Kilometre Array Project Research Articles

Radio Astronomical Antennas in the Central African Region to Improve the Sampling Function of the VLBI Network in the SKA Era?

On the African continent, South Africa has world-class astronomical facilities for advanced radio astronomy research. With the advent of the Square Kilometre Array project in South Africa (SA SKA), six countries in Africa (SA SKA partner countries) have joined South Africa to contribute towards the African Very Long Baseline Interferometry (VLBI) Network (AVN). Each of the AVN countries aims to construct a single-dish radio telescope that will be part of the AVN, the European VLBI Network, and the global VLBI network. The SKA and the AVN will enable very high sensitivity VLBI in the southern hemisphere. In the current AVN, there is a gap in the coverage in the central African region. This work analyses the increased scientific impact of having additional antennas in each of the six countries in central Africa, i.e., Cameroon, Gabon, Congo, Equatorial Guinea, Chad, and the Central African Republic. A number of economic human capital impacts of having a radio interferometer in central Africa are also discussed. This work also discusses the recent progress on the AVN project and shares a few lessons from some past successes in ground stations retrofitting.

Future radio continuum cosmology clustering surveys

ABSTRACT The use of continuum emission radio galaxies as cosmological tracers of the large-scale structure will soon move into a new phase. Upcoming surveys from the Australian Square Kilometre Array Pathfinder (ASKAP), MeerKAT, and the Square Kilometre Array project (SKA) will survey the entire available sky down to an $\sim 100\, \mu$Jy flux limit, increasing the number of detected extra-galactic radio sources by several orders of magnitude. External data and machine learning algorithms will also enable some low-resolution radial selection (photometric redshift binning) of the sample, increasing the cosmological utility of the sample observed. In this paper, we discuss the flux limit required to detect enough galaxies to decrease the shot-noise term in the error to be 10 per cent of the total. We show how future surveys of this type will be limited by available technology. The confusion generated by the intrinsic sizes of galaxies may have the consequence that surveys of this type eventually reach a hard flux limit of ∼100 nJy, as is predicted by the current modelling of AGN sizes by simulations such as the Tiered Radio Extragalactic Continuum Simulation (T-RECS). Finally, when considering the multitracer approach, where galaxies are split by type to measure some bias ratio, we find that there are not enough AGN present to achieve a reasonable level of shot noise for this kind of measurement.

A sustainable software testing process for the Square Kilometre Array project

AbstractIn this paper we show how to achieve a sustainable software testing process in a very complex scientific project, the Square Kilometre Array (SKA) radio observatory. The project currently involves 13 countries, 16 agile development teams of about 150 individuals, governed through the Scalable Agile Framework (SAFe) framework; the software that is being built ranges from user interfaces to control systems, from transactional applications to high performance parallel scientific processing code.The paper illustrates the testing challenges we have to tackle; it also defines what a “sustainable testing process” is and how that constitutes the foundation of an incremental adoption plan rooted on systems thinking. The plan is then described, highlighting the principles we adhered to for synthesising a sequence of 9 basic testing goals that are currently being rolled out.We are confident that similar decisions can be made on many large scientific projects that are developed with agile methods.

Science Diplomacy in the Indo‐Pacific Region: A Mixed but Promising Experience

Among other things, a globalizing world has challenged the old dichotomy between science and diplomacy and helped to facilitate the advent of Science Diplomacy. This term encompasses a particular form of public diplomacy and refers to the use of scientific collaborations among nations to tackle common challenges. Science Diplomacy operates on the assumption that many of today's problems—food, water, energy, climate, and health—cannot be solved by any single state and, more often than not, require international technical or scientific solutions. Does Science Diplomacy represent a major paradigm change or simply a minor adjustment in the making of foreign policy? In the Indo‐Pacific, the need for Science Diplomacy is clear, but at present there are mixed signals on whether states in the region are really prepared to develop its potential. On one hand, the Square Kilometre Array project—the construction of a large radio telescope in Australia and South Africa from 2018—represents a good example of a multilateral diplomatic effort to facilitate and extend scientific collaboration to dramatically improve human capabilities to survey the sky. On the other, science diplomacy has so far largely failed to live up to its potential to address climate change, the most significant threat to the future of the Indo‐Pacific region and the world beyond. However, successful efforts to make Ross Sea a global marine sanctuary also shows that, despite obstacles, Science Diplomacy can sometime have spillover effects into political decision making with positive outcomes. This mixed picture highlights a paradox. While the emergence of Science Diplomacy reflects a recognition by states that a growing number of national problems require international scientific solutions, such recognition remains patchy and somewhat uneven. Many states, particularly the most powerful ones, continue to be constrained in the international arena by the old Westphalian idea of unfettered state sovereignty.

Mathematical and statistical foundations and challenges of (big) data sciences

The hype around data sciences in general and big data in particular and the focus either on the potential commercial value of data analytics or on promoting its adoption as a new paradigm in conducting research, may crowd out important discussions that need to take place about the theoretical foundations of this ‘emerging’ discipline. In South Africa, discussions around (or the mere mention of) big data, especially within the National System of Innovation, often go hand in glove either with the Square Kilometre Array project and astrophysics, or eResearch or cyberinfrastructure.

EMBRACE@Nançay: an ultra wide field of view prototype for the SKA

A revolution in radio receiving technology is underway with the development of densely packed phased arrays for radio astronomy. This technology can provide an exceptionally large field of view, while at the same time sampling the sky with high angular resolution. Such an instrument, with a field of view of over 100 square degrees, is ideal for performing fast, all-sky, surveys, such as the ``intensity mapping'' experiment to measure the signature of Baryonic Acoustic Oscillations in the HI mass distribution at cosmological redshifts. The SKA, built with this technology, will be able to do a billion galaxy survey. I will present a very brief introduction to radio interferometry, as well as an overview of the Square Kilometre Array project. This will be followed by a description of the EMBRACE prototype and a discussion of results and future plans.

Germany withdraws from Square Kilometre Array project

Germany withdraws from Square Kilometre Array project

Resisting the Restoration: response to Premesh Lalu

Resisting the Restoration: response to Premesh Lalu