Today the scientific community is facing an increasing complexity of the scientific projects, from both a technological and a management point of view. The reason for this is in the advance of science itself, where new experiments with unprecedented levels of accuracy, precision and coverage (time and spatial) are realised. Astronomy is one of the fields of the physical sciences where a strong interaction between the scientists, the instrument and software developers is necessary to achieve the goals of any Big Science Project. The Cherenkov Telescope Array (CTA) will be the largest ground-based very high-energy gamma-ray observatory of the next decades. To achieve the full potential of the CTA Observatory, the system must be put into place to enable users to operate the telescopes productively. The software will cover all stages of the CTA system, from the preparation of the observing proposals to the final data reduction, and must also fit into the overall system. Scientists, engineers, operators and others will use the system to operate the Observatory, hence they should be involved in the design process from the beginning. We have organised a workgroup and a workflow for the definition of the CTA Top Level Use Cases in the context of the Requirement Management activities of the CTA Observatory. Scientists, instrument and software developers are collaborating and sharing information to provide a common and general understanding of the Observatory from a functional point of view. Scientists that will use the CTA Observatory will provide mainly Science Driven Use Cases, whereas software engineers will subsequently provide more detailed Use Cases, comments and feedbacks. The main purposes are to define observing modes and strategies, and to provide a framework for the flow down of the Use Cases and requirements to check missing requirements and the already developed Use-Case models at CTA sub-system level. Use Cases will also provide the basis for the definition of the Acceptance Test Plan for the validation of the overall CTA system. In this contribution we present the organisation and the workflow of the Top Level Use Cases workgroup.
The increasing number of Very High Energy (VHE) sources discovered by the current generation of Cherenkov telescopes made particularly relevant the creation of a dedicated source catalogs as well as the cross-correlation of VHE and lower energy bands data in a multi-wavelength framework. The “TeGeV Catalog” hosted at the ASI Science Data Center (ASDC) is a catalog of VHE sources detected by ground-based Cherenkov detectors. The TeGeVcat collects all the relevant information publicly available about the observed GeV/TeV sources. The catalog contains also information about public light curves while the available spectral data are included in the ASDC SED Builder tool directly accessible from the TeGeV catalogue web page. In this contribution we will report a comprehensive description of the catalog and the related tools.
The ASTRI project of the Italian National Institute for Astrophysics (INAF) is developing, in the framework of the Cherenkov Telescope Array (CTA), an end-to-end prototype system based on a dual-mirror small-sized Cherenkov telescope. Data preservation and accessibility are guaranteed by means of the ASTRI Archive System (AAS) that is responsible for both the on-site and off-site archiving of all data produced by the different sub- systems of the so-called ASTRI SST-2M prototype. Science, calibration, and Monte Carlo data together with the dedicated Instrument Response Functions (IRFs) (and corresponding metadata) will be properly stored and organized in different branches of the archive. A dedicated technical data archive (TECH archive) will store the engineering and auxiliary data and will be organized under a parallel database system. Through the use of a physical system archive and a few logical user archives that reflect the different archive use-cases, the AAS has been designed to be independent from any specific data model and storage technology. A dedicated framework to access, browse and download the telescope data has been identified within the proposal handling utility that stores and arranges the information of the observational proposals. The development of the whole archive system follows the requirements of the CTA data archive and is currently carried out by the INAF-OAR & ASI-Science Data Center (ASDC) team. The AAS is fully adaptable and ready for the ASTRI mini-array that, formed of at least nine ASTRI SST-2M telescopes, is proposed to be installed at the CTA southern site.
The Cherenkov Telescope Array (CTA) observatory will be one of the biggest ground-based very-high-energy (VHE) γ-
ray observatory. CTA will achieve a factor of 10 improvement in sensitivity from some tens of GeV to beyond 100 TeV
with respect to existing telescopes.
The CTA observatory will be capable of issuing alerts on variable and transient sources to maximize the scientific return.
To capture these phenomena during their evolution and for effective communication to the astrophysical community,
speed is crucial. This requires a system with a reliable automated trigger that can issue alerts immediately upon detection
of γ-ray flares. This will be accomplished by means of a Real-Time Analysis (RTA) pipeline, a key system of the CTA
observatory. The latency and sensitivity requirements of the alarm system impose a challenge because of the anticipated
large data rate, between 0.5 and 8 GB/s. As a consequence, substantial efforts toward the optimization of highthroughput
computing service are envisioned.
For these reasons our working group has started the development of a prototype of the Real-Time Analysis pipeline. The
main goals of this prototype are to test: (i) a set of frameworks and design patterns useful for the inter-process
communication between software processes running on memory; (ii) the sustainability of the foreseen CTA data rate in
terms of data throughput with different hardware (e.g. accelerators) and software configurations, (iii) the reuse of nonreal-
time algorithms or how much we need to simplify algorithms to be compliant with CTA requirements, (iv) interface
issues between the different CTA systems. In this work we focus on goals (i) and (ii).
ASTRI is the flagship project of INAF (Italian National Institute for Astrophysics) mainly devoted to the
development of Cherenkov small-size dual-mirror telescopes (SST-2M) in the framework of the international
Cherenkov Telescope Array (CTA) Project. ASTRI SST-2M is an end-to-end prototype including scientific and
technical operations as well as the related data analysis and archiving activities. We present here the ASTRI data
handling and archiving system: it is responsible for both the on-site and off-site data processing and archiving.
All the scientific, calibration, and engineering ASTRI data will be stored and organized in dedicated archives
aimed to provide access to both the monitoring and data analysis systems.