Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy.

"Without GALEX's ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system," said lead scientist Rafael Eufrasio, a research assistant at NASA's Goddard Space Flight Center in Greenbelt, Md., who is a doctoral student at Catholic University of America in Washington. He presented the findings Thursday at the American Astronomical Society meeting in Long Beach, Calif.

The galaxy's unusual size and appearance stem from its interaction with a much smaller disk galaxy named IC 4970, which has only about one-fifth the mass of NGC 6872. The odd couple is located 212 million light-years from Earth in the southern constellation Pavo.

Astronomers think large galaxies, including our own, grew through mergers and acquisitions -- assembling over billions of years by absorbing numerous smaller systems.

Intriguingly, the gravitational interaction of NGC 6872 and IC 4970 may have done the opposite, spawning what may develop into a new small galaxy.

"The northeastern arm of NGC 6872 is the most disturbed and is rippling with star formation, but at its far end, visible only in the ultraviolet, is an object that appears to be a tidal dwarf galaxy similar to those seen in other interacting systems," said team member Duilia de Mello, a professor of astronomy at Catholic University.

The tidal dwarf candidate is brighter in ultraviolet than other regions of the galaxy, a sign it bears a rich supply of hot young stars less than 200 million years old.

Astronomers have spotted the largest known spiral galaxy - by accident.

A team was looking through data from the Galaxy Evolution Explorer (Galex) satellite for star-forming regions around a galaxy called NGC 6872.

But they were shocked to see a vast swathe of ultraviolet light from young stars, indicating that the galaxy is actually big enough to accommodate five of our Milky Way galaxies within it.

The find was reported at the American Astronomical Society meeting in the US.

NGC 6872, a galaxy about 212 million light-years away in the constellation Pavo, was already known to be among the largest spiral galaxies.

Near it sits a lens-shaped or lenticular galaxy called IC 4970, which appears to have crashed through the spiral in recent astronomical times.

Rafael Eufrasio of the Catholic University of America and Nasa's Goddard Space Flight Center and colleagues from the University of Sao Paulo in Brazil and the European Southern Observatory in Chile were interested in a number of regions away from the galaxy.

"I was not looking for the largest spiral - it just came as a gift," Mr Eufrasio told BBC News.

Galex - a space telescope designed to search for the ultraviolet light that newly born stars put out - hinted that NGC 6872 was made much larger in size by the collision.

The team went on to use data from a range of other telescopes including the Very Large Telescope, the Two Micron All-Sky Survey and the Spitzer space telescope - each of which sees in a particular set of colours, in turn evidencing stars of varying ages.

They found the youngest stars in the outer reaches of the galaxy's enormous spiral arms, getting progressively older toward the centre.

That suggests a wave of star formation that travelled down the arms, set off by the collision with IC 4970, with the newest stellar neighbourhoods pushing the galaxy into the top spot in terms of size.

"It's been known to be among the largest for two decades, but it's much larger than we thought," explained Mr Eufrasio.

"The galaxy that collided with the [central disc of NGC 6872] splashed stars all over the place - 500,000 light years away."

Originally posted by theabsolutetruth
More exciting finds from the world of Astronomy, this galaxy is larger than thought.

www.jpl.nasa.gov...

Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy.

"Without GALEX's ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system," said lead scientist Rafael Eufrasio, a research assistant at NASA's Goddard Space Flight Center in Greenbelt, Md., who is a doctoral student at Catholic University of America in Washington. He presented the findings Thursday at the American Astronomical Society meeting in Long Beach, Calif.

The galaxy's unusual size and appearance stem from its interaction with a much smaller disk galaxy named IC 4970, which has only about one-fifth the mass of NGC 6872. The odd couple is located 212 million light-years from Earth in the southern constellation Pavo.

Astronomers think large galaxies, including our own, grew through mergers and acquisitions -- assembling over billions of years by absorbing numerous smaller systems.

Intriguingly, the gravitational interaction of NGC 6872 and IC 4970 may have done the opposite, spawning what may develop into a new small galaxy.

"The northeastern arm of NGC 6872 is the most disturbed and is rippling with star formation, but at its far end, visible only in the ultraviolet, is an object that appears to be a tidal dwarf galaxy similar to those seen in other interacting systems," said team member Duilia de Mello, a professor of astronomy at Catholic University.

The tidal dwarf candidate is brighter in ultraviolet than other regions of the galaxy, a sign it bears a rich supply of hot young stars less than 200 million years old.

www.bbc.co.uk...

Astronomers have spotted the largest known spiral galaxy - by accident.

A team was looking through data from the Galaxy Evolution Explorer (Galex) satellite for star-forming regions around a galaxy called NGC 6872.

But they were shocked to see a vast swathe of ultraviolet light from young stars, indicating that the galaxy is actually big enough to accommodate five of our Milky Way galaxies within it.

The find was reported at the American Astronomical Society meeting in the US.

NGC 6872, a galaxy about 212 million light-years away in the constellation Pavo, was already known to be among the largest spiral galaxies.

Near it sits a lens-shaped or lenticular galaxy called IC 4970, which appears to have crashed through the spiral in recent astronomical times.

Rafael Eufrasio of the Catholic University of America and Nasa's Goddard Space Flight Center and colleagues from the University of Sao Paulo in Brazil and the European Southern Observatory in Chile were interested in a number of regions away from the galaxy.

"I was not looking for the largest spiral - it just came as a gift," Mr Eufrasio told BBC News.

Galex - a space telescope designed to search for the ultraviolet light that newly born stars put out - hinted that NGC 6872 was made much larger in size by the collision.

The team went on to use data from a range of other telescopes including the Very Large Telescope, the Two Micron All-Sky Survey and the Spitzer space telescope - each of which sees in a particular set of colours, in turn evidencing stars of varying ages.

They found the youngest stars in the outer reaches of the galaxy's enormous spiral arms, getting progressively older toward the centre.

That suggests a wave of star formation that travelled down the arms, set off by the collision with IC 4970, with the newest stellar neighbourhoods pushing the galaxy into the top spot in terms of size.

"It's been known to be among the largest for two decades, but it's much larger than we thought," explained Mr Eufrasio.

"The galaxy that collided with the [central disc of NGC 6872] splashed stars all over the place - 500,000 light years away."

edit on 11-1-2013 by theabsolutetruth because: (no reason given)

Originally posted by CrypticSouthpaw
reply to post by Chrisfishenstein

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iv often stressed this point. I think the galaxy just goes on and on and on and on like one of those creepy animated avatars.