Sky survey provides clues to how they change over time.
The direction in which a galaxy spins depends on its mass, researchers have found.
A team of astrophysicists analysed 1418 galaxies and found that small ones are likely to spin on a different axis to large ones. The rotation was measured in relation to each galaxy’s closest “cosmic filament” – the largest structures in the universe.
Filaments are massive thread-like formations, comprising huge amounts of matter – including galaxies, gas and, modelling implies, dark matter. They can be 500 million light years long but just 20 million light years wide. At their largest scale, the filaments divide the universe into a vast gravitationally linked lattice interspersed with enormous dark matter voids.
CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) telescope is already booked out for much of its first five years of data gathering, even before it formally begins early operations in 2013.
More than 400 astronomers from over a dozen nations have already signed up to look for pulsars, measure cosmic magnetic fields, and study millions of galaxies.
Far outback in Western Australia, 32 tiles—flat, stationary sensors—each carrying 16 dipole antennas have begun collecting scientific data.
These first tiles will ultimately form part of a much bigger array of 512 tiles, the Murchison Widefield Array (MWA)—Australia’s second Square Kilometre Array (SKA) demonstrator project. Like CSIRO’s Australian SKA Pathfinder (ASKAP), the MWA is being built at the remote, radio-quiet Murchison Radio-astronomy Observatory (MRO). Continue reading Telescope of tiles→
Over aeons of time cosmic gas comes together, stars begin to form, supernovae explode, galaxies collide. And computational astronomers can watch it all unfold inside a supercomputer. That’s the kind of work post-doctoral fellows Rob Crain and Greg Poole are doing at the Swinburne Centre for Astrophysics and Supercomputing. Continue reading Supercomputers bring theory to life→
At the centre of a nearby galaxy lurks an object of huge interest, a super-massive black hole. CSIRO scientists have used their radio telescopes to take a picture of the galaxy surrounding it, a task some thought could not be done, because of the sheer size and radio brightness of the scene. The image of Centaurus A took about 1,200 hours of observations and a further 10,000 hours of computer processing to put together, but the work is already beginning to bear fruit.
“We didn’t generate this image just to make a pretty picture,” says lead scientist Ilana Feain of CSIRO Astronomy and Space Science. “We want to understand in detail how the energy from super-massive black holes influences the formation and evolution of their host galaxies.” Continue reading Recording the impact of a super-massive black hole→
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→
Cracking the puzzle of unusual molecules in deep space that absorb some wavelengths of starlight is like unlocking the secrets of the Rosetta Stone, according to Rob Sharp of the Australian National University’s Research School of Astronomy and Astrophysics. “It’s the longest-standing problem in astronomical spectroscopy,” he says.
Using the Gemini South telescope in Chile, a team of astronomers led by Joss Bland-Hawthorn of the University of Sydney revealed the faint, outer regions of the galaxy called NGC 300, showing that the galaxy is at least twice the size as thought previously. The findings suggest that our own Milky Way galaxy could also be bigger than the textbooks say.
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.”