Thu, 22. November 2012
Astro-Speaker Watch - November 2012
Emil works with MAS Patron, Professor Bryan Gaensler, at the Sydney Institute for Astronomy at Sydney University. He is a latecomer to astro-physics, working in the private sector as a software engineer for ten years, before studying astronomy at Swinburne University. He took us through a brief history of radio astronomy from Karl Guthe Jansky around 1933 to the current revolution which will culminate at the end of the decade with the commissioning of Stage 1 of the SKA telescope.
The SKA will be split between South Africa and the Australian site at remote Murchison, Western Australia, where already two SKA precursor telescopes have been built and are undergoing commissioning. These are the Murchison Widefield Array (MWA) and the Australian Square Kilometre Array Precursor (ASKAP). They both share a 10 GB/sec optical fibre link all the way to the Pawsey Computer Centre in Perth.
Emil went on to describe the Murchison Widefield Array and talked about it's potential. These images by Emil show the MWA and its surrounds and are best viewed full screen:
The MWA is a low-frequency radio telescope, receiving UHF signals at 80-300 MHz. Its scientific goals are "to detect neutral atomic Hydrogen emission from the cosmological Epoch of Reionization(EoR), to study the Sun, the heliosphere, the Earth's ionosphere, and to study radio transient phenomena". It will be fully operational in 2013. The larger the number of antennas the greater the sensitivity and the better the fidelity of the final image. The larger the area covered (the longer the baselines), the higher the resolution of the instrument.
The MWA has 128 tiles, with 112 inside a 1.5 km core, "providing very high imaging quality, and a field of view of several hundred square degrees at a resolution of several arcminutes". The other 16 tiles outside the core will provide a baseline distance of about 3 km. The hope is that sensitivity can be increased by doubling the number of tiles to 256. Each tile consists of sixteen crossed dipole antannae. The telescope is a low budget instrument and the antennae tilles were all assembled and pre-wired by a gang of students, led by Kirsten Gottschalke from the International Centre for Radio Astronomy Research.
Emil is one of the team of commissioning scientists for the MWA and he has already started to get some amazing images. The following video clip shows a time lapse of the sky scrolling overhead, with the telescope not following the drift. Have a cursory look and you would think "ho-hum , nice stars" but these are not stars; they are not even just galaxies; they are all black holes! View full screen:
Below is Emil's first commissioning image (taken 28th Ocober 2012), made "with less than a minutes worth of data collected from the shiny new MWA "gamma" array. The spot in the middle is Virgo A (or M87 for those that are familiar with its optical counterpart). The remaining points are other radio sources in the field - a field that is approximately 400 sq. degrees in size!"
This MWA instrument is unique in providing high resolution wide fields of view at low radio wavelengths in the southern hemisphere; and Emil Lenc has certainly stoked up a lot of interest in it at MAS with his interesting talk.
AT THE MACARTUR ASTRONOMY FORUM:
December 2012: No meeting
January 2013: Astronomy apps on mobile devices - Chris Malikoff
EDITED 23rd November. Clarified that the talk began with radio astronomy in the 1930s and improved the paragraph on resolution and fidelity. (Thanks Emil. I'll pay more attention next time!)
Astro-Speaker Watch is a series of articles recording the talks given at Macarthur Astronomy Forum, held by Macarthur Astronomical Society at the University of Western Sydney, Campbelltown. The first article in the series was written in March 2012.