THE TRANSIENT HIGH-ENERGY SKY AND EARLY UNIVERSE SURVEYOR

The Transient High-Energy Sky and Early Universe Surveyor (THESEUS) is a mission concept developed in the last years by a large European consortium and currently under study by the European Space Agency (ESA) as one of the three candidates for next M5 mission (launch in 2032). THESEUS aims at exploiting high-redshift GRBs for getting unique clues to the early Universe and, being an unprecedentedly powerful machine for the detection, accurate location (down to ∼arcsec) and redshift determination of all types of GRBs (long, short, high-z, under-luminous, ultra-long) and many other classes of transient sources and phenomena, at providing a substantial contribution to multi-messenger time-domain astrophysics. Under these respects, THESEUS will show a strong synergy with the large observing facilities of the future, like E-ELT, TMT, SKA, CTA, ATHENA, in the electromagnetic domain, as well as with next-generation gravitational-waves and neutrino detectors, thus greatly enhancing their scientific return

ESA THESEUS and cataclysmic variables

The capabilities of the considered space mission THESEUS for investigation of cataclysmic variables (CVs) are discussed.Transient High-Energy Sky and Early Universe Surveyor (THESEUS) is a space mission proposal accepted by the European Space Agency for a phase A study that would study gamma-ray bursts and X-rays for investigating the early universe and for the multimessenger astrophysics. It involves a Lobster-Eye X-ray telescope as well. The THESEUS and SMILE international consortia involve the Czech Technical University in Prague and the Czech teams are expected to contribute to the project, mainly to the X-ray telescope and related science and software

Synergies of THESEUS with the large facilities of the '30s and GO opportunities

The proposed THESEUS mission will vastly expand the capabilities to monitor the high-energy sky. It will specifically exploit large samples of gamma-ray bursts to probe the early universe back to the first generation of stars, and to advance multimessenger astrophysics by detecting and localizing the counterparts of gravitational waves and cosmic neutrino sources. The combination and coordination of these activities with multi-wavelength, multi-messenger facilities expected to be operating in the 2030s will open new avenues of exploration in many areas of astrophysics, cosmology and fundamental physics, thus adding considerable strength to the overall scientific impact of THESEUS and these facilities.We discuss here a number of these powerful synergies and guest observer opportunities.</p

Time domain astronomy with the THESEUS satellite

THESEUS is a medium size space mission of the European Space Agency, currently under evaluation for a possible launch in 2032. Its main objectives are to investigate the early Universe through the observation of gamma-ray bursts and to study the gravitational waves electromagnetic counterparts and neutrino events. On the other hand, its instruments, which include a wide field of view X-ray (0.3-5 keV) telescope based on lobster-eye focussing optics and a gamma-ray spectrometer with imaging capabilities in the 2-150 keV range, are also ideal for carrying out unprecedented studies in time domain astrophysics. In addition, the presence onboard of a 70 cm near infrared telescope will allow simultaneous multiwavelegth studies. Here we present the THESEUS capabilities for studying the time variability of different classes of sources in parallel to, and without affecting, the gamma-ray bursts hunt