Giant filament structures give a rare insight into galaxy cluster evolution

Apr 05, 2006
The RGB image of the BIG group
The RGB image of the BIG group. Blue is Halpha Net band, Red is r' band and Green is Halpha on band.

A new image of the centre of a cluster of galaxies has revealed massive filamentary structures that give a rare insight into the evolution of galaxy clusters.

“The star forming regions in the cluster that we’d observed previously were just the tip of the iceberg. We’ve now observed filaments of gas streaming out from these regions that are approximately 490 thousand light years across. The gaseous trails mark the path of galaxies travelling at high speed through the cluster.

The origin of these unique features is still a matter for debate, but we think the combined action of tidal forces among galaxies in the cluster and of ram-pressure by the ambient medium caused the galaxies to fragment and blast out the ionized gas,” said Dr Luca Cortese, who is presenting the results at the Royal Astronomical Society’s National Astronomy Meeting on 5th April.

An international team, lead by Dr Cortese, studied the physical properties of a compact group that is falling towards the centre of a cluster of galaxies known as Abell1367 at a rate of 1700 km/s. The group, which was discovered in 2002, has the highest density of star forming objects ever observed in local clusters. It contains two giant galaxies, at least ten dwarf galaxies or extragalactic clouds of gas and over a billion solar masses of diffuse gas filaments.

Scientists believe that clusters of galaxies are formed from the accretion of compact groups like the one observed in Abell1367. Formation of clusters of galaxies peaked 5 billion years ago. Now the rate is at least three times lower and it will slow dramatically due to the effects of the acceleration of the Universe. The Abell1367 group is particularly important as it is only 300 million light years from Earth – ‘local’ in terms of the Universe – and so the scientists can see the processes at work in unprecedented detail. Dr Cortese explains, “The physical processes seen here are typical of young clusters, found far away in space and a long time ago. To really understand what’s going on, we need a close up view. This is the first time we have found an example of a galaxy group mid-way through its transformation that is close enough for us to have a really good look at the structures surrounding the galaxies.”

The results suggest that at least part of the changes to the structure of cluster galaxies that took place in earlier epochs happened very differently to ones observed in today’s clusters. In today’s clusters of galaxies, the galaxies are travelling faster than in the infalling groups, which means that gravitational interactions between galaxies happen much faster.

The study was carried out using the Italian National Telescope Galileo in La Palma in April 2004 and February 2006.

The results of this study are accepted for publication on Astronomy and Astrophysics.

Source: Royal Astronomical Society

Explore further: Why is Venus so horrible?

add to favorites email to friend print save as pdf

Related Stories

People finding their 'waze' to once-hidden streets

3 hours ago

When the people whose houses hug the narrow warren of streets paralleling the busiest urban freeway in America began to see bumper-to-bumper traffic crawling by their homes a year or so ago, they were baffled.

Identity theft victims face months of hassle

3 hours ago

As soon as Mark Kim found out his personal information was compromised in a data breach at Target last year, the 36-year-old tech worker signed up for the retailer's free credit monitoring offer so he would ...

Observers slam 'lackluster' Lima climate deal

3 hours ago

A carbon-curbing deal struck in Lima on Sunday was a watered-down compromise where national intransigence threatened the goal of a pact to save Earth's climate system, green groups said.

Your info has been hacked. Now what do you do?

3 hours ago

Criminals stole personal information from tens of millions of Americans in data breaches this past year. Of those affected, one in three may become victims of identity theft, according to research firm Javelin. ...

New Bond script stolen in Sony hack

3 hours ago

An "early version" of the screenplay for the new James Bond film was the latest victim of a massive hacking attack on Sony Pictures Entertainment, its producers said in a statement on their website Sunday.

Ag-tech could change how the world eats

9 hours ago

Investors and entrepreneurs behind some of the world's newest industries have started to put their money and tech talents into farming - the world's oldest industry - with an audacious agenda: to make sure there is enough ...

Recommended for you

SDO captures images of two mid-level flares

9 hours ago

The sun emitted a mid-level flare on Dec. 18, 2014, at 4:58 p.m. EST. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts ...

Why is Venus so horrible?

16 hours ago

Venus sucks. Seriously, it's the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you ...

Image: Christmas wrapping the Sentinel-3A antenna

19 hours ago

The moment a team of technicians, gowned like hospital surgeons, wraps the Sentinel-3A radar altimeter in multilayer insulation to protect it from the temperature extremes found in Earth orbit.

Video: Flying over Becquerel

19 hours ago

This latest release from the camera on ESA's Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.