Split-personality elliptical galaxy holds a hidden spiral

October 22, 2012
The giant elliptical galaxy M87 shows a split personality because it hides a gaseous spiral at its core. When M87 collided with a spiral galaxy 300 million years ago, it slurped up the spiral's gases, which formed a new spiral inside the larger galaxy. Credit: ESO

(Phys.org)—Most big galaxies fit into one of two camps: pinwheel-shaped spiral galaxies and blobby elliptical galaxies. Spirals like the Milky Way are hip and happening places, with plenty of gas and dust to birth new stars. Ellipticals are like cosmic retirement villages, full of aging residents in the form of red giant stars. Now, astronomers have discovered that one well-known elliptical has a split personality. Centaurus A is hiding a gassy spiral in its center.

"No other is known to have spiral arms," said lead author Daniel Espada ( of Japan & Harvard-Smithsonian Center for Astrophysics). "Centaurus A may be an old galaxy, but it's still very young at heart."

Centaurus A isn't your typical elliptical to begin with. Its most striking feature is a dark dust lane across its middle - a sign that it swallowed a spiral galaxy about 300 million years ago.

Centaurus A slurped that galaxy's gases down, forming a disk that we see nearly edge on. From our point of view, any features in that disk have been hidden by the intervening dust.

To tease out the disk's structure, Espada and his colleagues used the sharp vision of the Smithsonian's Submillimeter Array. This radio telescope can see through dust to pick up signals from naturally occurring carbon monoxide gas. By mapping the gas, the team unveiled two distinct spiral arms within the galaxy's core.

These gaseous tendrils have sizes and shapes similar to spiral arms in galaxies like the . Also like the Milky Way's spiral arms, they are forming new generations of stars.

"Centaurus A has been given a new lease on life by that past merger," said Espada.

Computer simulations suggest that the spiral features might endure for hundreds of millions of years to come.

Although Centaurus A is the first elliptical galaxy found to have , it may not be the last. Since it's only 12 million light-years away, it's relatively nearby and easy to study. The Atacama Large Millimeter/submillimeter Array (ALMA) potentially can find more split-personality galaxies with its improved radio "vision."

"We definitely will use ALMA to search for other objects that are similar to Centaurus A," added Espada.

These findings were published in The Astrophysical Journal Letters and are available online.

Explore further: A new, distant arm of the Milky Way galaxy

Related Stories

A new, distant arm of the Milky Way galaxy

June 13, 2011

(PhysOrg.com) -- Our Milky Way galaxy, like other spiral galaxies, has a disk with sweeping arms of stars, gas, and dust that curve around the galaxy like the arms of a huge pinwheel.

A spiral galaxy in Hydra

April 9, 2012

(Phys.org) -- This image from the NASA/ESA Hubble Space Telescope shows NGC 4980, a spiral galaxy in the southern constellation of Hydra. The shape of NGC 4980 appears slightly deformed, something which is often a sign of ...

Spitzer finds galaxy with split personality

April 25, 2012

(Phys.org) -- While some galaxies are rotund and others are slender disks like our spiral Milky Way, new observations from NASA's Spitzer Space Telescope show that the Sombrero galaxy is both. The galaxy, which is a round ...

Hubble sees a spiral within a spiral

May 28, 2012

(Phys.org) -- NASA's Hubble Space Telescope captured this image of the spiral galaxy known as ESO 498-G5. One interesting feature of this galaxy is that its spiral arms wind all the way into the center, so that ESO 498-G5's ...

ALMA turns its eyes to Centaurus A

May 31, 2012

(Phys.org) -- A new image of the galaxy Centaurus A, made with the Atacama Large Millimeter/submillimeter Array (ALMA), shows how the observatory allows astronomers to see through the opaque dust lanes that obscure the galaxy's ...

Recommended for you

Hubble image: Stormy seas in Sagittarius

July 30, 2015

Some of the most breathtaking views in the Universe are created by nebulae - hot, glowing clouds of gas. This new NASA/ESA Hubble Space Telescope image shows the centre of the Lagoon Nebula, an object with a deceptively tranquil ...

New Horizons data hint at underground ocean

July 30, 2015

Pluto wears its heart on its sleeve, and that has scientists gleaning intriguing new facts about its geology and climate. Recent data from NASA's New Horizons probe—which passed within 7,800 miles of the surface on July ...

Unusual red arcs spotted on icy Saturn moon Tethys

July 30, 2015

Like graffiti sprayed by an unknown artist, unexplained arc-shaped, reddish streaks are visible on the surface of Saturn's icy moon Tethys in new, enhanced-color images from NASA's Cassini spacecraft.

Dense star clusters shown to be binary black hole factories

July 29, 2015

The coalescence of two black holes—a very violent and exotic event—is one of the most sought-after observations of modern astronomy. But, as these mergers emit no light of any kind, finding such elusive events has been ...

8 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Tuxford
1 / 5 (15) Oct 22, 2012
Astronomers spewing merger nonsense propoganda again. Centaurus A is simply growing from within from a spiral into an elliptical. This is the standard path of galactic evolution in LaViolette's SubQuantum Kinectics 'continuous creation' model.
cantdrive85
1 / 5 (14) Oct 22, 2012
"Students using astrophysical textbooks remain essentially ignorant of even the existence of plasma concepts, despite the fact that some of them have been known for half a century. The conclusion is that astrophysics is too important to be left in the hands of astrophysicists who have gotten their main knowledge from these textbooks. Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory."
[Lamenting the traditional neglect of plasma physics]
— Hannes Alfvén

Hence, we get some nonsensical "story" such as above! Anthony Peratt's particle in cell simulations of interacting plasmoids describes many different types of galaxy formations, this one included.
Bowler_4007
5 / 5 (7) Oct 22, 2012
Astronomers spewing merger nonsense propoganda again. Centaurus A is simply growing from within from a spiral into an elliptical. This is the standard path of galactic evolution in LaViolette's SubQuantum Kinectics 'continuous creation' model.

if it grew from within from spiral to elliptical then center would elliptical and the outside spiral because the ellipse would be taking over from the inside
vidyunmaya
1 / 5 (8) Oct 23, 2012
sub: Blocked Ego-How can Science Advance ?
Open Mind approach helps the Image in right perspective.
Universal Plasma Energy model-UPE-IEEE-ICOPS 1991 -paper by me identifies the sequence. The data of the image confirms the Flow Sequence while the Interpretations by dog-matic astronomers block
even the next generation to digest or interact.
How can Nature help ! Only by on-set of phenomena
Vidyardhicosmology.blogspot.com

CrooklynBoy
2.8 / 5 (4) Oct 23, 2012
Can one of you tell me if these spiral galaxy's are spinning, and if they are, why? Why a pinwheel? What is driving the rotation? The black hole in the center? Thanx.
kevinrtrs
1 / 5 (9) Oct 23, 2012
Also like the Milky Way's spiral arms, they are forming new generations of stars.

This is sheer make-belief and utter, rife speculation.

There is currently no observational evidence to support ANY new star formation whatsoever.
All that exists is a hollow theory according to which stars should "form" from dust/gaseous clouds.
BUt unfortunately for the proponents, no such star formation has EVER been observed.
I wish people would stop the outright false statements and put in the proper qualification of "it is thought or believed that..." As it stands now, it is simply an outright falsehood.

A simple calculation using the so-called estimated time of existence of the universe plus the number of stars in it gives an estimated required rate of "star formation" so high we'd be able to count them off every day. Right now, NOTHING has been spotted for all time of watching the skies. Nothing. Nada. Zip. Period.
El_Nose
5 / 5 (3) Oct 23, 2012
with out looking it up I can tell you that yes it is spinning. All galaxies spin regardless of type. If it did not spin everything would just be falling towards a gravitational center. Kepler's Laws explain the rotation. Blackhole - probably, but I have not read anything in the way of confirmation

I think kev is trying to say simulations do not match observations ???
Kron
1 / 5 (3) Oct 26, 2012
el_nose, each star creates a solar wind (particles being blown into space). Heliospheres keep stars spaced out and stop a galactic gravitational collapse. It is the solar wind which gives planets spins and orbits, too. If the solar wind ceased the planets would slowly begin spiraling into the Sun (there would be nothing pushing them away, no counterbalance to the gravitational pull).

Galaxies spin because the wind generated by individual stars have set them into motion. If galactic spin were removed, it would just start back up again. There would be no gravitational collapse you describe.

Galactic spin is a result of the energy output of stars. Order from chaos. The chaotic energy output from individual stars structures into a common energetic flow. This is the spiral. Not all galaxies are found in an ordered state, but with time fluid dynamics prevail.

Natures reverse entropy. Disorder leading to order.

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.