The Two-Faced Whirlpool Galaxy

Article ID: 572381

Released: 12-Jan-2012 9:00 AM EST

Source Newsroom: Space Telescope Science Institute (STScI)

  • Credit: Stefan

    Hubble

  • Credit: NASA, ESA, M. Regan and B. Whitmore (STScI), R. Chandar (University of Toledo), S. Beckwith (STScI), and the Hubble Heritage Team (STScI/AURA)

    THE TWO-FACED WHIRLPOOL GALAXY These images by NASA's Hubble Space Telescope show off two different face-on views of the spiral galaxy M51, dubbed the Whirlpool Galaxy. The image at left, taken in visible light with the Advanced Camera for Surveys (ACS) in Jan. 2005, highlights the attributes of a typical spiral galaxy, including graceful, curving arms, pink star-forming regions, and brilliant blue strands of star clusters. In the image at right, most of the starlight has been removed, revealing the Whirlpool's skeletal dust structure, as seen in near-infrared light. This new image, that combines the Jan. 2005 ACS visible-light exposures with near-infrared-light exposures taken with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) in December 2005, is the sharpest view of the dense dust in M51. The narrow lanes of dust revealed by Hubble reflect the galaxy's moniker, the Whirlpool Galaxy, as if they were swirling toward the galaxy's core. These images will be presented on Jan. 13, 2011, at the American Astronomical Society meeting in Seattle, Wash.

EMBARGOED UNTIL: 3:45 pm (EST) January 13, 2011 These images by NASA's Hubble Space Telescope show off two dramatically different face-on views of the spiral galaxy M51, dubbed the Whirlpool Galaxy. The image at left, taken in visible light, highlights the attributes of a typical spiral galaxy, including graceful, curving arms, pink star-forming regions, and brilliant blue strands of star clusters. In the image at right, most of the starlight has been removed, revealing the Whirlpool's skeletal dust structure, as seen in near-infrared light. This new image is the sharpest view of the dense dust in M51. The narrow lanes of dust revealed by Hubble reflect the galaxy's moniker, the Whirlpool Galaxy, as if they were swirling toward the galaxy's core. To map the galaxy's dust structure, researchers collected the galaxy's starlight by combining images taken in visible and near-infrared light. The visible-light image captured only some of the light; the rest was obscured by dust. The near-infrared view, however, revealed more starlight because near-infrared light penetrates dust. The researchers then subtracted the total amount of starlight from both images to see the galaxy's dust structure. The red color in the near-infrared image traces the dust, which is punctuated by hundreds of tiny clumps of stars, each about 65 light-years wide. These stars have never been seen before. The star clusters cannot be seen in visible light because dense dust enshrouds them. The image reveals details as small as 35 light-years across. Astronomers expected to see large dust clouds, ranging from about 100 light-years to more than 300 light-years wide. Instead, most of the dust is tied up in smooth and diffuse dust lanes. An encounter with another galaxy may have prevented giant clouds from forming. Probing a galaxy's dust structure serves as an important diagnostic tool for astronomers, providing invaluable information on how the gas and dust collapse to form stars. Although Hubble is providing incisive views of the internal structure of galaxies such as M51, the planned James Webb Space Telescope (JWST) is expected to produce even crisper images. Researchers constructed the image by combining visible-light exposures from Jan. 18 to 22, 2005, with the Advanced Camera for Surveys (ACS) and near-infrared-light pictures taken in December 2005 with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Credit for the NICMOS image: NASA, ESA, M. Regan and B. Whitmore (STScI), and R. Chandar (University of Toledo) Credit for the ACS image: NASA, ESA, S. Beckwith (STScI), and the Hubble Heritage Team (STScI/AURA) Image files and more information about M51 are available on: http://hubblesite.org/news/2011/03 http://www.nasa.gov/hubble For additional information, contact: Ray Villard/Donna Weaver Space Telescope Science Institute, Baltimore, Md. 410-338-4514/410-338-4493 villard@stsci.edu / dweaver@stsci.edu Michael Regan Space Telescope Science Institute, Baltimore, Md. 410-338-4769 mregan@stsci.edu The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.


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