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Title: The agile alert system for gamma-ray transients

In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones andmore » tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.« less
Authors:
; ; ;  [1] ; ; ; ;  [2] ; ;  [3] ;  [4] ;  [5] ; ; ; ; ; ;  [6] ;  [7] ;  [8] more »; « less
  1. INAF/IASF-Bologna, Via Gobetti 101, I-40129 Bologna (Italy)
  2. INAF/IASF-Roma, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy)
  3. University of Modena and Reggio Emilia, Dipartimento di Science e Metodi dell'Ingegneria (Italy)
  4. INAF/IASF-Milano, Via E. Bassini 15, I-20133 Milano (Italy)
  5. School of Physics, University of the Witwatersrand, Johannesburg Wits 2050 (South Africa)
  6. INAF/IASF-Palermo, Via U. La Malfa 153, I-90146 Palermo (Italy)
  7. ASI-ASDC, Via G. Galilei, I-00044 Frascati (Roma) (Italy)
  8. INFN Trieste, I-34127 Trieste (Italy)
Publication Date:
OSTI Identifier:
22348179
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 781; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALGORITHMS; ASTROPHYSICS; COSMIC GAMMA SOURCES; DATA ANALYSIS; DETECTION; GAMMA RADIATION; GEV RANGE; MANAGEMENT; MEV RANGE; OPTIMIZATION; RESOURCES; SPACE; TELEPHONES; TRANSIENTS