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’

VTVTGRMGRM

ECLAIRSECLAIRS

GFTsGFTsGWACGWAC

MXTMXT

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

ECLAIRs + ECLAIRs + GRM: GRM: Epeak ~ 10-500keVEpeak ~ 10-500keV

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)

T-t0=30 sec

Kann et al 2010

GWAC

VT

Combined optical light curveCombined optical light curve

GFT

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

Prompt dissemination of the GRB parametersPrompt dissemination of the GRB parameters

VHF Network

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

谢 谢！