparent optical afterglow distribution
To detect ~ 80% of the observed GRBs
Akerlof & Swan, ApJ 671, 1868, 2007
UVOT-UVOT-SWIFTSWIFT
VT-SVOMVT-SVOM
Spectral bandSpectral band Field of Field of ViewView
Allocation Allocation AccuracyAccuracy
GRBs/yrGRBs/yr
(Dect. Rate)(Dect. Rate)
GRMGRM 50keV-5MeV50keV-5MeV 2 sr2 sr Not applicableNot applicable ~100~100
ECLAIRsECLAIRs 4-250 keV4-250 keV 2 sr2 sr 10 arcmin10 arcmin ~80~80
MXTMXT 0.3-5 keV0.3-5 keV 6565 65 65 arcminarcmin 30 arcsec30 arcsec ~90%~90%
VTVT400-650 nm400-650 nm
650-950 nm650-950 nm
26 26 26 26
arcsecarcsec1 arcsec1 arcsec ~80%~80%
Space instruments performancesSpace instruments performances
Parameters of GWACParameters of GWAC
CamerasCameras : : 7272
DiameterDiameter : : 180mm180mm
Focal LengthFocal Length : : 213mm213mm
WavelengthWavelength : : 450450 -- 900nm900nm
Total FoVTotal FoV : : 9000Sq.deg9000Sq.deg
Limiting MagLimiting Mag : : 16.5V16.5V (( 55 ,, 10sec10sec
))
Prompt optical emission detection down to MPrompt optical emission detection down to MV V ~ 16.5 (10 s exposure) ~ 16.5 (10 s exposure)
SunSun
SunSun
SunSun Night sideNight side
Night sideNight side
Night sideNight side
Pointing strategy: anti solarPointing strategy: anti solar
SVOM orbit (i SVOM orbit (i ~ 30°)~ 30°)
of large ground based telescopes all located at tropical latitudesof large ground based telescopes all located at tropical latitudes
About 75% of the GRBs detected by SVOM to be well above the horizonAbout 75% of the GRBs detected by SVOM to be well above the horizon
GRB observation strategyGRB observation strategy
GroundGround
SpaceSpace
GWACGWAC
GFTs GFTs (g, r, i, J, H)(g, r, i, J, H)
TT00 +1 min +1 min
1-2 m robotic telescopes1-2 m robotic telescopes
GRB trigger provided by GRB trigger provided by ECLAIRsECLAIRs at time T at time T00
VTVT (V & R band photometry) (V & R band photometry)MXTMXT (Soft X-ray photometry) (Soft X-ray photometry)
TT00 + 5 min + 5 min
Multi messenger follow-upMulti messenger follow-up
Multi-wavelength capabilities of SVOM Multi-wavelength capabilities of SVOM
102 103 104 105101-5 0
1022
1020
1016
1018
1014
1015
1014
Time (s)
Log. scale
Time (m)
Lin. scale
Fre
qu
ency
(H
z)F
req
uen
cy (
Hz)
Space
Ground
Slew
GRM
ECLAIRs MXT
VT
GWAC
F-GFT
C-GFT
SVOM compared with SwiftSVOM compared with Swift
Prompt emission measurement More sensitive below 20keV (to 4keV)More sensitive below 20keV (to 4keV) Better Epeak measurement capabilityBetter Epeak measurement capability Prompt optical emission Prompt optical emission
Afterglow emission measurement 10 times more sensitive in the visible, additional 650-950 nm band 10 times more sensitive in the visible, additional 650-950 nm band
Ground follow-up observation Two dedicated 1meter telescopes with NIR dectectorTwo dedicated 1meter telescopes with NIR dectector GRBs more easily scrutinized by the largest telescopesGRBs more easily scrutinized by the largest telescopes
Hunting for high-z GRBsHunting for high-z GRBs
SVOM is going to provide redshift indicators to GCN Eclairs + GRM: pseudo redshiftEclairs + GRM: pseudo redshift VT: redshift indicator: z<4.2, 4<z<6.0, z>6.0 or “dark”VT: redshift indicator: z<4.2, 4<z<6.0, z>6.0 or “dark” GFTs: photometric redshiftGFTs: photometric redshift
Ground near Infrared telescopes are encouraged to point
promptly to the GRBs which are detected by MXT in X-ray,
but not by VT ! (~10 per year)
2005 2005
Status of the SVOM mission Status of the SVOM mission
Sino-FrenchSino-French discussions (CNES-CNSA) on a discussions (CNES-CNSA) on a mini satellite mini satellite missionmission
2006 2006 SVOMSVOM Phase 0 Phase 0 kick-off meeting (March, Toulouse)kick-off meeting (March, Toulouse)
ScientificScientific discussions on the discussions on the SVOM SVOM mission for GRB studiesmission for GRB studies
SVOM phase 0 reviewSVOM phase 0 review (Sept., Shanghai) – (Sept., Shanghai) – No critical issueNo critical issue
CNSA/CNES MoU CNSA/CNES MoU signed during the signed during the PresidentPresident visit (Oct., Beijing) visit (Oct., Beijing)
2007 2007 SVOMSVOM Phase A Phase A kick-off meetingkick-off meeting (March, Xi’an) (March, Xi’an)
SVOM mission SVOM mission approved approved by CNES SPCby CNES SPC (April, Paris)(April, Paris)
SVOM Phase A SVOM Phase A reviewreview meeting meeting ((OctOct., ., BeijingBeijing))20020088
20020099 SVOMSVOM proved by CNES France proved by CNES France
SVOMSVOM launch at Kulu, launch at Kulu, the only mission to deliver GRB localization the only mission to deliver GRB localization (?)(?)
SVOMSVOM funded by CNSA China funded by CNSA China20201010
20201616
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