The THESEUS space mission: science goals, requirements and mission concept

Full list of authors: Amati, L.; O'Brien, P. T.; Götz, D.; Bozzo, E.; Santangelo, A.; Tanvir, N. ; Frontera, F.; Mereghetti, S.; Osborne, J. P.; Blain, A.; Basa, S.; Branchesi, M.; Burderi, L.; Caballero-García, M.; Castro-Tirado, A. J.; Christensen, L.; Ciolfi, R.; De Rosa, A.; Doroshenko, V.; Ferrara, A.; Ghirlanda, G.; Hanlon, L.; Heddermann, P.; Hutchinson, I.; Labanti, C.; Le Floch, E.; Lerman, H.; Paltani, S.; Reglero, V.; Rezzolla, L.; Rosati, P.; Salvaterra, R.; Stratta, G.; Tenzer, C.; Theseus Consortium.--This Open Access article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
THESEUS, one of the two space mission concepts being studied by ESA as candidates for next M5 mission within its Comsic Vision programme, aims at fully exploiting Gamma-Ray Bursts (GRB) to solve key questions about the early Universe, as well as becoming a cornerstone of multi-messenger and time-domain astrophysics. By investigating the first billion years of the Universe through high-redshift GRBs, THESEUS will shed light on the main open issues in modern cosmology, such as the population of primordial low mass and luminosity galaxies, sources and evolution of cosmic re-ionization, SFR and metallicity evolution up to the “cosmic dawn” and across Pop-III stars. At the same time, the mission will provide a substantial advancement of multi-messenger and time-domain astrophysics by enabling the identification, accurate localisation and study of electromagnetic counterparts to sources of gravitational waves and neutrinos, which will be routinely detected in the late ‘20s and early ‘30s by the second and third generation Gravitational Wave (GW) interferometers and future neutrino detectors, as well as of all kinds of GRBs and most classes of other X/gamma-ray transient sources. Under all these respects, THESEUS will provide great synergies with future large observing facilities in the multi-messenger domain. A Guest Observer programme, comprising Target of Opportunity (ToO) observations, will expand the science return of the mission, to include, e.g., solar system minor bodies, exoplanets, and AGN. © 2021, The Author(s).
The authors, on behalf of the entire THESEUS consortium, are grateful to the ESA-appointed THESEUS Study Scientist Matteo Guainazzi, as well as the entire ESA Study Team for all their work and support across the mission assessment phase (2018-2021). Authors from the Italian National Institute of Astrophysics (INAF) are grateful for the support received through the agreement ASI-INAF n. 2n. 2018-29-HH.0. Open access funding provided by Istituto Nazionale di Astrofisica within the CRUI-CARE Agreement.
With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.