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:

Mammals were adapting from life in the trees to living on the ground before dinosaur-killing asteroid

Low LDL cholesterol levels linked to reduced risk of dementia

Thickening of the eye’s retina associated with greater risk and severity of postoperative delirium in older patients

Almost one in ten people surveyed report having been harmed by the NHS in the last three years

Enhancing light control with complex frequency excitations

New research finds novel drug target for acute myeloid leukemia, bringing hope for cancer patients

New insight into factors associated with a common disease among dogs and humans

Illuminating single atoms for sustainable propylene production

New study finds Rocky Mountain snow contamination

Study examines lactation in critically ill patients

UVA Engineering Dean Jennifer West earns AIMBE’s 2025 Pierre Galletti Award

Doubling down on metasurfaces

New Cedars-Sinai study shows how specialized diet can improve gut disorders

Making moves and hitting the breaks: Owl journeys surprise researchers in western Montana

PKU Scientists simulate the origin and evolution of the North Atlantic Oscillation

ICRAFT breakthrough: Unlocking A20’s dual role in cancer immunotherapy

How VR technology is changing the game for Alzheimer’s disease

A borrowed bacterial gene allowed some marine diatoms to live on a seaweed diet

Balance between two competing nerve proteins deters symptoms of autism in mice

Use of antifungals in agriculture may increase resistance in an infectious yeast

Awareness grows of cancer risk from alcohol consumption, survey finds

The experts that can outsmart optical illusions

Pregnancy may reduce long COVID risk

Scientists uncover novel immune mechanism in wheat tandem kinase

Three University of Virginia Engineering faculty elected as AAAS Fellows

Unintentional drug overdoses take a toll across the U.S. unequally, study finds

A step toward plant-based gelatin

ECMWF unveils groundbreaking ML tool for enhanced fire prediction

The food and fuel that farms itself

Patient- and Community-Level Characteristics Associated With RSV Vaccination

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