New Image Shows Rich Neighborhood of Nearby Galaxy
10 January 2002
A new color image of the nearby irregular galaxy NGC 6822 shows a myriad of hot blue massive stars and several famous nebulae in impressive detail.
NGC 6822 is located approximately 1.6 million light-years from Earth, in the constellation Sagittarius. A member of the Milky Way galaxy's Local Group, it was discovered by E.E. Barnard in the early 1880s. Edwin P. Hubble conducted the first detailed investigation of the galaxy in 1925, using the new 100-inch telescope on Mount Wilson. An analysis of these plates by then-graduate student Susan E. Kayser in 1966 has remained the most complete study of this galaxy until now.
New images of NGC 6822 in eight filters were taken using the National Science Foundation's Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory (CTIO) near La Serena, Chile, by CTIO staff members Knut Olsen and Chris Smith.
The images were obtained as part of the NOAO Local Group Galaxies Survey, one of 13 active survey projects fostered by the National Optical Astronomy Observatory.
Led by Principal Investigator Phil Massey of Lowell Observatory, Flagstaff, AZ, the goal of this survey is to obtain comprehensive imaging of all nearby galaxies in which active star formation is occurring, enabling studies of the galaxies' stellar populations and their gas content. Follow-up spectroscopic studies are planned using the Gemini North and Gemini South telescopes, the WIYN telescope, and the Multiple Mirror Telescope.
The 199th meeting of the American Astronomical Society (AAS) in Washington, DC, marks the first public release of data from the survey. The images have been processed at Lowell Observatory, a process that takes many months. This special color rendition of NGC 6822 was made by Travis Rector of the National Radio Astronomy Observatory.
Shay Holmes, an undergraduate at the College of Charleston, SC, presents a poster paper at the AAS meeting today on the number of Hydrogen-II regions in NGC 6822, which have been observed by the survey with greater area coverage and considerably greater sensitivity than any previous efforts.
Other members of the Local Group survey team include Paul Hodge (University of Washington), George Jacoby (WIYN), Nichole King (STScI), and Abi Saha (Kitt Peak National Observatory/NOAO).
Detailed images of the nebulae at the top center edge of the galaxy, known as Hubble-X and Hubble-V, were released by the Space Telescope Science Institute's Hubble Heritage Project on January 4, 2001, and December 6, 2001, respectively.
CTIO is part of NOAO, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the National Science Foundation.
NOAO Public Information Officer