NGC 6744 -- A Sibling of the Milky Way
This image of spiral galaxy NGC 6744 from NASA's Wide-field Infrared Survey Explorer (WISE) is a mosaic of frames covering an area three full moons tall and three full moons wide (1.56 by 1.56 degrees). It is located in a constellation in the southern sky, Pavo, which is Latin for peacock.
There are relatively few large spiral galaxies in the local universe (within about 40 million light-years of our Local Group of galaxies). NGC 6744 is about 30 million light-years away and, compared to other local galaxies, is very similar to our Milky Way galaxy. In fact, if there are observers somewhere in this sibling galaxy looking back at the Milky Way, they might see a very similar image.
The galaxy's disk is about 175,000 light-years across, which is larger than the Milky Way's disk, making NGC 6744 kind of like the Milky Way's big brother. It has an elongated, or barred, core and distinct spiral arms. The spiral arms of the disk are the sites of star formation within the galaxy and are very dusty. Dust and star formation go together hand-in-hand. Dust in star-forming regions is relatively warm (temperatures of hundreds of Kelvins) and shows up as green and red in this infrared image from WISE. Throughout the disk and core are many, many older generations of stars whose temperatures are in the thousands of Kelvins. These stars are color-coded blue and cyan in this image.
This image was made from observations by all four infrared detectors aboard WISE. Blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is primarily light from stars. Green and red represent light at 12 and 22 microns, which is primarily emission from warm dust.
WISE is an all-sky survey, snapping pictures of the whole sky, including everything from asteroids to stars to powerful, distant galaxies.
JPL manages WISE for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.
More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.