The origin of the elements is a fascinating question that scientists have been trying to answer for the last seven decades. The formation of light elements in the primordial universe and heavier elements in astrophysical sources occurs through nuclear reactions. We can say that nuclear processes are responsible for the production of energy and synthesis of elements in the various astrophysical sites. Thus, nuclear reactions have a determining role in the existence and evolution of several astrophysical environments, from the Sun to the spectacular explosions of supernovae. Nuclear astrophysics attempts to address the most basic and important questions of our existence and future. There are still many issues that are unresolved such as, how stars and our Galaxy have formed and how they evolve, how and where are the heaviest elements made, what is the abundance of nuclei in the universe and what is the nucleosynthesis output of the various production processes and why the amount of lithium-7 observed is less than predicted. In this paper, we review our current understanding of the different astrophysical nuclear processes leading to the formation of chemical elements and pay particular attention to the formation of heavy elements occurring during high-energy astrophysical events. Thanks to the recent multi-messenger observation of a binary neutron star merger, which also confirmed production of heavy elements, explosive scenarios such as short gamma-ray bursts and the following kilonovae are now strongly supported as nucleosynthesis sites.

The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a 40-m class radio telescope under construction that has been designed to measure the large-angular-scale intensity of Hi emission at 980-1260 MHz and hence to constrain dark energy parameters. A large focal plane array comprising of 1.7-metre diameter, 4.3-metre length corrugated feed horns is required in order to optimally illuminate the telescope. Additionally, very clean beams with low sidelobes across a broad frequency range are required, in order to facilitate the separation of the faint Hi emission from bright Galactic foreground emission. Using novel construction methods,

Context. Observations of the redshifted 21-cm line of neutral hydrogen (Hi) are a new and powerful window of observation that offers us the possibility to map the spatial distribution of cosmic Hi and learn about cosmology. Baryon Acoustic Oscillations from Integrated Neutral Gas Observations (BINGO) is a new unique radio telescope designed to be one of the first to probe baryon acoustic oscillations (BAO) at radio frequencies.Aims. BINGO has two science goals: cosmology and astrophysics. Cosmology is the main science goal and the driver for BINGO's design and strategy. The key of BINGO is to detect the low redshift BAO to put strong constraints on the dark sector models and test the ΛCDM (cold dark matter) model. Given the versatility of the BINGO telescope, a secondary goal is astrophysics, where BINGO can help discover and study fast radio bursts (FRB) and other transients, as well as study Galactic and extragalactic science. In this paper, we introduce the latest progress of the BINGO project, its science goals, describing the scientific potential of the project for each goal and the new developments obtained by the collaboration. Methods. BINGO is a single dish transit telescope that will measure the BAO at low-z by making a 3D map of the Hi distribution through the technique of intensity mapping over a large area of the sky. In order to achieve the project's goals, a science strategy and a specific pipeline for cleaning and analyzing the produced maps and mock maps was developed by the BINGO team, which we generally summarize here. Results. We introduce the BINGO project and its science goals and give a general summary of recent developments in construction, science potential, and pipeline development obtained by the BINGO collaboration in the past few years. We show that BINGO will be able to obtain competitive constraints for the dark sector. It also has the potential to discover several FRBs in the southern hemisphere. The capacity of BINGO in obtaining information from 21-cm is also tested in the pipeline introduced here. Following these developments, the construction and observational strategies of BINGO have been defined. Conclusions. There is still no measurement of the BAO in radio, and studying cosmology in this new window of observations is one of the most promising advances in the field. The BINGO project is a radio telescope that has the goal to be one of the first to perform this measurement and it is currently being built in the northeast of Brazil. This paper is the first of a series of papers that describe in detail each part of the development of the BINGO project.

Context. Observing the neutral hydrogen (Hi ) distribution across the Universe via redshifted 21cm line intensity mapping (IM) constitutes a powerful probe for cosmology. However, the redshifted 21cm signal is obscured by the foreground emission from our Galaxy and other extragalactic foregrounds. This paper addresses the capabilities of the BINGO survey to separate such signals.Aims. We show that the BINGO instrumental, optical, and simulations setup is suitable for component separation, and that we have the appropriate tools to understand and control foreground residuals. Specifically, this paper looks in detail at the different residuals left over by foreground components, shows that a noise-corrected spectrum is unbiased, and shows that we understand the remaining systematic residuals by analyzing nonzero contributions to the three-point function. Methods. We use the generalized needlet internal linear combination (GNILC), which we apply to sky simulations of the BINGO experiment for each redshift bin of the survey. We use binned estimates of the bispectrum of the maps to assess foreground residuals left over after component separation in the final map. Results. We present our recovery of the redshifted 21cm signal from sky simulations of the BINGO experiment, including foreground components. We test the recovery of the 21cm signal through the angular power spectrum at different redshifts, as well as the recovery of its non-Gaussian distribution through a bispectrum analysis. We find that non-Gaussianities from the original foreground maps can be removed down to, at least, the noise limit of the BINGO survey with such techniques. Conclusions. Our component separation methodology allows us to subtract the foreground contamination in the BINGO channels down to levels below the cosmological signal and the noise, and to reconstruct the 21cm power spectrum for different redshift bins without significant loss at multipoles 20 500. Our bispectrum analysis yields strong tests of the level of the residual foreground contamination in the recovered 21cm signal, thereby allowing us to both optimize and validate our component separation analysis.

Context. BINGO (Baryon Acoustic Oscillations from Integrated Neutral Gas Observations.) is a radio telescope designed to survey from 980 MHz to 1260 MHz, observe the neutral hydrogen (Hi) 21 cm line, and detect the baryon acoustic oscillation signal with the intensity mapping technique. Here we present our method for generating mock maps of the 21 cm intensity mapping signal that cover the BINGO frequency range and related test results. Aims. We would like to employ N-body simulations to generate mock 21 cm intensity maps for BINGO and study the information contained in 21 cm intensity mapping observations about structure formation,Hi distribution and Hi mass-halo mass relation. Methods. We fit an Hi mass-halo mass relation from the ELUCID semianalytical galaxy catalog and applied it to the Horizen Run 4 halo catalog to generate the 21 cm mock map, which is called HOD. We also applied the abundance-matching method and matched the Horizen Run 4 galaxy catalog with the Hi mass function measured from ALFALFA, to generate the 21 cm mock map, which is called HAM Results. We studied the angular power spectrum of the mock maps and the corresponding pixel histogram. The comparison of two different mock map generation methods (HOD and HAM) is presented. We provide the fitting formula of Ω Hi , Hi bias, and the lognormal fitting parameter of the maps, which can be used to generate similar maps. We discuss the possibility of measuring Ω Hi and Hi bias by comparing the angular power spectrum of the mock maps and the theoretical calculation. We also discuss the redshift space distortion effect, the nonlinear effect, and the bin size effect in the mock map. Conclusions. By comparing the angular power spectrum measured from two different types of mock maps and the theoretical calculation, we find that the theoretical calculation can only fit the mock result at large scales. At small scales, neither the linear calculation nor the halofit nonlinear calculation can provide an accurate fitting, which reflects our poor understanding of the nonlinear distribution of Hi and its scale-dependent bias. We have found that the bias is highly sensitive to the method of populating Hi in halos, which also means that we can place constraints on the Hi distribution in halos by observing 21 cm intensity mapping. We also illustrate that only with thin frequency bins (such as 2 MHz), we can discriminate the Finger-of-God effect. All of our investigations using mocks provide useful guidance for our expectation of BINGO experiments and other 21 cm intensity mapping experiments.