No Arabic abstract
This document describes the top level requirements for the SKA-AAMID telescope as determined by the SKA key science projects. These include parameters such as operating frequency range,instantaneous bandwidth (total processed bandwidth), field of view (or survey speed, as appropriate), sensitivity, dynamic range, polarization purity etc. Moreover, through the definition of a set of science requirements, this document serves as input to a number of other documents contained within the System Requirements Review package. (particularly SKA-TEL-MFAA-0200005: `SKA-AAMID System Requirements and SKA-TEL-MFAA-0200008: `MFAA Requirements).
The Square Kilometre Array (SKA) is the next generation radio telescope. Aperture Arrays (AA) are considered for SKA-2 for frequencies up to 1.4 GHz (SKA-1 uses AAs up to 350 MHz). This document presents design considerations of this Mid-Frequency Aperture Array (MFAA) element and possible system architectures complying with the SKA-2 system requirements, combining high sensitivity with a superb survey speed. The architectural analyses has been submitted to the System Requirements Review of the MFAA element.
The Murchison Widefield Array is a low frequency (80 - 300 MHz) SKA Precursor, comprising 128 aperture array elements (known as tiles) distributed over an area of 3 km diameter. The MWA is located at the extraordinarily radio quiet Murchison Radioastronomy Observatory in the mid-west of Western Australia, the selected home for the Phase 1 and Phase 2 SKA low frequency arrays. The MWA science goals include: 1) detection of fluctuations in the brightness temperature of the diffuse redshifted 21 cm line of neutral hydrogen from the epoch of reionisation; 2) studies of Galactic and extragalactic processes based on deep, confusion-limited surveys of the full sky visible to the array; 3) time domain astrophysics through exploration of the variable radio sky; and 4) solar imaging and characterisation of the heliosphere and ionosphere via propagation effects on background radio source emission. This paper concentrates on the capabilities of the MWA for solar science and summarises some of the solar science results to date, in advance of the initial operation of the final instrument in 2013.
The Square Kilometre Array will revolutionize pulsar studies with its wide field-of-view, wide-band observation and high sensitivity, increasing the number of observable pulsars by more than an order of magnitude. Pulsars are of interest not only for the study of neutron stars themselves but for their usage as tools for probing fundamental physics such as general relativity, gravitational waves and nuclear interaction. In this article, we summarize the activity and interests of SKA-Japan Pulsar Science Working Group, focusing on an investigation of modified gravity theory with the supermassive black hole in the Galactic Centre, gravitational-wave detection from cosmic strings and binary supermassive black holes, a study of the physical state of plasma close to pulsars using giant radio pulses and determination of magnetic field structure of Galaxy with pulsar pairs.
The signal processing firmware that has been developed for the Low Frequency Aperture Array component of the Square Kilometre Array is described. The firmware is implemented on a dual FPGA board, that is capable of processing the streams from 16 dual polarization antennas. Data processing includes channelization of the sampled data for each antenna, correction for instrumental response and for geometric delays and formation of one or more beams by combining the aligned streams. The channelizer uses an oversampling polyphase filterbank architecture, allowing a frequency continuous processing of the input signal without discontinuities between spectral channels. Each board processes the streams from 16 antennas, as part of larger beamforming system, linked by standard Ethernet interconnections. There are envisaged to be 8192 of these signal processing platforms in the first phase of the Square Kilometre array so particular attention has been devoted to ensure the design is low cost and low power.
The Murchison Widefield Array is a low frequency (80 - 300 MHz) SKA Precursor, comprising 128 aperture array elements distributed over an area of 3 km diameter. The MWA is located at the extraordinarily radio quiet Murchison Radioastronomy Observatory in the mid-west of Western Australia, the selected home for the Phase 1 and Phase 2 SKA low frequency arrays. The MWA science goals include: 1) detection of fluctuations in the brightness temperature of the diffuse redshifted 21 cm line of neutral hydrogen from the epoch of reionisation; 2) studies of Galactic and extragalactic processes based on deep, confusion-limited surveys of the full sky visible to the array; 3) time domain astrophysics through exploration of the variable radio sky; and 4) solar imaging and characterisation of the heliosphere and ionosphere via propagation effects on background radio source emission. This paper will focus on a brief discussion of the as-built MWA system, highlighting several novel characteristics of the instrument, and a brief progress report (as of June 2012) on the final construction phase. Practical completion of the MWA is expected in November 2012, with commissioning commencing from approximately August 2012 and operations commencing near mid 2013. A brief description of recent science results from the MWA prototype instrument is given.