Spitzer finds galaxy with split personality

Apr 25, 2012
The infrared vision of NASA's Spitzer Space Telescope has revealed that the Sombrero galaxy -- named after its appearance in visible light to a wide-brimmed hat -- is in fact two galaxies in one. Image credit: NASA/JPL-Caltech

(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 elliptical galaxy with a thin disk embedded inside, is one of the first known to exhibit characteristics of the two different types. The findings will lead to a better understanding of galaxy evolution, a topic still poorly understood.

"The Sombrero is more complex than previously thought," said Dimitri Gadotti of the European Southern Observatory in Chile and lead author of a new paper on the findings appearing in the . "The only way to understand all we know about this galaxy is to think of it as two galaxies, one inside the other."

The Sombrero galaxy, also known as NGC 4594, is located 28 million light-years away in the . From our viewpoint on Earth, we can see the thin edge of its flat disk and a central bulge of stars, making it resemble a wide-brimmed hat. Astronomers do not know whether the Sombrero's disk is shaped like a ring or a spiral, but agree it belongs to the disk class.

"Spitzer is helping to unravel secrets behind an object that has been imaged thousands of times," said Sean Carey of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "It is intriguing Spitzer can read the fossil record of events that occurred billions of years ago within this beautiful and archetypal galaxy."

New observations from NASA's Spitzer Space Telescope reveal the Sombrero galaxy is not simply a regular flat disk galaxy of stars as previously believed, but a more round elliptical galaxy with a flat disk tucked inside.

Spitzer captures a different view of the galaxy than visible-light telescopes. In visible views, the galaxy appears to be immersed in a glowing halo, which scientists had thought was relatively light and small. With Spitzer's , a different view emerges. Spitzer sees old stars through the dust and reveals the halo has the right size and mass to be a .

While it is tempting to think the giant elliptical swallowed a spiral disk, astronomers say this is highly unlikely because that process would have destroyed the disk structure. Instead, one scenario they propose is that a giant elliptical galaxy was inundated with gas more than nine billion years ago. Early in the history of our universe, networks of gas clouds were common, and they sometimes fed growing galaxies, causing them to bulk up. The gas would have been pulled into the galaxy by gravity, falling into orbit around the center and spinning out into a flat disk. Stars would have formed from the gas in the disk.

"This poses all sorts of questions," said Rubén Sánchez-Janssen from the , co-author of the study. "How did such a large disk take shape and survive inside such a massive elliptical? How unusual is such a formation process?"

Researchers say the answers could help them piece together how other evolve. Another galaxy, called Centaurus A, appears also to be an elliptical galaxy with a disk inside it. But its disk does not contain many stars. Astronomers speculate that Centaurus A could be at an earlier stage of evolution than the Sombrero and might eventually look similar.

The findings also answer a mystery about the number of globular clusters in the Sombrero galaxy. Globular clusters are spherical nuggets of old stars. Ellipticals typically have a few thousand, while spirals contain a few hundred. The Sombrero has almost 2,000, a number that makes sense now but had puzzled astronomers when they thought it was only a disk galaxy.

Explore further: Planet-forming lifeline discovered in a binary star system

Related Stories

Spitzer sees spider web of stars

Jul 21, 2011

(PhysOrg.com) -- Those aren't insects trapped in a spider's web -- they're stars in our own Milky Way galaxy, lying between us and another spiral galaxy called IC 342. NASA's Spitzer Space Telescope captured ...

Amazing Andromeda Galaxy

Oct 03, 2006

The many "personalities" of our great galactic neighbor, the Andromeda galaxy, are exposed in this new composite image from NASA's Galaxy Evolution Explorer and the Spitzer Space Telescope.

Spitzer captures infrared rays from a sunflower

Mar 04, 2011

(PhysOrg.com) -- The various spiral arm segments of the Sunflower galaxy, also known as Messier 63, show up vividly in this image taken in infrared light by NASA's Spitzer Space Telescope. Infrared light is ...

Hubble Illuminates Cluster of Diverse Galaxies

Feb 06, 2007

This image from NASA's Hubble Space Telescope shows the diverse collection of galaxies in the cluster Abell S0740 that is over 450 million light-years away in the direction of the constellation Centaurus.

Spider Web of Stars in Galaxy IC 342

Mar 20, 2012

(PhysOrg.com) -- Looking like a spider's web swirled into a spiral, Galaxy IC 342 presents its delicate pattern of dust in this image from NASA's Spitzer Space Telescope. Seen in infrared light, faint starlight ...

A new, distant arm of the Milky Way galaxy

Jun 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.

Recommended for you

When did galaxies settle down?

1 hour ago

Astronomers have long sought to understand exactly how the universe evolved from its earliest history to the cosmos we see around us in the present day. In particular, the way that galaxies form and develop ...

Image: Hubble views the whirling disk of NGC 4526

2 hours ago

This neat little galaxy is known as NGC 4526. Its dark lanes of dust and bright diffuse glow make the galaxy appear to hang like a halo in the emptiness of space in this image from the NASA/ESA Hubble Space ...

Planet-forming lifeline discovered in a binary star system

20 hours ago

Scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) have detected a streamer of dust and gas flowing from a massive outer disk toward the inner reaches of a binary star system. This never-before-seen ...

Astronomy & Astrophysics: Planck 2013 results

Oct 29, 2014

Astronomy & Astrophysics is publishing a special feature of 31 articles describing the data gathered by Planck over 15 months of observations and released by ESA and the Planck Collaboration in March 2013. ...

User comments : 11

Adjust slider to filter visible comments by rank

Display comments: newest first

kevinrtrs
1 / 5 (9) Apr 25, 2012
galaxy evolution, a topic still poorly understood

Maybe it should be stated as galaxy "formation". Because that is really, totally NOT understood at all. All that exists is speculation, wild speculation and finally cosmogony.
To overcome that glaring fact, people make statements like this:
Early in the history of our universe, networks of gas clouds were common, and they sometimes fed growing galaxies, causing them to bulk up. The gas would have been pulled into the galaxy by gravity, falling into orbit around the center and spinning out into a flat disk. Stars would have formed from the gas in the disk.
This is supposed to show facts and truth but simply hide the ignorant speculation behind it all. At least they do admit that there's speculation involved:
Astronomers speculate that Centaurus A could be at an earlier stage of evolution than the Sombrero

It's just a pity then that the speculation gets passed off as truth.
Skepticus
3.7 / 5 (6) Apr 25, 2012
Okaay.. The "Intelligent Designer" created it out of boredom and lack of overtime pay to impress his Intelligent Creator for more pay.
Rectinol
not rated yet Apr 25, 2012
do we need ads interspersed through the blurb? - eww could confuse a stupid person.
Rectinol
not rated yet Apr 25, 2012
... also you should sell your telescopes and invest in John K Hutchison ... then you can fly there for a closer peek ...
Tuxford
1 / 5 (5) Apr 25, 2012
Simple. This is a galaxy growing from a spiral into an elliptical, as in LaViolette's continuous creation model, where ellipticals are the final stage of galactic evolution. As such, the galaxy grows from ejections of new matter from the active core mother star. A higher population of clusters would be expected in the older galaxies, as is observed in the giant ellipticals. The evidence is adding up. How much longer will the evidence be ignored?
thingumbobesquire
1 / 5 (1) Apr 25, 2012
Dare I say hats off?
vidyunmaya
1 / 5 (2) Apr 25, 2012
sub: Sombrero galaxy
This structure wakes up Astronomers to Cosmology Studies.
useful information:The findings also answer a mystery about the number of globular clusters in the Sombrero galaxy. Globular clusters are spherical nuggets of old stars. Ellipticals typically have a few thousand, while spirals contain a few hundred. The Sombrero has almost 2,000, a number that makes sense now but had puzzled astronomers when they thought it was only a disk galaxy.
The image is a welcome feature included in my books. for detailed Explanations- see projections in my books-see copyrights and ISBN alloted recently in India
http://vidyardhic...ion.html
MarkyMark
5 / 5 (6) Apr 26, 2012
@ Tuxford - It will continue to be ignored untill it has some good evidence to back it up. Right now it shares the same level of proovabilaty as Aither theory Neutron Repulsion and Scientology!
Mastoras
not rated yet Apr 30, 2012
All that exists is speculation, wild speculation and finally cosmogony.


I think you dont seem to understand not only what you've read, but also who wrote it.

What you read is a news article. When people write news articles, they take many things for granted, they may even simplify things, and what they write is in no way a complete history of science, or astronomy in this case.

Not being a complete history of astronomy, means that they dont tell you all the evidence and all the thinking that leads to the statements that are made. Please, PLEASE, stop perceiving this as any kind of discovery for the grand foolish thing that is science. Instead, read some books.

And also: what you've read is not the opinion of any scientist, because this is not a scholarly forum. ... [to be continued]
-.
Mastoras
not rated yet Apr 30, 2012
And also: what you've read is not the opinion of any scientist, because this is not a scholarly forum. In my understanding, this is a forum aiming to inform on recent science news in a rather popularizing manner. After all, many of us reading here, are not specialists, but simply interested in science.

So, you can in no way say that what you read is the opinion "of scientists", because there is no such general thing. If you want to read the opinion of scientists you should look for it.

And also: if you want to say something to the scientists, this is not the place to do it. Write an article, show it to some friends, take their opinion, correct your article, and repeat as necessary. Then put it online somewhere (arxiv.org is fine), and wait for people to read it. But there is no reason to bring your opinion again and again, in all related and unrelated news.
-.
Origin
1 / 5 (2) Apr 30, 2012
In dense aether model the young galaxies are spherical, as they're driven with intensive light and neutrino flux from underlying white hole (called the active galactic nuclei or quasar). When the central object will lose its mass, it develops the polar jets (the event horizon at the central object becomes closed at the equatorial plane) and the central disk becomes flattened like the pancake. When the event horizon of central black hole gets closed completely, then the the tidal forces between individual stars will get their control and the galaxy changes into elliptical galaxy again. The pancake-like shape is therefore typical for galaxies of average-age with strong photon and neutrino flux from polar areas of central black hole.

The Sombrero galaxy therefore appears for me like the mixture (a product of collision) of two galaxies of very different age.

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.