Astronomy:THESEUS

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Short description: European Space Agency telescope
Mission typeSpace observatory
OperatorEuropean Space Agency
Spacecraft properties
Power115 W[1]
Start of mission
Launch date2037 (proposed)[2]
RocketVega-E[1] (baseline)
Orbital parameters
RegimeLow Earth orbit
Altitude600 km[1]
Inclination5° (equatorial)[1]
Main
DiameterInfrared: 70 cm; Cassegrain type[1]
WavelengthsInfrared, Gamma-rays and X-rays
Cosmic Vision
M-class
← ARIEL
 

Transient High-Energy Sky and Early Universe Surveyor (THESEUS) is a space telescope mission proposal by the European Space Agency that would study gamma-ray bursts and X-rays for investigating the early universe.[1][3] If developed, the mission would investigate star formation rates and metallicity evolution, as well as studying the sources and physics of reionization.

Overview

THESEUS is a mission concept that would monitor transient events in the high-energy Universe across the whole sky and over the entirety of cosmic history. In particular, it expects to make a complete census of gamma-ray bursts (GRBs) from the Universe's first billion years, to help understand the life cycle of the first stars.[4] THESEUS would provide real-time triggers and accurate locations of the sources, which could also be followed up by other space- or ground-based telescopes operating at complementary wavelengths.

The concept was selected in May 2018 as a finalist to become the fifth Medium-class mission (M5) of the Cosmic Vision programme by the European Space Agency (ESA). The other finalist was EnVision, a Venus orbiter. The winner, EnVision, was selected in June 2021 for launch in 2031.[5]

In November 2023, following a new selection process (2022) and a Phase-0 study (2023), THESEUS was selected by ESA for a new 2.5 year Phase-A study as one of the three candidates M7 missions (together with M-Matisse and Plasma Observatory).

The space observatory would study gamma-ray bursts (GRBs) and X-rays and their association with the explosive death of massive stars, supernova shock break-outs, black hole tidal disruption events, and magnetar flares. This can provide fundamental information on the cosmic star formation rate, the number density and properties of low-mass galaxies, the neutral hydrogen fraction, and the escape fraction of ultraviolet photons from galaxies.[1]

Scientific payload

The conceptual payload of THESEUS includes:[1]

  • Soft X-ray Imager (SXI), sensitive to 0.3-6 keV is a set of 4 lobster-eye telescope units, covering a total field of view (FOV) of 1 sr with source location accuracy <1-2 arcmin.
  • InfraRed Telescope (IRT), sensitive to 0.7-1.8 μm is a 0.7 m NIR telescope with 15x15 arcmin FOV, for fast response, with both imaging and moderate spectroscopic capabilities (R~400). Mass: 112.6 kg.
  • X-Gamma ray Imaging Spectrometer (XGIS), sensitive to 2 keV-20 MeV, is a set of coded-mask cameras using monolithic X-gamma ray detectors based on bars of silicon diodes coupled with CsI crystal scintillator, granting a 1.5 sr FOV, a source location accuracy of 5 arcmin in 2-30 keV and an unprecedentedly broad energy band. Mass: 37.3 kg.

See also

References