Square Kilometre Array (SKA)

1. Square Kilometre Array (SKA) Overview The SKA is the next step forward in high precision radio astronomy, with the start of construction set for 2012­2015. It will have the equivalent resolving power of a dish with an area of ~106 m2. With a frequency range of 0.15–22 GHz, there are a large range of applications of such an instrument. A sub-arcsecond resolution combined with a 10–100 deg2 field of view lend the SKA both to high precision astrometry and large surveys. SKA is an international project between eleven countries (Australia, Canada, China, Germany, India, Italy, the Netherlands, Poland, Sweden, the UK and the USA), with possible locations being South Africa, Argentina, Australia and China. The improved sensitivity is shown on the left, with conceptual designs for the array itself on the far left. The Cradle of Life The SKA will be able to provide thermal imaging at 20 GHz at 0.15 AU resolution out to a distance of 150 pc, allowing the study of terrestrial planet formation in many nearby star-forming regions (left). The evolution of such systems will be observable over timescales of months, giving the first “movies” of planet formation. Up to a million solar-type stars could be searched for signals from extraterrestrial intelligences. Transitions of amino acids could be detected and tracked from molecular clouds to protoplanets. Test of Gravity Surveys has the ability to survey tens of thousands of pulsars with a very high chance of finding one orbiting a black hole (right). This would give us the first test of gravity in the ultra-strong-field limit. Millisecond pulsar timings could also be used to look for cosmological gravitational waves, with each pulsar acting as one very long arm of an interferometer (far right). Magnetism SKA will be able to probe the galactic and intergalactic magnetic field (left) down to scales of 60’’ by looking at Faraday rotation, polarised synchrotron emission (far left) and the Zeeman effect. The origin of the first magnetic fields and their evolution from z > 3 could also be investigated. Galaxy Evolution and Cosmology The SKA will be able to detect HI emission in normal galaxies at high redshift, allowing a study of the evolution of neutral Hydrogen (right). Weak gravitational lensing will allow the measurement of the dark matter power spectrum, while extragalactic masers will allow the precise determination of H0. Combined with Planck and other CMB data, SKA will remove the degeneracies in all the Cosmological Parameters and reduce the errors by several orders of magnitude. The Early Universe Studies of the HI 21cm emission line (left) will allow SKA to probe the Epoch of Reionisation, which will improve our understanding of the evolution of large scale structures. SKA will also be sensitive enough to study gas, dust and star formation in the first galaxies for the first time.