Andrew Hopkins, Ron Ekers, Carole Jackson, Lawrence Cram, Anne Green, Dick Manchester, Lister Staveley-Smith and Ray Norris, PASA, 16 (2), in press.
Next Section: Primordial HI - Lister
Title/Abstract Page: Summary of the ``Sub-microJansky
Previous Section: Introduction
The Square Kilometre Array project
Under the auspices of the Large Telescope Working Group (LTWG), established in 1993 by the International Union of Radio Science (URSI), a large scientific community is now cooperating to discuss the technical research required for the realisation of the project. A group of 6 countries (Netherlands, U.S., China, Canada, Australia and India) are at present actively working on the technology study program. An internet site (http://www.atnf.csiro.au/1kT/) provides up-to-date information about the project (including the latest news, scientific and technical documents and the list of participant institutes).
At an earlier workshop (held in Sydney in December 1997), a list of preliminary specifications for the Square Kilometre Array was compiled (see http://www.atnf.csiro.au/1kT/, or http://www.nfra.nl/skai/science/index.htm). These specifications make it clear that the Square Kilometre Array will be the world's premier astronomical imaging instrument. It will have a spatial resolution better than the Hubble Space Telescope (<0.1 arcsec), a large field of view (
square degree), a spectral coverage of more than 50% (
), a spectral resolution sufficient for kinematic studies (
), and all at a sensitivity which is about 100 times that which is now available.
By comparison, the largest optical integral field units which are now being considered for construction on 8m telescopes would only provide a field of view of perhaps 1 arcmin on a side with 10% spectral coverage at a comparable resolution, while the next generation of millimetre arrays is envisaged to provide a field of about 40 arcsec with perhaps 10% spectral resolution.
There are still many possible hardware designs for the Square Kilometre Array, and a lot of effort is being devoted to ongoing studies to establish how each will address the desired specifications. The scientific justification for such an instrument is reaching maturity. The latest international meeting (held during July 1998 in Calgary) was devoted to producing the formal science case for the Square Kilometre Array. This will be used to refine the technical specification and design studies for the instrument.
In preparation for the Calgary meeting a workshop was held in June in Sydney, where Australian astronomers could speculate on the nature of the sub-microJansky radio sky and provide their own list of desired specifications for the Square Kilometre Array. This workshop investigated some specific areas of interest but did not cover all possible science goals which might be addressed with the Square Kilometre Array. However, with the advent of a new technology it is often not the questions expected to be answered which provide the most important discoveries, but those which no-one had thought to ask.
Perhaps the most exciting science driver for the Square Kilometre Array is the opportunity to study the origins of star- and galaxy-formation in the Universe, along with the large scale structure which is intimately connected with this process. This will be done through observations of redshifted HI and non-thermal emission from star forming regions in normal galaxies, like our own, at cosmological distances. However, the specifications for an instrument which can make such observations also allows the study of a wide range of other scientific targets. Amongst these are radio stars, pulsars, extended structures within the Milky Way, radio emission from normal galaxies, masers and spectral line studies, all of which were discussed in this workshop. There are many other astrophysical questions which the Square Kilometre Array will also address which were not discussed (e.g. galaxy evolution, large scale structure, gravitational lensing, Sunyaev-Zeldovich clusters, gamma ray bursters, extra-solar planets, solar-system objects, SETI applications, etc.) and the reader is directed to the most recent draft science case (LTWG 1998) for more information. Most of the material discussed during this workshop echoes aspects of material also developed by the LTWG, which will be available in full detail in the formal science case now being developed.
To provide a taste of the science which will be possible with the next generation radio telescope, and to list some of the instrumental specifications required along with some of the problems to be addressed, the topics discussed in the "Sub-microJansky Radio Sky" workshop are presented here.
Next Section: Primordial HI - Lister
Title/Abstract Page: Summary of the ``Sub-microJansky
Previous Section: Introduction
© Copyright Astronomical Society of Australia 1997