THE SVOM CONTRIBUTION TO MULTI-MESSENGER ASTROPHYSICS - Cyril Lachaud (APC, Univ. Of Paris) on behalf of the SVOM collaboration
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THE SVOM CONTRIBUTION
TO MULTI-MESSENGER
ASTROPHYSICS
Cyril Lachaud (APC, Univ. Of Paris)
on behalf of the SVOM collaboration
THE SVOM CONSORTIUM
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 2
I. THE MISSION
3
The SVOM « Space-based multi-band astronomical Variable Objects Monitor »
Launch in Dec. 2021, for 3+2 years
mission
ECLAIRs
VT
« The trigger camera »
“The Visible Telescope” Wide-field X and Gamma rays telescope
Narrow-field visible telescope Spectral range : 4 keV – 150 keV
Ritchey Chretien Ф=400mm Localization accuracy < 12arcmin
Localization accuracy < 1arcsec
GRM MXT
“The Gamma-Ray burst Monitor” “The Micro-channel X-ray Telescope”
X-rays and Gamma-rays detectors Narrow-field X-ray telescope
15 keV – 5 MeV Spectral range : 0.2 keV – 10 keV
Localization accuracy < 5° Localization accuracy < 1arcmin
GFT-1 GWAC GFT-2 VHF Alert
« Ground-based
Network
« Ground-based Follow-up « Ground Wide-Angle
Telescope » Cameras » Follow-up Tracking
Telescope »
Ф>1000mm Ф=180mm
Ф>1000mm antennas
… and
more !
4
SVOM INSTRUMENTS: ECLAIRS
ECLAIRs (CNES, IRAP, CEA, APC)
• 40% open fraction
• Detection plane: 1024 cm²
• 6400 CdTe pixels (4x4x1 mm3)
• FoV : 2 sr (zero sensitivity)
• Energy range: 4-150 keV
• Localisation accuracy
SVOM INSTRUMENTS: GRM
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: 15-5000 keV
• Aeff = 190 cm² at peak
• Rough localization accuracy
• Expected rate: ~90 GRBs / year
Will provide Epeak measurements for most ECLAIRs GRBs
Will be able to detect GRBs and transients out of the ECLAIRs FOV (poor localisation
capabilities)
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 6
SVOM INSTRUMENTS: MXT
Micro-channel X-ray Telescope (CNES, CEA, UL, MPE)
• Micro-pores optics (Photonis) with square 40 micron size pores
• pnCCD (MPE) based camera (CEA)
• FoV = 57x57 arcmin²
• Focal length: 1.15 m
• Energy range: 0.2-10 keV
• Aeff = 23 cm² @ 1 keV (central spot)
• Energy resolution: ~80 eV @ 1.5 keV
• Localization accuracy
SVOM INSTRUMENTS: VT
Visible Telescope (XIOMP, NAOC)
• Ritchey-Chretien telescope
• 40 cm Ø, f=9
• FoV = 26x26 arcmin²
• Covering ECLAIRs error box in most cases
• 2 channels: blue (400-650 nm) and red (650-1000 nm)
• 2k * 2k CCD detector each
• Sensitivity MV=22.5 in 300 s
• Will detect ~80% of ECLAIRs GRBs
• Localization accuracy
SVOM OBSERVATION STRATEGY
❖ Launched from Xichang (Sichuan) by an LM-2C rocket in December 2021.
❖ Circular low Earth orbit at 625 km of altitude with an inclination of about 30°
❖ Nearly anti-solar pointing (so-called « B1 » attitude law)
=> Earth in the field of view (65% of duty cycle for ECLAIRs, about 50% for MXT and VT)
❖ Avoidance of the Galactic plane (most of the time) and Sco X-1
❖ Slew capability: 45° in 5 minutes (including arc sec stabilisation)
❖ GRB follow-up during up to 14 orbits (about 1 day)
ECLAIRs exposure map
(65 GRBs/year, 1 ToO per day)
- 4 Ms in the direction of the galactic poles
NIGHT SIDE - 500 ks on the galactic plane
SUN
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 9
VHF NETWORK
Alerts are transmitted to a network of ~40 VHF receivers on Earth
Goal: 65% of the alerts received within 30 s at the French Science Center
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 10VHF ANTENNAS
Kourou Antenna installed on may 2019
2 VHF antennas will be installed in Vietnam :
March 2020 : Ho Chi Min city (managed by Hien Vo Bich physicist at the Vietnamese German University)
End 2020 : Hanoi (managed by the Vietnam National Space Center)
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 11SVOM GROUND BASED INSTRUMENTS
GWACs - Ground based Wide Angle Cameras (NAOC)
• Partly installed in China (near Muztagh Ata) and partly in Chile to optimise
the observation of prompt GRB optical emission
• In China: 40 cameras of 180 mm diameter; total FOV ~6000 sq degrees;
limiting magnitude 16 (V, 10 s)
• In Chile (TBC): 50 cameras of 250 mm diameter; total FOV ~5000 sq degrees;
limiting magnitude 17 (V, 10s)
Will cover instantaneously about 12% of the
ECLAIRs FOV
Self triggering: will be able to catch
autonomously optical transients (e.g.
AT2018cow was discovered at magnitude of
-------------------------- GWAC 14.7, see ATel 11727)
Will scan the entire accessible sky each night
The Chinese GWACs are in commissioning
phase, they participate to 03 LIGO/VIRGO run.
T-T0=30 sec
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 12SVOM GROUND BASED INSTRUMENTS
Chinese Ground Follow-up Telescope (C-GFT |
2020)
Robotic 1.2 m class telescope, Jilin observatory
FoV = 21x21 arcmin², 400-950 nm + primary
focus 1.5x1.5 deg² FOV
French Ground Follow-up Telescope (F-GFT |
2020/2021)
Robotic 1.3 m class telescope, San Pedro Martir
(Mexico)
FoV = 26x26 arcmin²
Multi-band photometry (400-1700 nm, 3
simultaneous bands, allows for photo-z)
Contribution to the LCOGT network
(12x1m+2x2m tel.)
>75% of ECLAIRs-detected GRBs immediately
visible by one ground telescope (GFTs+LCOGT)
Courtesy D. Corre
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 13SVOM MULTI-λ COVERAGE
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 14II. THE EXPECTED SVOM GRB SAMPLE 15
CORE PROGRAM : A COMPLETE GRB SAMPLE
Original catalogs
GRB trigger Simulation in ECLAIRs
ECLAIRs
42-80 GRBs/yr
ECLAIRs is sensitive to all classes of GRBs
Detection probability by ECLAIRs
Classical long GRBs
(simulations by S. Antier)
Soft GRBs (XRR, XRF)
Short GRBs
(but with a moderate efficiency) 16CORE PROGRAM : A COMPLETE GRB SAMPLE
The multi-component spectrum of the Fermi/
Prompt emission GBM burst GRB 100724B simulated in
ECLAIRs+GRM.
ECLAIRs+GRM
Prompt GRB emission
over 3 decades
(4 keV-5.5 MeV)
GWAC
prompt visible emission
in ~16% of cases
ECLAIRs+GRM can measure the prompt
spectrum over 3 decades in energy
GWAC will add a constraint on the
associated prompt optical emission in a
good fraction of cases.
17CORE PROGRAM : A COMPLETE GRB SAMPLE
Slew request
36-72 GRB/yr
18CORE PROGRAM : A COMPLETE GRB SAMPLE
Afterglow
MXT
X-ray afterglow
The X-ray afterglow of the Swift burst GRB
091020 simulated in MXT.
(Bernardini et al. 2017)
MXT can detect and localize the X-ray afterglow in >90% of GRBs after a slew.
19CORE PROGRAM : A COMPLETE GRB SAMPLE
VT, C-GFT and F-GFT will detect,
localize and characterize the V-NIR
Afterglow & distance
afterglows (lightcurve+photo-z).
Early observation by large telescopes
are favored by SVOM’s pointing
strategy.
VT
Redshift measurement is expected in
~2/3 of cases
GWAC
Very large
C-GFT/F-GFT
telescopes
Redshift in ~2/3 of cases 20CORE PROGRAM : A COMPLETE GRB SAMPLE
A unique sample of 30-40 GRB/yr with
- prompt emission over 3 decades (+ optical flux/limit: 16%)
- X-ray and V/NIR afterglow
- redshift Swift Fermi SVOM
Prompt Poor Excellent Very Good
8 keV -100 GeV 4 keV - 5 MeV
Afterglow Excellent > 100 MeV for LAT Excellent
GRBs
Redshift ~1/3 Low fraction ~2/3
Physical mechanisms at work in GRBs
Nature of GRB progenitors and central engines
Acceleration & composition of the relativistic ejecta
Diversity of GRBs: event continuum following the collapse of a massive star
Low-luminosity GRBs / X-ray rich GRBs / X-ray Flashes and their afterglow
GRB/SN connection
Short GRBs and the merger model
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 21III. THE OBSERVATIONS PROGRAMS
22SVOM OBSERVATION PROGRAMS
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 Core Program (GRB). GRB data products (position, light curve, pre-computed
spectra will be made public immediately)
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.
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 23THE SVOM ToO PROGRAM
Target of Opportunity program
Transient/event detected
by other facilities => send commands to the satellite
to trigger observations from the
Cosmic rays AUGER
JEM-Euso
LHASSO
ground
KM3NeT
Neutrinos
IceCube IceCube-Gen2
HESS CTA
Fermi
γ-rays Wukong
INTEGRAL
POLAR
HXMT
NuSTAR
X-rays
Spektr-RG
XMM-Newton Athena
Multi SVOM
wavelength Swift
HST
E-ELT
Visible and TMT
near infrared LSST
VLT
Euclid
Infrared JWST
ALMA
SKA
Radio waves
FAST
LOFAR
IndiGO
Gravitational KAGRA
waves Advanced Virgo
Advanced LIGO
Year 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030
Complex operations at system level
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 24ToO-NOM
ToO-NOM is the nominal ToO which covers the basic needs for efficient
transient follow-up. Scientific target :
- GRB revisit
- Pre-planned observations
through a GP proposal waiting
for a known source to flare
(AGN,…)
- New transient (LSST, CTA, …)
Main characteristics :
Jonker et al.
Frequency : 1/day
Standard delay : < 48h
Duration : 1 orbit (or more)
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 25ToO-NOM
ToO-NOM is the nominal ToO which covers the basic needs for efficient
transient follow-up. Scientific target :
- GRB revisit
e n n-a s
Pre-planned observations
F a n t
h e V H , t hthrough
e a GP proposal waiting
Fo r t m en t for aw ill
known source to flare
n a g e i s ts
ma e physic (AGN,…) i g g er
m e s y to tr
ie tn a s ib i li t - New transient (LSST, CTA, …)
h
V p o s r w it
ve th e / y e a is
h a - N O M n a ly s
O a
3 To for data Main characteristics :
Jonker et al.
p p o r t Frequency : 1/day
s u
Standard delay : < 48h
Duration : 1 orbit (or more)
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 26ToO-EX
ToO-EX is the exceptional ToO which covers the needs for a fast ToO-
NOM in case of an exceptional astrophysical event we want to observe
rapidly.
Main characteristics :
Jonker et al. Frequency : 1/month
Standard delay : < 12h
Duration : 7-14 orbits
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 27ToO-MM
ToO-MM is the ToO dedicated to EM counterpart search in response to a
multi-messenger alert. What differs from the ToO-NOM and ToO-EX is the
unknown position of the source within a large error box…
Main characteristics :
Frequency : 1/week
Standard delay : < 12h
Duration : ~14 orbits
Tiling Operations
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 28TILING STRATEGY : MXT
To follow multi-messenger alerts using tiles, Swift/
XRT is better than SVOM/MXT in terms of
sensitivity and localization accuracy.
But MXT is very competitive to rapidly cover large
error boxes with only a slightly reduced sensitivity
thanks to its large field of view (1 deg2).
Typical scenario: 5 tiles/orbit – 15 orbits (~ 1 day)
Swift/XRT f.o.v
SVOM/MXT f.o.v
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 29TILES SEQUENCING SIMULATIONS: MXT
Simulation of a ToO-MM request for GW170814
Scenario GW170814
Nb. tiles 230
RA min (°) 34.4
RA max (°) 53.4
Dec min (°) -54.3
Dec max (°) -7.8
LH total (%) 90.0
LH 75 (%) 66.0
First
100
(10°x10°)
tiles
Likelihood
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 30IV. GW170817/GRB170817A
31ECLAIRS + GRM GRB DETECTION ?
Simulation of the event GRB170817A + CXB θ
Parameters from Fermi-GBM (public GCN 2017/8/17 20:00 TU)
SNR
ECLAIRs
Incidence angle with respect to ECLAIRs axis (θ °)
➔ Up to 35°: ECLAIRs triggers + slew + alert to the ground
➔ Up to 50°: GRM triggers + alert (rough localisation)
GRM
14KILONOVA DETECTION WITH VT + GFT ?
Simulation of the kilonova as seen by VT in 300s at peak magnitude
➔ VT and GFTs have the capacity to detect the kilonova since T0+2h,
and can follow it during 10 days.
14SVOM WHITE PAPER
(Much) More informations in the
SVOM white paper :
Wei, Cordier et al.
« Scientific prospects of the
SVOM mission »
arXiv:1610.06892
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 34CONCLUSION
2022+: more GW/HE neutrino/… alerts with better localization.
SVOM’s set of instruments is well adapted to the search of electromagnetic counterparts
to GW/HE neutrino events.
Gamma-rays: ECLAIRs and GRM have a large field of view (~45% of the sky) and a good
sensitivity to interesting classes of GRBs (short GRBs, low-luminosity GRBs, …).
In case of a detection with ECLAIRs or 3 GRDs: localization (10’ → a few °).
X-rays: MXT requires a slew + a tiling strategy for large error boxes.
Can cover ~100 deg2. In case of detection: localization (1000 deg2) but with mlim ~17.
C-/F-GFT can contribute to the photometric follow-up as soon as an
electromagnetic counterpart is detected with a localization < 30 arcmin.
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 35SVOM STM PICTURES (COURTESY SECM & CNES)
Thermal Vacuum testing INTEGRATED PAYLOAD
MXT STM
ECLAIRs coded mask
ECLAIRs STM
Cyril Lachaud - SVOM & Multi-messenger Astrophysics - TMEX - Quy Nhon 10/01/2020 36You can also read
