Marco Feroci

The High Energy Rapid Modular Ensemble of Satellites (HERMES) instrument is a compact X-/gamma-ray spectrometer operating on board the 6U (11 kg) Space Industry–Responsive–Intelligent–Thermal (SpIRIT) CubeSat. The payload is particularly well suited for the observation of cosmic transients such as gamma-ray bursts (GRBs) and bright pulsars thanks to its unique broadband sensitivity from a few keV to a few MeV and temporal resolution down to half a microsecond. We report the detection of the ∼33 ms double-peaked pulse profile of the Crab Pulsar, obtained by considering the canonical Crab ephemerides as provided by the Jodrell Bank catalog. We collected approximately 5.7 × 10 ⁴ photons from 730 s of observations in the 3 keV–2 MeV energy band during a single operation, achieving a 5 σ pulse-profile significance in the 3–11.5 keV energy band with millisecond-scale binning. These results demonstrate that SpIRIT/HERMES can achieve millisecond timing accuracy at high energies and, thanks to its wide field of view and broad energy coverage, has the potential to contribute to GRB monitoring in the near future. Such capabilities were previously the domain of flagship observatories, underscoring the performance of the HERMES instrument even with its compact form factor.

The Wide Field Monitor is one of the 4 state-of-the-art instruments onboard the enhanced X-ray Timing and Polarimetry mission, which will search for and observe neutron stars, magnetars and black holes to study matter under extreme conditions of density, gravity and magnetism. The wide-field cameras of the Wide Field Monitor are based on large-area silicon drift detectors. Such position-sensitive spectroscopic detectors, together with their front-end electronics, must pass a series of functional tests before proceeding with the mass production of the detector assemblies. This paper describes the test system developed to carry out such measurements, as well as reporting the results of the functional tests together with a preliminary characterisation of the performance of the detector assemblies.

Since their first discovery in the late 1960s, gamma-ray bursts have attracted an exponentially growing interest from the international community due to their central role in the most highly debated open questions of the modern research of astronomy, astrophysics, cosmology, and fundamental physics. These range from the intimate nuclear composition of high-density material within the core of ultra-dense neuron stars, to stellar evolution via the collapse of massive stars, the production and propagation of gravitational waves, as well as the exploration of the early universe by unveiling the first stars and galaxies (assessing also their evolution and cosmic re-ionization). GRBs in the past ∼50 years have stimulated the development of cutting-edge technological instruments for observations of high-energy celestial sources from space, leading to the launch and successful operations of many different scientific missions (several of them still in data-taking mode currently). In this review, we provide a brief description of the GRB-dedicated missions from space being designed and developed for the future. The list of these projects, not meant to be exhaustive, shall serve as a reference to interested readers to understand what is likely to come next to lead the further development of GRB research and the associated phenomenology.

The Italian Space Agency plays a key role in the fulfillment of space missions, contributing to the scientific, technological and economic progress in Italy. The agency accomplishes space experiments by collaborating with scientific and industrial entities, supporting them in the realization of new projects able to achieve, over the last two decades, unprecedented results and obtention of fundamental information on the birth and evolution of the universe. The paper describes a selection of X-ray technologies developed by the synergy between the Italian Space Agency and its principal collaborators which contributed to the main scientific results achieved over the years, together with the latest advances addressed to the next astrophysics missions.

We report the AGILE observations of GRB 220101A, which took place at the beginning of 2022 January 1 and was recognized as one of the most energetic gamma-ray bursts (GRBs) ever detected since their discovery. The AGILE satellite acquired interesting data concerning the prompt phase of this burst, providing an overall temporal and spectral description of the event in a wide energy range, from tens of kiloelectronvolts to tens of megaelectronvolts. Dividing the prompt emission into three main intervals, we notice an interesting spectral evolution, featuring a notable hardening of the spectrum in the central part of the burst. The average fluxes encountered in the different time intervals are relatively moderate, with respect to those of other remarkable bursts, and the overall fluence exhibits a quite ordinary value among the GRBs detected by MCAL. However, GRB 220101A is the second farthest event detected by AGILE, and the burst with the highest isotropic equivalent energy of the entire MCAL GRB sample, releasing E _iso = 2.54 × 10⁵⁴ erg and exhibiting an isotropic luminosity of L _iso = 2.34 × 10⁵² erg s⁻¹ (both in the 400 keV–10 MeV energy range). We also analyzed the first 10⁶ s of the afterglow phase, using the publicly available Swift-XRT data, carrying out a theoretical analysis of the afterglow, based on the forward shock model. We notice that GRB 220101A is with high probability surrounded by a wind-like density medium, and that the energy carried by the initial shock shall be a fraction of the total E _iso, presumably near ∼50%.