From the category archives:

2010astro

Understanding our gas-guzzling home: the Milky Way

“There’s a lot we still don’t know about our Milky Way galaxy,” says Dr Naomi McClure-Griffiths of the Australia Telescope National Facility. “It’s the old forest and the trees problem – we have a hard time seeing its structure from the inside.”
Since 2004, Naomi has headed the Galactic All Sky Survey, or GASS, the most [...]

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How to cope with being inundata’d

The world’s largest telescope, the Square Kilometre Array (SKA), is expected to generate more data in a single day, than the world does in a year at present. And even its prototype, the Australia SKA Pathfinder (ASKAP), is expected to accumulate more information within six hours of being switched on than has been stored by all previous radio telescopes combined.

Such gargantuan streams of data require serious management, and that will be the job of the $80 million Pawsey High-Performance Computing Centre for SKA Science in Perth. Contracts for the construction of the building to house the Centre are expected to be let in December, 2010.

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No moving parts – a new kind of radio telescope

Far outback in Western Australia, at the Murchison Radio Astronomy Observatory located on Boolardy Station, 315 km north-east of Geraldton, 32 tiles each carrying 16 dipole antennas have begun to collect scientific data on the Sun. At the same time they are providing engineering information to be used to extend the facility to a much bigger array of 512 tiles-the Murchison Widefield Array (MWA).

The MWA is designed to study radio sources at low frequencies, a poorly known part of the radio spectrum between 80 and 300 megahertz. It will be one of the world’s first telescopes without any moving parts. In fact, the array is ’steered’ electronically, which means the direction the telescope points depends entirely on how the signals from its stationary antennas are combined and processed.

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Australia’s biggest digital camera – 268 mega pixels

On a mountaintop in northern NSW sits a new telescope equipped with Australia’s largest digital camera. The ANU’s SkyMapper facility has been established at Siding Spring Observatory to conduct the most comprehensive optical survey yet of the southern sky.

Fully automated, the telescope is measuring the shape, brightness and spectral type of over a billion stars and galaxies, down to one million times fainter than the eye can see.

The heart of the system is a $2.5 million, 268- mega pixel digital camera that covers an area 40 times greater than the full Moon every minute. The huge data set (100 megabytes per second) will be shared with the astronomical community and wider public.

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The hunt for invisible ripples in space and time

Einstein’s theories predicted them, and they could be everywhere throughout the universe. But they’ve never been directly detected. They are gravitational waves, unseen “ripples” in the fabric of space and time.

Scientists using CSIRO’s Parkes radio telescope are leading the way in trying to find them, by studying signals coming from pulsars.

Pulsars are the collapsed cores of giant stars that have exploded. Spinning at up to hundreds of times per second, they emit highly-regular radio pulses that appear to flash on and off like a lighthouse. And that’s the key.

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The sky’s no limit with ASKAP

The world’s most advanced “sky survey” radio telescope is taking shape in a remote part of Western Australia inland from Geraldton.

The 36-dish Australian Square Kilometre Array Pathfinder, or ASKAP, features new CSIRO-developed “focal plane array” technology that gives it a huge 30º field of view. “So instead of concentrating on one small patch, we can cover the whole sky in a fairly short space of time,” says Dr Simon Johnston, ASKAP project scientist.

A large dynamic range-the difference between the strongest and weakest signals picked up- is another advantage. “We’re aiming to get a dynamic range 10 to 100 times better than CSIRO’s current flagship telescope, the Compact Array,” says Simon.

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Galaxy “super survey” will be 10 ten times better

A new “super survey” is producing the largest database of galaxy measurements, spanning the last five billion years of cosmic history.

The international GAMA (Galaxy and Mass Assembly) project is combining data from ground- and space-based observatories to measure the dark matter “haloes” that surround galaxies. Dark matter, its nature still unknown, makes up 24% per cent of the universe.

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PC technology drives a new revolution in astronomy

The technology used in your PC or PlayStation is also helping drive a revolution in radio astronomy-the replacement of custom-built hardware with flexible software and data solutions.

“Hardware solutions for radio astronomy have been evolving, but computer power has been evolving much faster,” says Prof. Matthew Bailes, Director of the Swinburne Centre for Astrophysics and Supercomputing. The Centre has developed software systems that are now used in Australia and overseas.

The rapid advance of computer processing power and network speeds have been a boon for the High Time Resolution Universe Survey, headed by Matthew, which uses the Parkes telescope to scan the sky for fast-occurring short duration radio signals.

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Will WiggleZ unmask the universe’s dark secret?

A project to produce more than double the number of galaxy distance measurements than all other previous surveys combined, could lead to an explanation of one of nature’s biggest mysteries.

In 1998, astronomers announced that the expansion of the universe is not slowing down as many people had thought, but rather is speeding up. To account for this, scientists have invoked an invisible force called “dark energy”, which makes up 75% of the cosmos’ total of energy and matter in the cosmos. Dark energy opposes gravity, and makes the universe want to spread out.

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Mapping magnetism to reveal cosmic history

The largest-ever survey of magnetic fields in the universe will boost our knowledge of cosmic history.

“Magnetic fields are important because they basically tell gas in the universe how to move,” says Prof. Bryan Gaensler, an astrophysicist at The University of Sydney. “And because gas is the ingredient that makes galaxies, stars and planets, it’s vital we know magnetism’s influence if we’re to understand how the universe has evolved.”

Magnetic fields in distant space can’t be measured directly. Astronomers have to rely on the effect magnetism has on the polarisation of electromagnetic waves such as radio waves, and light waves) reaching their telescopes.

Bryan heads a team that will use the ASKAP radio telescope, under construction in Western Australia, to conduct POSSUM-the POlarisation Sky Survey of the Universe’s Magnetism. ASKAP will be the ideal facility when it comes online in 2013, as it has “fish-eye lens” technology that will enable it to cover huge areas of the sky in one go.

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