Monday, 11 August 2008

The Galaxy Zoo

Dear Galaxy Zoo users,

Thanks for making Galaxy Zoo such a success!

With your help, we've been able to collect millions of classifications, with which to do science faster than we ever thought possible. We are currently preparing the first science papers for submission to peer-reviewed journals and we will keep you posted on the progress of the papers on the BLOG and the FORUM. From now on, if you classify galaxies on the ANALYSIS page, your classifications will continue to be recorded and will be part of the public release, but it won't be part of the first round of papers. Don't be alarmed if the galaxies are odd, this is part of the process of checking our results.

But we still need you! As part of our follow-up work, we need volunteers to review our set of possible merging galaxies. If you're already familiar with basic Galaxy Zoo analysis, click here to read the instructions and click here to take part. Galaxy Zoo 2 will go live in the near future featuring a much more detailed classification system, while further off we plan GalaxyZoo 3 with lots of exciting new data. We'll notify all of you via the newsletter when we're able to start these two new endeavours.

From AssociatedContent :
Hanny Van Arkel is not an astrophysicist or an astronomer. She does not even own a telescope. But that did not stop the 25-year-old school teacher living in Harleen in the Netherlands from making a startling astronomical discovery, thanks to a website called Galaxy Zoo.

Hanny Van Arkel was pouring over photographs of galaxies on the Galaxy Zoo Internet site when she noticed a bright, gaseous mass with a hole in the center. Hannah Van Arkel duly posted a query about the object on the Galaxy Zoo web site.

Galaxy Zoo is the brainchild of Yale University's Kevin Schawinski and Oxford's Chris Lintott. The idea was the post a millions images of the night sky taken by the Sloan Digital Sky Survey telescope in New Mexico and to ask the public to help classify the galaxies thus imaged; elliptical, spiral, or other. The human eye is much more sensitive than a computer at discerning patterns such as those of galaxies. Galaxy Zoo has garnered the help of hundreds of thousands of amateur astronomers eager to help in the classification effort.

Hanny Van Arkel's discovery, now called Hanny's Voorwerp or "Hanny's Object" is thought to be a circle of hot gas with a hole in the middle about 16,000 light years across and illuminated by a nearby quasar. Various Earth bound telescopes are attempting to image the object and the Hubble space telescope is scheduled to turn its mirror on Hanny's Voorwerp next year.

Anyone can log on to Galaxy Zoo and help in classifying galaxies imaged by the Sloan Digital Sky Survey telescope. There is a tutorial that helps the amateur astronomy distinguish between a spiral galaxy and an elliptical galaxy. A spiral galaxy has a central bulge and spiral arms, much like our own Milky Way Galaxy. An elliptical galaxy has only the bulge with no disk or spiral arms.

And news about our own galaxy, the Milky Way, from NASA :
Now, new images from NASA's Spitzer Space Telescope are shedding light on the true structure of the Milky Way, revealing that it has just two major arms of stars instead of the four it was previously thought to possess.
Since the 1950s, astronomers have produced maps of the Milky Way. The early models were based on radio observations of gas in the galaxy, and suggested a spiral structure with four major star-forming arms, called Norma, Scutum-Centaurus, Sagittarius and Perseus. In addition to arms, there are bands of gas and dust in the central part of the galaxy. Our sun lies near a small, partial arm called the Orion Arm, or Orion Spur, located between the Sagittarius and Perseus arms.

"For years, people created maps of the whole galaxy based on studying just one section of it, or using only one method," said Benjamin. "Unfortunately, when the models from various groups were compared, they didn't always agree. It's a bit like studying an elephant blind-folded."

Large infrared sky surveys in the 1990s led to some major revisions of these models, including the discovery of a large bar of stars in the middle of the Milky Way. Infrared light can penetrate through dust, so telescopes designed to pick up infrared light get better views of our dusty and crowded galactic center. In 2005, Benjamin and his colleagues used Spitzer's infrared detectors to obtain detailed information about our galaxy's bar, and found that it extends farther out from the center of the galaxy than previously thought.
The findings make the case that the Milky Way has two major spiral arms, a common structure for galaxies with bars. These major arms, the Scutum-Centaurus and Perseus arms, have the greatest densities of both young, bright stars, and older, so-called red-giant stars. The two minor arms, Sagittarius and Norma, are filled with gas and pockets of young stars. Benjamin said the two major arms seem to connect up nicely with the near and far ends of the galaxy's central bar.

"Now, we can fit the arms together with the bar, like pieces of a puzzle," said Benjamin, "and, we can map the structure, position and width of these arms for the first time." Previous infrared observations found hints of a two-armed Milky Way, but those results were unclear because the position and width of the arms were unknown.
In other words, "mostly armless", like the Venus de Milo.

1 comment:

Anonymous said...

Fascinating. Thanks for that story Zoƫ.