Detection of short Gamma-Ray Bursts with CTA through real-time analysis

With respect to the current IACTs, CTA will cover a larger energy range (~20 GeV - 300 TeV) with one order of magnitude better sensitivity. The facility will be provided with a real-time analysis (RTA) software that will automatically generate science alerts and analyse data from on-going observations in real-time. The RTA will play a key role in the search and follow-up of transients from external alerts (i.e. from on-space gamma-ray missions, observatories operating at other energy bands or targets of opportunity provided by neutrinos and gravitational waves detectors). The scope of this study was to investigate the ctools software package feasibility for the RTA, adopting a full-field of view maximum likelihood analysis method. A prototype for the RTA was developed, with natively implemented utilities where required. Its performance was extensively tested for very-short exposure times (far below the lower limit of current Cherenkov science) accounting for sensitivity degradation due to the non-optimal working condition expected of the RTA. The latest IRFs, provided by CTA Performance, were degraded via effective area reduction for this purpose. The reliability of the analysis methods was tested by means of the verification of Wilks' theorem. Through statistical studies on the pipeline parameter space (i.e. minimum required exposure time), the performance was evaluated in terms of localization precision, detection significance and detection rates at short-timescales using the latest available GRB afterglow templates for the source simulation. Future improvements involve further tests (i.e. with an updated population synthesis) as well as post-trials correction of the detection significance. Moreover, implementations allowing the pipeline to dynamically adapt to a range of science cases are required. Prospects of forthcoming collaboration may involve the integration of this pipeline within the on-going work of the gamma-ray bursts experts of CTA Consortium

Agilepy: A Python framework for AGILE data

The Italian AGILE space mission, with its Gamma-Ray Imaging Detector (GRID) instrument sensitive in the 30 Me–50 GeV γray energy band, has been operating since 2007. Agilepy is an open-source Python package to analyse AGILE/GRID data. The package is built on top of the command-line version of the AGILE Science Tools, developed by the AGILE Team, publicly available and released by ASI/SSDC. The primary purpose of the package is to provide an easy to use high-level interface to analyse AGILE/GRID data by simplifying the configuration of the tasks and ensuring straightforward access to the data. The current features are the generation and display of sky maps and light curves, the access to \gray sources catalogues, the analysis to perform spectral model and position fitting, the wavelet analysis. Agilepy also includes an interface tool providing the time evolution of the AGILE off-axis viewing angle for a chosen sky region. The Flare Advocate team also uses the tool to analyse the data during the daily monitoring of the γray sky. Agilepy (and its dependencies) can be easily installed using Anaconda

Detection methods for the Cherenkov Telescope Array at very-short exposure times

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy, with the deployment of tens of highly sensitive and fast-reacting Cherenkov telescopes. It will cover a wide energy range (20 GeV - 300 TeV) with unprecedented sensitivity. To maximize the scientific return, the observatory will be provided with an online software system that will perform the first analysis of scientific data in real-time. This study investigates the precision and accuracy of available science tools and analysis techniques for the short-term detection of gamma-ray sources, in terms of sky localization, detection significance and, if significant detection is achieved, a first estimation of the integral photon flux. The scope is to evaluate the feasibility of the algorithms' implementation in the real-time analysis of CTA. In this contribution we present a general overview of the methods and some of the results for the test case of the short-term detection of a gamma-ray burst afterglow, as the VHE counterpart of a gravitational wave event.Comment: Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), PoS(ICRC2021)69, 8 pages + full author list, 5 figure

Detection methods for the Cherenkov Telescope Array at very-short exposure times

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy, with the deployment of tens of highly sensitive and fast-reacting Cherenkov telescopes. It will cover a wide energy range (20 GeV - 300 TeV) with unprecedented sensitivity. To maximize the scientific return, the observatory will be provided with an online software system that will perform the first analysis of scientific data in real-time. This study investigates the precision and accuracy of available science tools and analysis techniques for the short-term detection of gamma-ray sources, in terms of sky localization, detection significance and, if significant detection is achieved, a first estimation of the integral photon flux. The scope is to evaluate the feasibility of the algorithms' implementation in the real-time analysis of CTA. In this contribution we present a general overview of the methods and some of the results for the test case of the short term detection of a gamma-ray burst afterglow, as the VHE counterpart of a gravitational wave event

Ottica geometrica e ondulatoria, e applicazioni astrofisiche

Lo studio dell'ottica si incentra sull'indagine della natura della luce, delle sue proprietà e delle leggi che ne regolano i fenomeni fisici. Si possono, in complessivo, identificare tre branche: l'ottica geometrica, l'ottica ondulatoria e l'ottica quantistica. Quest'ultima esula dalla presente trattazione, che piuttosto si incentra sull'aspetto geometrico ed ondulatorio della radiazione luminosa. Con l'ottica geometrica viene identificato lo studio della luce come propagazione rettilinea di raggi luminosi. Essa include lo studio degli specchi e delle lenti, di particolare interesse per le applicazioni nella strumentazione astrofisica. All'interno del primo capitolo, dunque, sono enunciate le principali leggi che definiscono la propagazione rettilinea della luce, la sua riflessione contro una superficie o la sua rifrazione attraverso due mezzi differenti. L'ottica geometrica, in effettivo, consiste in un caso limite della più generica trattazione fornita dall'ottica ondulatoria. La condizione che demarca la possibilità di approssimare la trattazione nell'ambito geometrico, è definita dalla richiesta che la lunghezza d'onda della radiazione in esame sia di molto inferiore delle dimensioni lineari dell'ostacolo con cui interagisce. Qualora tale condizione non fosse soddisfatta, la considerazione della natura ondulatoria della luce non sarebbe più trascurabile. Nel secondo capitolo dell'elaborato, dunque, vengono presi in esame il modello ondulatorio della radiazione elettromagnetica ed alcuni fenomeni fisici che ne avvalorano la fondatezza; in particolare i fenomeni dell'interferenza e della diffrazione. Infine, nel terzo ed ultimo capitolo, sono affrontati alcuni esempi di applicazioni astrofisiche, sia nell'ambito dell'ottica geometrica che nell'ambito dell'ottica ondulatoria

Detection methods for the Cherenkov Telescope Array at very-short exposure times

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy, with the deployment of tens of highly sensitive and fast-reacting Cherenkov telescopes. It will cover a wide energy range (20 GeV - 300 TeV) with unprecedented sensitivity. To maximize the scientific return, the observatory will be provided with an online software system that will perform the first analysis of scientific data in real-time. This study investigates the precision and accuracy of available science tools and analysis techniques for the short-term detection of gamma-ray sources, in terms of sky localization, detection significance and, if significant detection is achieved, a first estimation of the integral photon flux. The scope is to evaluate the feasibility of the algorithms’ implementation in the real-time analysis of CTA. In this contribution we present a general overview of the methods and some of the results for the test case of the short-term detection of a gamma-ray burst afterglow, as the VHE counterpart of a gravitational wave event

Agilepy: A Python Framework for AGILE Data Analysis

The Italian AGILE space mission, with its Gamma-Ray Imaging Detector (GRID) instrument sensitive in the 30 Me–50 GeV γray energy band, has been operating since 2007. Agilepy is an open-source Python package to analyse AGILE/GRID data. The package is built on top of the command-line version of the AGILE Science Tools, developed by the AGILE Team, publicly available and released by ASI/SSDC. The primary purpose of the package is to provide an easy to use high-level interface to analyse AGILE/GRID data by simplifying the configuration of the tasks and ensuring straightforward access to the data. The current features are the generation and display of sky maps and light curves, the access to \gray sources catalogues, the analysis to perform spectral model and position fitting, the wavelet analysis. Agilepy also includes an interface tool providing the time evolution of the AGILE off-axis viewing angle for a chosen sky region. The Flare Advocate team also uses the tool to analyse the data during the daily monitoring of the γray sky. Agilepy (and its dependencies) can be easily installed using Anaconda...

Requirement Verification for Science Alert Generation Pipeline of the ACADA subystem

This specification describes a plan to conduct requirements verification to assess for the de- sired performance, design, development, test and qualification requirements defined for the Science Alert Generation Pipeline (SAG) sub-system of the Array Control and Data Acqui- sition (ACADA) System of CTAO