Galactic shutterbug

A new instrument at the Australian Astronomical Observatory (AAO) can sample the light coming from hundreds of galaxies per night—which can tell us new things about the universe.

Astronomer Sam Richards sitting in the prime focus cage at the Anglo-Australian Telescope, where the SAMI instrument usually sits. Credit: Jon Lawrence
Astronomer Sam Richards sitting in the prime focus cage at the Anglo-Australian Telescope, where the SAMI instrument usually sits. Credit: Jon Lawrence

Sydney-AAO Multi-object Integral field spectrograph (SAMI) can look at up to 100 galaxies in a night, because it can look at 60 different regions in each of 13 different galaxies, all at once.

But most observatories around the world can only do one galaxy at a time.
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Massive galaxy survey confirms accelerating Universe

The Universe is definitely getting bigger, faster—and astronomers using the Anglo-Australian Telescope in NSW have confirmed it.

The WiggleZ survey looked at over 200,000 visible galaxies (middle), but also gave insights into dark matter (the green grid that deforms the gravity field) and dark energy (the purple grid). Credit: NASA/JPL-Caltech
The WiggleZ survey looked at over 200,000 visible galaxies (centre), but also gave insights into dark matter (the green grid that deforms the gravity field) and dark energy (the purple grid). Credit: NASA/JPL-Caltec

The results are now in for WiggleZ, a survey of the night sky, spanning 200,000 galaxies and billions of years of cosmic history.

“This puts a nail in it. Clearly the universe is accelerating, and clearly there is something like dark energy,” says Prof Matthew Colless, director of the Australian Astronomical Observatory and a member of the WiggleZ team.
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Mega star nursery gives birth to new knowledge

THE MASSIVE DENSE CLOUD OF HYDROGEN (SHOWN BY THE RED CONTOURS), CALLED BYF73, APPEARS TO BE COLLAPSING IN ON ITSELF DUE TO GRAVITY, FORMING HUGE PROTOSTARS (SEEN AS RED)
THE MASSIVE DENSE CLOUD OF HYDROGEN (SHOWN BY THE RED CONTOURS), CALLED BYF73, APPEARS TO BE COLLAPSING IN ON ITSELF DUE TO GRAVITY, FORMING HUGE PROTOSTARS (SEEN AS RED)

Enormous collapsing clouds of cosmic gas and dust may yield clues on how massive stars form, which is an enduring mystery of astronomy.

One such cloud, called BYF73, has been studied by a research team using CSIRO’s Mopra radio telescope. Peter Barnes, an Australian researcher working at the University of Florida in the US, leads the team. The massive hydrogen cloud is collapsing in on itself and will probably form a huge cluster of young stars. Continue reading Mega star nursery gives birth to new knowledge

Profiling and fingerprinting the stars

This story continues from Galactic archaeology— digging into the Milky Way’s past

RAVE PROJECT MANAGER, FRED WATSON, WITH THE UK SCHMIDT TELESCOPE. CREDIT: SHAUN AMY.
RAVE PROJECT MANAGER, FRED WATSON, WITH THE UK SCHMIDT TELESCOPE. CREDIT: SHAUN AMY.

But already, another Australian-led innovation in astronomical instrumentation is providing researchers with the critical information they need to understand the motions of stars within different parts of our galaxy, such as its main body, the bulging core, and the extended halo that surrounds it. Researchers are also searching for evidence of galactic cannibalism—swarms of stars that could be remnants of dwarf galaxies consumed by the Milky Way.

The innovation, called the 6dF instrument, is being used by a multinational consortium, the RAdial Velocity Experiment (RAVE), to measure the radial velocities of more than half a million stars. It is mounted on the Australian National University’s UK Schmidt Telescope at Siding Spring in New South Wales. Radial velocity is movement toward or away from the observer along the light of sight, as distinct from motion across the line of sight. The survey, which began in 2003, will be completed in 2011. Continue reading Profiling and fingerprinting the stars

Galactic archaeology— digging into the Milky Way’s past

ASTRONOMERS ARE HUNTING ‘FOSSIL’ STARS FROM GALAXIES DEVOURED BY THE MILKY WAY CREDIT: HUBBLE HERITAGE TEAM (AURA/STSCI/NASA/ESA)
ASTRONOMERS ARE HUNTING ‘FOSSIL’ STARS FROM GALAXIES DEVOURED BY THE MILKY WAY CREDIT: HUBBLE HERITAGE TEAM (AURA/STSCI/NASA/ESA)

Ken Freeman is hunting for fossils. But he’s not looking for old bones—he’s exploring the very origin and history of our Milky Way galaxy.

Conventional theory says that our galaxy grew big by engulfing smaller ones. If this is correct, stars from the original galaxies should be still identifiable within the main mass of stars via several tell-tale signs, from unusual velocities to spectral types. These stellar fossils would point to the galaxy’s birth and growth. Continue reading Galactic archaeology— digging into the Milky Way’s past

Sifting sky data

THE GIANT MAGELLAN TELESCOPE. CREDIT: GIANT MAGELLAN TELESCOPE—GMTO CORPORATION.
The Giant Magellan Telescope may use Australian Starbugs technology when it begins operating in around 2018. Credit: Giant Magellan Telescope—GMTO Corporation

Imagine an extremely large optical telescope fitted with detectors that can selectively collect light from a particular section of the telescope’s focal plane. Using revolutionary robotic technology called Starbugs, the detector will reconfigure itself in real time to collect from any particular area of the image, and will feed the data into any analytical instrument.

That’s exactly what Matthew Colless and his team at the Australian Astronomical Observatory have in mind with the development of MANIFEST (the many-instrument fibre system)—which make use of the special photonic technologies developed by Joss Bland-Hawthorn and his team at the University of Sydney. Continue reading Sifting sky data

Ten times more galaxies

THE 3.9 METRE ANGLO­-AUSTRALIAN TELESCOPE IS COLLECTING OPTICAL GALAXY DATA FOR THE GAMA SURVEY. CREDIT: BARNABY NORRIS.

A new ‘super survey’ is producing the largest database of galaxy measurements, spanning the last five billion years of cosmic history. The International Galaxy and Mass Assembly (GAMA) project is combining data from ground-and space-based observatories to measure the ‘haloes’ of dark matter that surround galaxies.

“The Cold Dark Matter (CDM) model of cosmology makes predictions about how galaxies cluster and, in many cases, collide and merge,” says Andrew Hopkins, a GAMA team member. “Our measurements of the speeds of galaxies will reveal the distribution of dark matter, and enable us to test the CDM model.”

Continue reading Ten times more galaxies