A tale of galactic collisions by europeanspaceagency on Flickr.

Via Flickr:
When we look into the distant cosmos, the great majority of the objects we see are galaxies: immense gatherings of stars, planets, gas, dust, and dark matter, showing up in all kind of shapes. This Hubble picture registers several, but the galaxy catalogued as 2MASX J05210136-2521450 stands out at a glance due to its interesting shape. This object is an ultraluminous infrared galaxy which emits a tremendous amount of light at infrared wavelengths. Scientists connect this to intense star formation activity, triggered by a collision between two interacting galaxies. The merging process has left its signs: 2MASX J05210136-2521450 presents a single, bright nucleus and a spectacular outer structure that consists of a one-sided extension of the inner arms, with a tidal tail heading in the opposite direction, formed from material ripped out from the merging galaxies by gravitational forces. The image is a combination of exposures taken by Hubbleâs Advanced Camera for Surveys, using near-infrared and visible light.

The image is a combination of exposures taken by Hubble’s Advanced Camera for Surveys, using near-infrared and visible light. A version of this image was submitted to the Hubble’s Hidden Treasures image processing competition by contestant Luca Limatola.

Credits: ESA/Hubble & NASA Acknowledgement: Luca Limatola

Artistic Rendering of BX442

Illustration Credit: Joe Bergeron (Dunlap Institute for Astronomy & Astrophysics) 

Explanation: This galaxy is so large, so fully-formed, astronomers say it shouldn’t exist at all. It’s called a “grand-design” spiral galaxy, but this one is older than most galaxies of its kind. According to a new study conducted by researchers using NASA’s Hubble Telescope, it dates back roughly 10.7-billion years — and that makes it the most ancient spiral galaxy we’ve ever discovered.

The hallmark of a grand design galaxy is its well-formed spiral arms, but getting into this conformation takes time. When astronomers look at most galaxies as they appeared billions and billions of years ago, they look clumpy and irregular. A 10.7-billion-year-old entity, BX442 came into existence a mere 3-billion years after the Big Bang. That’s not a lot of time on a cosmic time scale, and yet BX442 looks surprisingly put together. So much so, in fact, that astronomers didn’t believe it at first, chalking their unusual observation up to the accidental alignment of two separate galaxies. But further investigations, conducted at the W.M. Keck Observatory in Hawaii, revealed BX442 to be the real thing.

So how does a galaxy that shouldn’t exist come to be? The researchers think the answer may have something to do with a companion dwarf galaxy looming near BX442 (in the image up top, it’s the separate circular cluster in the upper right). Simulations conducted by University of Arizona researcher Charlotte Christenson indicate that gravitation interactions between the two, which she says appear to be in the process of colliding, may have helped BX442 take shape.

Source: Hubble has spotted an ancient galaxy that shouldn’t exist

Hubble Telescope’s Latest Deep Field Image

Like photographers assembling a portfolio of best shots, astronomers have assembled a new, improved portrait of mankind’s deepest-ever view of the universe.

Called the eXtreme Deep Field, or XDF, the photo was assembled by combining 10 years of NASA Hubble Space Telescope photographs taken of a patch of sky at the center of the original Hubble Ultra Deep Field. The XDF is a small fraction of the angular diameter of the full Moon.

(Click Link for Zoomable Version)

Hubble Telescope Helps Solve Galaxy-Evolution Mystery 

New observations from NASA’s Hubble Space Telescope have helped astronomers crack a longstanding puzzle about galaxy evolution.

For years, scientists have wondered why galaxies that have ceased forming new stars — so-called “quenched galaxies" — were smaller long ago than they are today. Perhaps, they thought, ancient quenched galaxies continued to grow by merging with smaller cousins that had also stopped producing stars.

But that hypothesis is off the mark, a new study reports.

"We found that a large number of the bigger galaxies instead switch off at later times, joining their smaller quenched siblings and giving the mistaken impression of individual galaxy growth over time,"co-author Simon Lilly, of the Swiss Federal Institute of Technology in Zurich, said in a statement.

The researchers used observations from Hubble’s Cosmic Evolution Survey (COSMOS), the Canada-France-Hawaii Telescope and the Subaru Telescope to map an area of the sky about nine times the size of the full moon. They used the observations to make a video of the quenched galaxies as seen by Hubble.

The team studied and tracked the quenched galaxies in this patch through the last eight billion years of the universe’s history, eventually determining that most of them did not grow over time but rather remained small and compact.  

So it appears that star production simply switched off earlier in older galaxies compared to younger ones. This makes sense, researchers said; star-forming galaxies were smaller in the early universe, after all, so they would hit growth and evolution milestones at a relatively smaller size.

"The apparent puffing up of quenched galaxies has been one of the biggest puzzles about galaxy evolution for many years,"said lead author Marcella Carollo, also of the Swiss Federal Institute of Technology in Zurich. “Our study offers a surprisingly simple and obvious explanation to this puzzle. Whenever we see simplicity in nature amidst apparent complexity, it’s very satisfying."

The Hubble Space Telescope, a collaboration between NASA and the European Space Agency, has made more than 1 million science observations since its launch in 1990, and it’s still going strong. NASA announced earlier this year that it had extended the telescope’s science operations through April 2016.

- See more at: http://www.space.com/22200-hubble-galaxy-evolution-mystery.html#sthash.Gs6Opo5b.dpuf

You Are Here: How Astronomical Surveys Are Pinpointing Our Place in the Cosmos

Illustration: A theoretical image rendering of what the milky way might look like (our technologies haven’t come close to traveling far out enough to snap gpoys of our home galaxy. via outerspaceuniverse)

Upcoming telescope projects on Earth and in space will map out billions of stars and galaxies all around us

Like surveyors charting out a parcel of land by measuring angles, distances and elevations, astronomers have long mapped the positions of celestial objects in the sky.

Those celestial maps are about to see some major revisions. New and upcoming campaigns using ground-based telescopes or spacecraft promise to fill in many new details in astronomers’ maps of the sky. Together these projects will catalogue detailed positional information on several billion stars and galaxies near and far.

One of the most dramatic upgrades to celestial cartography should come from the European Space Agency’s Gaia spacecraft, which is scheduled to launch next year. After taking up a position in deep space, well beyond the orbit of the moon, Gaia will map the positions and distances of roughly one billion stars. The mission is the successor to the Hipparcos satellite, which launched in 1989 and whose catalogue still finds wide use. But that satellite charted just 120,000 stars or so, and only a slight minority were pinpointed with top-level precision.

By mapping out so many stars, astronomers hope to improve their understanding of our home galaxy’s layout. “The main science goal is to address the issues of our Milky Way—the structure and the dynamics,” Prusti says. Buried as we are within the Milky Way, humankind has never had a glimpse of the galaxy in its entirety. The astronomer’s predicament is a bit like that of an artist who must sketch the Manhattan skyline from midtown, instead of from a clear vantage point across the Hudson River. Just as the artist can inspect Manhattan’s skyscrapers one by one to reconstruct the skyline in her sketch, the astronomer can fill in a map of the galaxy one star at a time.

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