PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Gravitational waves 'know' how black holes grow

2013-10-23
(Press-News.org) Contact information: Helen Sim
helen.sim@csiro.au
61-293-724-251
CSIRO Australia
Gravitational waves 'know' how black holes grow Supermassive black holes: every large galaxy's got one. But how did they grow so big? A paper in the journal Science pits the front-running ideas about the growth of supermassive black holes against observational data — a limit on the strength of gravitational waves from pairs of black holes, obtained with CSIRO's 64-m Parkes radio telescope in eastern Australia. The study was jointly led by Dr Ryan Shannon, a Postdoctoral Fellow with CSIRO, and Mr Vikram Ravi, a PhD student co-supervised by the University of Melbourne (Australia) and CSIRO.

"For the first time, we've used information about gravitational waves as a tool in astrophysics," said Dr Shannon.

"It's a powerful new tool. These black holes are very hard to observe directly, so this is a new chapter in astronomy."

"One model for black-hole growth has failed our test and we're painting the others into a corner. They may not break, but they'll have to bend," said Mr Ravi.

Einstein predicted gravitational waves — ripples in space-time, generated by bodies changing speed or direction. Bodies, for instance, such as pairs of black holes orbiting each other.

When galaxies merge, their resident central black holes are doomed to meet. They first waltz together then enter a desperate embrace and merge.

"Theorists predict that towards the end of this dance they're growling out gravitational waves at a frequency we're set up to detect," Dr Shannon said.

Played out again and again across the Universe, such encounters create a background of gravitational waves, like the noise from a restless crowd.

Astronomers have been searching for gravitational waves with the Parkes radio telescope and a set of 20 small, spinning stars called pulsars.

Pulsars act as extremely precise clocks in space. We measure when their pulses arrive on Earth to within a tenth of a microsecond.

As gravitational waves roll through an area of space-time, they temporarily swell or shrink the distances between objects in that region. "That can alter the arrival time of the pulses on Earth," said Dr Michael Keith of the University of Manchester in the UK.

The Parkes Pulsar Timing Array (PPTA) project and an earlier collaboration between CSIRO and Swinburne University together provide nearly 20 years' worth of timing data.

"We haven't yet detected gravitational waves outright, but we're now into the right ballpark to do so," said the project leader, CSIRO's Dr George Hobbs.

Combining pulsar-timing data from Parkes with that from other telescopes in Europe and the USA — a total of about 50 pulsars — should give us the accuracy to detect gravitational waves "within ten years", he said.

Meanwhile, the PPTA results are showing us how low the background rate of gravitational waves is.

The strength of the gravitational wave background depends on how often supermassive black holes spiral together and merge, how massive they are, and how far away they are. So if the background is low, that puts a limit on one or more of those factors.

Armed with the PPTA data, the researchers tested four models of black-hole growth. They effectively ruled out black holes gaining mass only through mergers, but the other three models "are still in the game", said Dr Sarah Burke-Spolaor of California Institute of Technology (Caltech).

### END


ELSE PRESS RELEASES FROM THIS DATE:

There's gold in them thar trees

2013-10-23
There's gold in them thar trees Eucalyptus trees - or gum trees as they are know - are drawing up gold particles from the earth via their root system and depositing it their leaves and branches. Scientists from CSIRO made the discovery and have published their findings ...

The hitchhiker antigen: Cause for concern?

2013-10-23
The hitchhiker antigen: Cause for concern? Since antibodies first attained prominence as research reagents in modern biological science labs, researchers have been perplexed as to why one production lot can differ significantly from the next, ...

How are Open Access and MOOCS disrupting the academic community in different ways?

2013-10-23
How are Open Access and MOOCS disrupting the academic community in different ways? New article in SAGE Open compares and contrasts the disruptive tensions of open-access publishing with MOOCs Los Angeles, CA (October 23, 2013) Supporters of open academic content ...

New eye treatment effective in laboratory tests

2013-10-23
New eye treatment effective in laboratory tests Promising new approach may lead to treatments for common eye diseases like neovascular macular degeneration and diabetic retinopathy LA JOLLA, CA – October 23, 2013 – A promising technique for treating human eye disease ...

Changes in epigenetic DNA functions reveal how diabetes predisposes individuals to Alzheimer's

2013-10-23
Changes in epigenetic DNA functions reveal how diabetes predisposes individuals to Alzheimer's Mount Sinai researchers hope to exploit findings to develop novel preventive and treatment strategies for Alzheimer's disease New ...

Swiss private banking in clinch with high cost level

2013-10-23
Swiss private banking in clinch with high cost level For the international wealth management industry, 2012 was a more benign year than the harsh 2011. Due to favorable stock and bond markets the volumes of managed funds increased, though not returning to pre-crisis ...

The molecular clock of the common buzzard

2013-10-23
The molecular clock of the common buzzard Bielefeld biologists reveal the influence of genes on dispersal behavior This news release is available in German. Be it hibernation or the routes of migratory birds: all animal behaviour that is subject to annual ...

Nanopore opens new cellular doorway for drug transport

2013-10-23
Nanopore opens new cellular doorway for drug transport A living cell is built with barriers to keep things out – and researchers are constantly trying to find ways to smuggle molecules in.‬ ‪Professor Giovanni Maglia (Biochemistry, Molecular and Structural ...

New software traces origins of genetic disorders 20 times more accurately

2013-10-23
New software traces origins of genetic disorders 20 times more accurately In a bioinformatics breakthrough, iMinds – STADIUS – KU Leuven researchers have successfully applied advanced artificial intelligence to enable the automated analysis of huge amounts of ...

Insights into how TB tricks the immune system could help combat the disease

2013-10-23
Insights into how TB tricks the immune system could help combat the disease Researchers have identified a potential way to manipulate the immune system to improve its ability to fight off tuberculosis (TB). TB is a major problem for both humans and ...

LAST 30 PRESS RELEASES:

Signs identified that precede sudden arrhythmic death syndrome in young people

Discovery of bacteria's defence against viruses becomes a piece of the puzzle against resistance

Pre-eclampsia is associated with earlier onset and higher incidence of cardiovascular risk factors

Warwick astronomers discover doomed pair of spiralling stars on our cosmic doorstep

Soil conditions significantly increase rainfall in world’s megastorm hotspots

NK cells complexed with bispecific antibody yield high response rates in patients with lymphoma

Planetary health diet and mediterranean diet associated with similar survival and sustainability benefits

Singapore launches national standard to validate antimicrobial disinfectant products

Molecular stool test could improve detection of tuberculosis in adults with HIV

Suspected fibrocartilaginous embolus in Asian small-clawed otter (Aonyx cinereus)

Enhancing heat transfer using the turbulent flow of viscoelastic fluids

Exercise as an anti-ageing intervention to avoid detrimental impact of mental fatigue

UMass Amherst Nursing Professor Emerita honored as ‘Living Legend’

New guidelines aim to improve cystic fibrosis screening

Picky eaters by day, buffet by night: Butterfly, moth diets sync to plant aromas

Pennington Biomedical’s Dr. Leanne Redman honored with the E. V. McCollum Award from the American Society for Nutrition

CCNY physicists uncover electronic interactions mediated via spin waves

Researchers’ 3D-printing formula may transform future of foam

Nurture more important than nature for robotic hand

Drug-delivering aptamers target leukemia stem cells for one-two knockout punch

New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed

New sea grant report helps great lakes fish farmers navigate aquaculture regulations

Strain “trick” improves perovskite solar cells’ efficiency

How GPS helps older drivers stay on the roads

Estrogen and progesterone stimulate the body to make opioids

Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation

Machine learning helps construct an evolutionary timeline of bacteria

Cellular regulator of mRNA vaccine revealed... offering new therapeutic options

Animal behavioral diversity at risk in the face of declining biodiversity

Finding their way: GPS ignites independence in older adult drivers

[Press-News.org] Gravitational waves 'know' how black holes grow