Simbol-X Background Minimization: Mirror Spacecraft Passive Shielding Trade-Off Study

The present work shows a quantitative trade-off analysis of the Simbol-X Mirror Spacecraft (MSC) passive shielding, in the phase space of the various parameters: mass budget, dimension, geometry, and composition. A simplified physical (and geometrical) model of the sky screen, implemented by means of a GEANT4 simulation, has been developed to perform a performance-driven mass optimization and evaluate the residual background level on Simbol-X focal plane.Comment: 3 pages, 6 figures, to appear in the proceedings of the second Simbol-X International Symposium "Simbol-X - Focusing on the Hard X-ray Universe", AIP Conf. Proc. Series, P. Ferrando and J. Rodriguez ed

The AGILE gamma-ray satellite software system: real-time analysis and Apps for multi-wavelength and multi-messenger astronomy

I describe in this paper the AGILE real-time analysis (RTA), that is, the software system developed for the AGILE -ray Mission operations and scientific observations. Important tasks of the software include scientific alerts and follow-up observations in the multi-wavelength and multi-messenger context. Key elements of the AGILE RTA are a flexible software architecture, an efficient software management workflow, and an optimised team management implemented by the AGILE Team in more than 20 years of work. All these elements contributed to the success of the AGILE Mission, and they also constitute the basis for future projects of high-energy observatories. We also describe the smartphone APP AGILEScience that displays the scientific results of the Mission for professional and outreach purposes: it is an essential element of the AGILE Ground System and a unique “gate” to the -ray sky for the public audience

The AFISS web platform for the correlation of high-energy transient events

In the multi-messenger era, facilities share their results with the scientific community through networks such as the General Coordinates Network to study transient phenomena (e.g., Gamma-ray bursts) and implement real-time analysis pipelines to detect transient events, reacting to science alerts received from other observatories. The fast analysis of transient events is crucial for detecting counterparts of gravitational waves and neutrino candidate events. In this context, collecting scientific results from different high-energy satellites observing the same transient event represents a key step in improving the statistical significance of the high-energy candidate events. This project aims to develop a system and a web platform to share information and scientific results of transient events between high-energy satellites with INAF participation (AGILE, FERMI, INTEGRAL and SWIFT). The AFISS platform implements the COMET VO- Event broker and provides a web portal where the users visualize the list of transient events detected by multi-messenger facilities and received through the GCN. The web portal could show, for each event, a summary of the scientific results shared by the real-time analysis pipelines and a list of time-correlated transient events. In addition, the platform is ready to receive results from participating facilities on sub-threshold events (STE) that cannot be shared with the community due to the low statistical significance. If the platform finds a time correlation between two or more STEs, it can promote them to science alerts. The web interface shows the list of STEs with possible time correlation with other STEs or science alerts. The platform notifies the users with an email when a new transient event is received.Comment: 4 pages, 4 figures, Astronomical Data Analysis Software and System XXXII (31 October-4 November 2022

Evaluating the Maximum Likelihood Method for Detecting Short-Term Variability of AGILE gamma-ray Sources

The AGILE space mission (whose instrument is sensitive in the energy ranges 18-60 keV, and 30 MeV - 50 GeV) has been operating since 2007. Assessing the statistical significance of time variability of gamma-ray sources above 100 MeV is a primary task of the AGILE data analysis. In particular, it is important to check the instrument sensitivity in terms of Poisson modeling of the data background, and to determine the post-trial confidence of detections. The goals of this work are: (i) evaluating the distributions of the likelihood ratio test for "empty" fields, and for regions of the Galactic plane; (ii) calculating the probability of false detection over multiple time intervals. In this paper we describe in detail the techniques used to search for short-term variability in the AGILE gamma-ray source database. We describe the binned maximum likelihood method used for the analysis of AGILE data, and the numerical simulations that support the characterization of the statistical analysis. We apply our method to both Galactic and extra-galactic transients, and provide a few examples. After having checked the reliability of the statistical description tested with the real AGILE data, we obtain the distribution of p-values for blind and specific source searches. We apply our results to the determination of the post-trial statistical significance of detections of transient gamma-ray sources in terms of pre-trial values. The results of our analysis allow a precise determination of the post-trial significance of {\gamma}-ray sources detected by AGILE.Comment: 12 pages, 13 figures, 8 tables, accepted to A&