SVOM Instruments
ECLAIRs telescope
The ECLAIRs telescope plays a key role onboard SVOM by autonomously detecting Gamma-ray bursts (GRBs) in near real time in the X-/Gamma-ray energy range, and then by quickly providing their position in the sky.
The ECLAIRs consortium is made up of several French labs: IRAP, IRFU and APC. The ECLAIRs telescope is under the CNES supervision.
Gamma Ray Monitor
The gamma ray monitor (GRM) consists of a set of three detectors (GRD Gamma-Ray Detectors) operating in the 15 keV-5 MeV energy range and covering a field of view of 2.6 steradians. These modules are responsible for measuring the spectrum and the variation of the gamma emission during a burst. Each detector consists of a scintillation crystal of sodium iodide (NaI) with a surface of 200 cm2 and a thickness of 1.5 cm attached to a photomultiplier tube. In such device, the incident gamma photon interacts with the scintillator material and the deposited energy is transformed into a bluish light, detected and amplified by the photomultiplier tube.
Microchannel X-ray Telescope (MXT)
In response to alerts transmitted by the ECLAIRs, the Microchannel X-ray Telescope (MXT) will observe gamme ray bursts (GRBs) in the soft X-ray range (energy between 0.2 and 10 KeV), from the very beginning of their afterglow emission. The MXT is being developed in France by CNES and CEA/Irfu, in close collaboration with the University of Leicester in the United Kingdom and the Max-Planck Institute für extraterrestische Physik in Germany.
Visible Telescope
The VT telescope (Visible Telescope) is a dedicated optical tracking telescope, onboard the SVOM satellite. Its main purpose is to detect and observe the emission in visible light, produced immediately after a gamma burst. In less than 10 minutes after the alert given by the ECLAIRS camera and using the refined position provided by the MXT instrument, this instrument is able to reconstruct the position of the gamma burst with an accuracy of a few seconds of arc. The VT is expected to detect and locate about 60 gamma bursts per year.
Ground-based Wide Angle Camera (GWAC)
The main science objective of the Ground-based Wide Angle Camera (GWAC) is to observe in the visible range (between 500 and 850 nm) from the ground, the prompt emission of some of the gamma-ray bursts detected by the camera ECLAIRs.
The instrument consists of 10 mountings, each carrying 4 cameras 18 cm in diameter, covering a field of view of about 5000 degrees2, roughly half of the field of view of the ECLAIRs telescope.
Each of the 40 cameras is equipped with a 4096 × 4096 E2V CCD operating in the 0.5 to 0.85 ?m wavelength band with a field of view (FoV) of 150 deg². GWAC provides source locations up to a visible magnitude mv = 16 with an accuracy of 11 arcsec (for a 10 s exposure).
F-GFT Ground tracking telescope (France)
The French ground follow-up telescope, F-GFT (Colibri), is a new telescope that precisely meets the mission’s requirements, namely a system with very good sensitivity (1.3 meters in diameter), remarkable responsiveness (on the target in less than 20 seconds), a wide field of view (26 arcminutes), and a panchromatic vision (three simultaneous cameras: two in visible light and one in infrared). To ensure its effectiveness, it must also be capable of observing automatically, without any human intervention.
The F-GFT is thus capable of detecting a burst less than 5 minutes after receiving an alert from SVOM, up to a magnitude of 22.0 in R_AB and 20.5 in J_AB. With these observations, it can provide a photometric redshift with better than 10% precision in a redshift range between 3.5 and 7.5, while identifying the closest (z<3.5) and farthest (>7.5).
C-GFT Ground Tracking Telescope (China)
The Chinese Ground Tracking Telescope (C-GFT) is based on an existing 1 m telescope located at the Jilin Observatory in China, which is a f / 8 Ritchey-Christian system, allowing rapid repointing through a altazimutal mount. It will be upgraded with a dichroic mirror system, 3 SDSS filter channels (g, r and i), a robotic control system and a real-time data and communication system.
the Alert network
The nerve centre of the SVOM mission’s scientific strategy, the French-designed alert network enables information to be transmitted rapidly and at any time between the satellite and Earth. In order to gather the information needed to determine the distance of the burst, it is essential to complete the multi-wavelength tracking begun in space.