MeerKAT

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MeerKAT
MeerKAT prototype dish in 2014-1.jpg
MeerKAT prototype dish at HartRAO
Organization NRF
Department of Science and Technology[1]
SKA South Africa Project
Location Northern Cape, South Africa
Coordinates 30°43′16″S 21°24′40″E / 30.721°S 21.411°E / -30.721; 21.411Coordinates: 30°43′16″S 21°24′40″E / 30.721°S 21.411°E / -30.721; 21.411
Wavelength radio 3 centimetres (1.2 in) to 30 centimetres (12 in)
Built Under construction
Telescope style Radio interferometer
Collecting area ~18,000 square metres (190,000 sq ft) with 2,000 square metres (22,000 sq ft) built at July 2012
Website http://www.ska.ac.za/meerkat/index.php

MeerKAT is a radio telescope under construction in the Northern Cape of South Africa. It will be the largest and most sensitive radio telescope in the southern hemisphere until the Square Kilometer Array is completed around 2024.[1] The telescope will be used for research into cosmic magnetism, galactic evolution, the large-scale structure of the cosmos, dark matter and the nature of transient radio sources.[1] It will also serve as a technology demonstrator for South Africa's bid to host the Square Kilometer Array.[2] The KAT-7 engineering test bed of seven dishes is already complete on site. The construction and commissioning of the full MeerKAT array will follow.

Technical Specifications[edit]

MeerKAT will consist of 64 dishes of 13.5 metres in diameter each with an offset Gregorian configuration.[3] An offset dish configuration has been chosen because its unblocked aperture provides uncompromised optical performance and sensitivity, excellent imaging quality and good rejection of unwanted radio frequency interference from satellites and terrestrial transmitters. It also facilitates the installation of multiple receiver systems in the primary and secondary focal areas and is the reference design for the mid-band SKA concept.[4]

MeerKAT supports a wide range of observing modes, including deep continuum, polarisation and spectral line imaging, pulsar timing and transient searches. A range of standard data products are provided, including an imaging pipeline. A number of "data spigots" are also available to support user-provided instrumentation. Significant design and qualification efforts are planned to ensure high reliability to achieve low operational cost and high availability.

Technical Specifications
Number of antennas 64
Dish diameter 13.5 m
Minimum baseline 29 m
Maximum baseline 20 km
Frequency bands (receivers) 0.58 – 1.015 GHz
1 – 1.75 GHz
8 – 14.5 GHz
Continuum imaging dynamic range at 1.4 GHz 60 dB
Line-to-line dynamic range at 1.4 GHz 40 dB
Mosaicing imaging dynamic range at 1.4 GHz 27 dB
Linear polarisation cross coupling across −3 dB beam −30 dB

MeerKAT's 64 dishes will be distributed over two components:

  • A dense inner component containing 70% of the dishes. These are distributed in a two-dimensional fashion with a Gaussian uv-distribution with a dispersion of 300 m, a shortest baseline of 29 m and a longest baseline of 1 km.
  • An outer component containing 30% of the dishes. These are also distributed in a two-dimensional Gaussian uv-distribution with a dispersion of 2 500 m and a longest baseline of 8 km.

For Phase 2, seven additional antennas will be added to extend the longest baselines to about 20 km.

Construction Schedule[edit]

To build experience in the construction of interferometric telescopes, members of the Karoo Array Telescope constructed the Phased Experimental Demonstrator (PED) at the South African Astronomical Observatory in Cape Town between 2005 and 2007.[5]

During 2007, the 15 metres (49 ft) eXperimental Development Model Telescope (XDM) was built at the Hartebeesthoek Radio Astronomy Observatory to serve as a testbed for MeerKAT.[6]

Construction of the MeerKAT Precursor Array (MPA – also known as KAT-7), on the site started in August 2009.[7] The first seven dishes are complete. In April 2010 four of the seven dishes were linked together as an integrated system to produce its first interferometric image of an astronomical object. In Dec 2010, there was a successful detection of very long baseline interferometry (VLBI) fringes between the Hartebeesthoek Radio Astronomy Observatory 26 m dish and one of the KAT-7 dishes.[8]

Despite original plans to complete MeerKAT by 2012,[9] construction was suspended in late 2010 due to budget restructure. Science Minister Naledi Pandor denied the suspension marked any setback to the SKA project or 'external considerations'.[10] MeerKAT construction received no funding in 2010/11 and 2011/12.[11] The 2012 South African National Budget projected that just 15 MeerKAT antennas would be completed by 2015.[12]

The last of the reinforced concrete foundations for the MeerKAT antennas was completed on 11 February 2014. Almost 5000 m2 of concrete and over 570 tonnes of steel were used to build the 64 bases over a 9 month period.[13]

MeerKAT will be delivered in three phases. The commissioning of MeerKAT will take place in 2014 and 2015 with the array coming online for science operations in 2016. This phase will include all the antennas but only the first receiver will be fitted. A processing bandwidth of 750 MHz will be available. For the second and third phases the remaining two receivers will be fitted and the processing bandwidth will be increased to at least 2 GHz, with a goal of 4 GHz.

MeerKAT Phasing Schedule
2011
Precursor (KAT-7)
2016
MeerKAT Phase 1
2018
MeerKAT Phase 2 and 3
Number of dishes 7 64 64
Receiver bands (GHz) 0.9 – 1.6 1.00 – 1.75 0.58 – 1.015
1.00 – 1.75
8 – 14.5
Max processed BW (GHz) 0.256 0.75 2 (goal 4)
Max baseline (km) 0.2 8 20
Min baseline (m) 20 29 29

MeerKAT Science[edit]

Five years of observing time on MeerKAT have been allocated to leading astronomers who have applied for time to do research. The science objectives of the MeerKAT surveys are in line with the prime science drivers for the first phase of the SKA, confirming MeerKAT's designation as an SKA precursor instrument.

Science Projects Research Leaders
Testing Einstein's theory of gravity and gravitational radiation – Investigating the physics of enigmatic neutron stars through observations of pulsars. Prof Matthew Bailes, Swinburne Centre for Astrophysics and Supercomputing, Australia
LADUMA (Looking at the Distant Universe with the MeerKAT Array)[14] – An ultra-deep survey of neutral hydrogen gas in the early universe. Dr Sarah Blyth, University of Cape Town, South Africa
Dr Benne Holwerda, European Space Agency, The Netherlands
Dr Andrew Baker, Rutgers University, United States
MESMER (MeerKAT Search for Molecules in the Epoch of Reionization) – Searching for CO at high red-shift (z>7) to investigate the role of molecular hydrogen in the early universe. Dr Ian Heywood, University of Oxford, United Kingdom
MeerKAT Absorption Line Survey for atomic hydrogen and OH lines in absorption against distant continuum sources (OH line ratios may give clues about changes in the fundamental constants in the early universe). Dr Neeraj Gupta, ASTRON, The Netherlands
Dr Raghunathan Srianand, Inter-University Centre for Astronomy and Astrophysics, India
MHONGOOSE (MeerKAT HI Observations of Nearby Galactic Objects: Observing Southern Emitters) – Investigations of different types of galaxies, dark matter and the cosmic web. Prof Erwin de Blok, University of Cape Town, South Africa
TRAPUM (Transients and Pulsars with MeerKAT) – Searching for and investigating new and exotic pulsars. Dr Benjamin Stappers, Jodrell Bank Centre for Astrophysics, United Kingdom
Prof Michael Kramer, Max Planck Institute for Radio Astronomy, Germany
A MeerKAT HI Survey of the Fornax Cluster (Galaxy formation and evolution in the cluster environment). Dr Paolo Serra, ASTRON, The Netherlands
MeerGAL (MeerKAT High Frequency Galactic Plane Survey) – Galactic structure and dynamics, distribution of ionised gas, recombination lines, interstellar molecular gas and masers. Dr Mark Thompson, University of Hertfordshire, United Kingdom
Dr Sharmila Goedhart, SKA South Africa, South Africa
MIGHTEE (MeerKAT International GigaHertz Tiered Extragalactic Exploration survey) – Deep continuum observations of the earliest radio galaxies. Dr Kurt van der Heyden, University of Cape Town, South Africa
Dr Matt Jarvis, University of the Western Cape, South Africa and the University of Hertfordshire, United Kingdom
ThunderKAT (The Hunt for Dynamic and Explosive Radio Transients with MeerKAT) – e.g. gamma-ray bursts, novae and supernovae, plus new types of transient radio sources. Prof Patrick Woudt, University of Cape Town, South Africa
Prof Rob Fender, University of Southampton, United Kingdom

MeerKAT will also participate in global VLBI operations with all major radio astronomy observatories around the world and will add considerably to the sensitivity of the global VLBI network. Further potential science objectives for MeerKAT are to participate in the search for extraterrestrial intelligence and collaborate with NASA on downloading information from space probes.

See also[edit]

References[edit]

External video
Creamer Media's Shannon O'Donnell speaks to Engineering News senior contributing editor Keith Campbell about the MeerKAT radio telescope. 24 April 2009

External links[edit]