July 26, 2013
WIYN Focuses On Whirlpool Galaxy
Brett Smith for redOrbit.com - Your Universe Online
Astronomers have been observing the Whirlpool Galaxy since the 18th century, but they've never seen it like this.
A new One Degree Imager (ODI) camera at the Kitt Peak National Observatory in Arizona has captured stunning new images of the distant spiral galaxy in never-before-seen detail. When used with the WIYN 3.5-meter telescope at the observatory, the camera is able to provide images of the Whirlpool Galaxy and its companion galaxy in one pointing - something even the Hubble Telescope is incapable of doing.
Katherine Rhode, an astronomer at the University of Indiana, led the team that captured these new images as part of a project to survey spiral and elliptical galaxies and learn how these giant galaxies form and evolve.
"The WIYN telescope is an ideal telescope for the survey because of its wide field and because it produces some of the sharpest, highest-quality images possible with a ground-based telescope," Rhode said. "WIYN's 3.5-meter mirror is also very efficient at gathering light from astronomical objects, so it allows us to image faint objects, like individual star clusters within the galaxies."
A major problem with ground-based telescopes is known as "seeing," or the twinkling of stars. Caused by air movements in the Earth's atmosphere, these visual disturbances are minimized at certain sites, like high altitudes in a dry climate.
"The WIYN telescope on Kitt Peak is known for producing excellent, steady images with high resolution, or sharpness," said Eric Hooper, interim director at WIYN, a partnership among the University of Wisconsin-Madison (W), Indiana University (I), Yale University (Y), and the National Optical Astronomy Observatories (N).
During the WIYN team's survey, the ODI camera spent approximately one hour observing the Whirlpool Galaxy, or M51, through blue, green, and red filters. The images taken through these filters were later combined to create a "true-color" image - with redder, cooler objects emitting light at longer wavelengths and hotter, bluer objects emitting shorter light wavelengths.
Despite the galaxy's distance of 30 million light years from Earth, the camera's image clearly depicts clusters of young, hot stars in the spiral arms. The images also show dark "dust lanes" comprised of sooty material left by previous stars.
A bridge of luminous stars and gas that connects Messier 51 to its companion galaxy, NGC 5195, can also be seen containing some of these dust lanes. NGC 5195 is considered a peculiar galaxy with an unusual morphology. Scientists attributed its unclassifiable shape to gravitational forces from the Whirlpool Galaxy.
The Whirlpool Galaxy was first discovered in 1773 by French astronomer Charles Messier, who listed the faint, fuzzy object as '51' in his catalog. In 1845, William Parsons, the 3rd Earl of Rosse, used a 72-inch telescope to observe the galaxy.
The galaxy is widely observed by astronomers, being the one-time target of almost every telescope in the northern hemisphere. In 2005, astronomers caught a supernova near the base of one of its spiral arms. In 2011, astronomers caught another supernova thought to be caused by a yellow supergiant star around 20 times the size of our sun.