THESEUS (Transient High-Energy Sky and Early Universe Surveyor) is one of the three M7 mission candidates currently in Phase A for assessment and launch opportunity in 2037. The mission is designed to provide unprecedented capabilities for detecting and characterizing X-ray and gamma-ray transients, supporting time-domain and multi-messenger astrophysics. A key instrument on board THESEUS is...
newASTROGAM is a breakthrough mission concept for the study of the non-thermal Universe from space with gamma rays in the energy range from 100 keV to 3 GeV. It is based on an advanced space-proven detector technology, which will achieve unprecedented sensitivity, angular and energy resolution combined with polarimetric capability. Since the MeV gamma-ray energy range is the most...
Gamma-ray and multimessenger astrophysics are frontiers for discovery and uniquely provide access to the extreme processes that sculpt the universe. As a priority theme of the Astro2020 Decadal Survey report: New Messengers New Physics, this science is poised to revolutionize our understanding of the extreme universe. The All-sky Medium Energy Gamma-ray Observatory eXplorer (AMEGO-X) is...
The Compton Spectrometer and Imager (COSI) is an upcoming NASA Small Explorer (SMEX) satellite mission with a planned Falcon 9 launch in 2027. COSI operates as a Compton telescope in the 0.2-5 MeV gamma-ray bandpass, it has an instantaneous field of view of >25%-sky, and it obtains coverage the entire sky every day. COSI provides imaging, spectroscopy, and polarimetry of astrophysical...
The Crystal Eye detector is an all-sky spaceborne gamma-ray monitor intended to cover the energy range between 10 keV - 30 MeV, a region currently lacking of extensive observations and monitoring. To optimize its design and estimate its scientific potential, it is essential to understand the environment where it will operate and how it could affect the observation process. With this aim, we...
The Galactic Annihilation Line Explorer (GALE) mission will address a long-outstanding question in our understanding of the sources of Galactic positrons: whether they are produced by unresolved astrophysical sources or created via diffuse processes, possibly due to dark matter decays and/or interactions. This problem of Galactic positrons that produce 511-keV gamma-ray emission from the...
The astrophysical community is currently focusing on the development of next-generation gamma-ray telescopes designed to detect low-energy photons in the MeV-GeV range, operating in both the Compton and pair conversion regimes. The proposed Advanced Particle-astrophysics Telescope (APT) is a MeV-TeV gamma-ray space-based planned mission aimed at providing an order of magnitude improvement in...
Assessing the performance of a gamma-ray detector in the GeV energy range with an effective 2-pi field of view (FoV) in space is relevant for the design of future missions aimed at the study of the high energy emission of transient events. Such a design offers a significant advantage for detecting short-duration gamma-ray bursts (GRBs), which can be as short as only a fraction of a second....
High-density and high-Z crystals are a key element of most detectors used to observe High Energy (HE) $\gamma-$rays and cosmic rays from space, such as Fermi-LAT and DAMPE. The lattice structure of these materials is usually ignored for all practical purposes, such as instrument calibration or simulation. However, recent studies have shown that this is a rough approximation, since $e^\pm$ and...
The launch of the Imaging X-ray Polarimetry Explorer (IXPE) on December 9, 2021, marked a transformative milestone in high-energy astrophysics, solidifying X-ray polarimetry as the "Holy Grail" of this field. IXPE has not only met but has consistently upheld its pre-launch performance expectations, operating with an impressive duty cycle close to 100%. In particular detectors are compliant...
The CUbesat Solar Polarimeter (CUSP) project is a CubeSat mission planned for a launch in low-Eart orbit and aimed to measure the linear polarization of solar flares in the hard X-ray band by means of a Compton scattering polarimeter. CUSP will allow to study the magnetic reconnection and particle acceleration in the flaring magnetic structures of our star. CUSP is a project in the framework...
COCOA (COmpact COmpton cAmera) is a next-generation, cost-effective gamma-ray telescope designed for astrophysical observations in the MeV energy range. The detector comprises a scatterer volume employing the LiquidO detection technology and an array of scintillating crystals acting as absorber. Surrounding plastic scintillator panels serve as a veto system for charged particles. The...
The eXTP (enhanced X-ray Timing and Polarimetry) mission is a major project of the Chinese Academy of Sciences (CAS), that had a large involvement of Europe, until it was de-scoped to a "China-only" mission in 2024. The scientific payload of the former eXTP included four instruments: SFA (Spectroscopy Focusing Array) and PFA (Polarimetry Focusing Array) - led by China - and LAD (Large Area...
The Lunar Electromagnetic Monitor in X-rays (LEM-X) is a proposed all-sky X-ray observatory to be installed on the surface of the Moon for the rapid identification of high-energy transients and the long-term monitoring of astrophysical sources in the 2 − 50 keV band. Developed within the Earth Moon Mars (EMM) project of the Italian National Recovery and Resilience Plan, LEM-X has been...
