Transcript ska - Astrophysics

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 subarcsecond 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 ultrastrong-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.
Experimental Cosmology Group
Oxford Astrophysics