Brief history of Italy in the SKA project
Italy came into play in the SKA project on 10 August 2000. During a meeting of the International Astronomical Union in Manchester (UK), a group of countries interested in the project signed a memorandum of understanding to establish the International Steering Committee of the Square Kilometre Array (ISSC). Over a decade later, on 30 March 2011, a letter of intent was signed during a meeting in Rome, leading to the SKA Organisation's foundation later that year. On that occasion, Italy and INAF confirmed the prominent role they wanted the country to play in the SKA enterprise going forward. On 23 December 2014, the Italian Parliament approved the budget to fund Italy's economic involvement in the project.
From 2015 to 2018, Italy led the multilateral negotiations that set up the SKA Observatory as an intergovernmental organisation (IGO). On 24 May 2018, Italy was the first nation to initial the text of the Convention, ahead of the formal signature. A few months later, on 12 March 2019, in a ceremony in Rome, representatives of Australia, China, Italy, the Netherlands, Portugal, South Africa and the UK signed the international treaty establishing the SKAO.
Italian researchers and scientists, through the National Institute of Astrophysics (INAF), contribute to the discussions and refinement of all the SKA project’s scientific cases thanks to broad participation in the SKA Science Working Groups (SWGs). Overall, INAF and several Italian universities are involved in 13 of the 14 SKA Science Working Groups, and have been chairing several of them over time.
Furthermore, INAF researchers lead or are involved in numerous scientific studies related to SKA science published in major international journals and are already utilising the precursors and pathfinders of the SKA project. Over the years, while waiting for the actual operation of the SKA telescopes, INAF has joined the International LOFAR Telescope (ILT) in 2018 and the MeerKAT+ project (an extension of MeerKAT) in 2020. In addition to this, INAF is establishing a dedicated data analysis facility that will join the SKA Regional Centres (SRC) network, an alliance of data centres that will host cutting-edge IT infrastructures capable of processing and storing the amount of data produced by the SKA telescopes. The SRCs will also provide SKA users with proposal preparation and data management support.
The Italian research activities led, in 2014, to the publication of the Italian SKA White Book, which saw the involvement of more than 80 researchers. This effort has allowed the Italian scientific community to contribute to the SKA Science Book, published in 2015.
Building the SKAO’s telescopes
INAF has taken part in the technological development of the SKA since the beginning of the project through specific European programmes for research and technological development. During the design phase of the SKA telescopes, INAF has actively participated in four international consortia, whose general objective was to develop and finalise the design of all elements of the SKA. In particular, INAF was involved in:
- the design of the antennas, receivers and signal acquisition chain for the low-frequency antennas in Western Australia, in collaboration with the Universities of Bologna, Florence and Ferrara and the Cnr-Ieiit;
- the development of the monitoring and control software for the dishes in South Africa;
- the development of algorithms and data processing;
- the development of Phased Array Feed (PAF) receivers.
INAF has also created demonstrators of small aperture arrays, namely the Medicina Array Demonstrator (MAD) and the Sardinia Array Demonstrator (SAD), to gain experience and technologies useful for the development of the low-frequency array. Italian engineers then put this experience to use with the construction of demonstrators at CSIRO's Murchison Radio-astronomy Observatory (MRO), the future site of SKA-Low in Western Australia.. In addition, Italian experts led by INAF are involved in conducting tests to check the performance of two different antenna designs, including SKALA 4.1AL, which is the one chosen for the SKA-Low telescope.
Pathfinders & precursors: the Italian contribution
Italy makes a significant contribution to the SKAO and to the work of some precursors and pathfinders, in particular the MeerKAT extension (MeerKAT+) and LOFAR.
With MeerKAT+, the number of antennas of the world-class radio telescope MeerKAT will grow from 64 to 80, before being integrated into the SKA-Mid. The MeerKAT+ extension, initiated by SARAO and Max-Planck-Gesellschaft (MPG) and which INAF joined as a partner in 2020, will increase both the sensitivity and spatial resolution of the MeerKAT array of telescopes and thus provide a powerful tool for studying the formation and evolution of galaxies throughout the history of the universe. The telescope's computational requirements will also increase tenfold due to these improvements. The technological contributions of INAF researchers are of two types: the “local monitoring and control” software and the development of the correlator for the 80 antennas.
In addition, in 2018, Italy and INAF joined the International LOFAR Telescope. With over 25,000 antennas in 51 stations distributed in 7 European countries, LOFAR is the most extensive network for low-frequency radio astronomy observations. With the contract signing for constructing a new station in Medicina, near Bologna, LOFAR is becoming even more extensive which will increase further its observing capabilities. INAF leads a national consortium that includes the physics department of the University of Turin. Furthermore, INAF will develop a new generation of state-of-the-art electronic devices to equip this radio telescope spread throughout Europe.
Developing new technologies
Italian companies helped design the SKAO antennas and build the precursor telescopes, and they also engaged in spin-off applications of new technologies. In addition, many Italian industrial companies have collaborated by providing design and production support for the various working groups. For example, INAF, in collaboration with IEIIT and the Italian company Sirio Antenne, has developed SKALA 4.1AL, building on previous designs by an international consortium involving UK and Dutch colleagues. This is the design selected for the SKA-Low telescope antennas.
SKALA 4.1AL: antennas and receivers
The newest prototype design for SKA-Low, SKALA 4.1AL, has been developed by INAF in collaboration with IEIIT and Sirio Antenne, starting from the common electromagnetic design SKALA4, that was developed in partnership with the LFAA Consortium. SKALA 4.1AL is a dual-polarisation log-periodic antenna, resembling a Christmas tree, designed as a broad-band sensor. In collaboration with the Korean company Asb, the Italian team also developed a low-noise amplifier (LNA) installed on top of the antenna, which boosts the faint astronomical signal received. SKALA 4.1AL prototypes have been tested as part of a full station of 256 antennas, called Aperture Array Verification System 2.0 (AAVS2), whose installation was completed at the Murchison Radio Observatory by INAF engineers and technicians, with the support of Australian colleagues, in November 2019. Since 2004, INAF has also been working on the design of receivers for low-frequency systems (<2 GHz), introducing the so-called RFoF (Radio Frequency over Fibre) technology, which allows antenna arrays to carry all signals into a central facility.
The INAF team also led an international collaboration to design a digital/analogue system to acquire and process the received radio signals (Tile Processing Module, TPM). This task included developing a drone-based system (Unmanned Air Vehicle, UAV) to test the antennas. The UAV carries a transmitting antenna (e dipole) and a precise satellite positioning system; such devices make it possible to accurately test the behaviour of the SKA-Low prototype antennas from a distance of hundreds of metres. In addition, the Italian team visited the Murchison Radio-astronomy Observatory several times to conduct such measurement campaigns on the prototype antennas, in collaboration with the University of Malta and the Australian International Centre for Radio Astronomy Research (ICRAR).
The TPM digital platform is currently employed at the Northern Cross radio telescope, located at the INAF Medicina Radio Astronomical Station, for its participation in the European Space Surveillance and Tracking for surveying and tracking space debris and in the Fast Radio Burst research activities. Furthermore, researchers could also use the board prototype in various non-astronomical projects, like advanced radar, satellites and medical equipment like TAC or NMR.
The SKA project’s requirements challenge all current ICT technologies and methods of managing and analysing Big Data, which implies the design and implementation of an organisation that looks beyond the Exascale era and the development of skills at the front line of the research.
INAF is planning to engage in this challenge fully, building on the expertise developed so far also in the context of several European actions and infrastructures, such as AENEAS (Advanced European Network of E-infrastructures for Astronomy with the SKA), EUROHPC (European High-Performance Computing Joint Undertaking) and EOSC (European Open Science Cloud). In particular, INAF is establishing SRC-Italy, the Italian pole of the SKA Regional Centres (SRC), a network of data centres whose role is to host, analyse, exploit, cure and archive the data delivered by the SKA-Mid and the SKA-Low telescopes, also following the FAIR (Findable, Accessible, Interoperable, and Reusable) principles. It will be the primary entity in the context of the wider INAF Computing Facility. Moreover, it will promote the development of infrastructural synergies with the Bologna Technopole.
Given the size and peculiarity of the SKA project, it will also become a testbed for developing innovative software solutions useful for generic data management, analysis and visualisation. Furthermore, it will ensure expertise in critical sectors to foster Italy's growth in many digital assets, like data analytics and data mining.
The top-level observational requirements of the SKA project have also driven the realisation of a new commercial high-performing antenna working at 4G-LTE frequencies (698-2700 MHz)* developed by the Italian industrial company Sirio Antenne, contractor of INAF in the SKA project, taking inspiration from the SKALA 4.1-AL antenna created for the SKA-Low telescope. The antenna obtained excellent feedback from the European market and won a tender in France for the electrical network supplier (for ENEDIS / EDF FRANCE, for remote power consumption reading).
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