Thursday, June 2, 2011

Astronomers Unveil Most Complete 3-D Map of Local Universe

Astronomers unveiled the most complete 3-D map of the local universe (out to a distance of 380 million light-years) ever created. Taking more than 10 years to complete, the 2MASS Redshift Survey (2MRS) also is notable for extending closer to the Galactic plane than previous surveys - a region that's generally obscured by dust.

The 2MASS Redshift Survey (2MRS) is based on 2D images of galaxies generated by the earlier Two-Micron All-SkySurvey (2MASS). The 2MASS Redshift Survey survey gives preceding maps a third dimension by accounting for redshift, or light that's shifted to longer wavelengths -- or the red part of the light spectrum -- as it comes in from distant galaxies. The further away a galaxy is, the greater its redshift.

2MRS chose galaxies to map from images made by the Two-Micron All-SkySurvey (2MASS). This survey scanned the entire sky in three near-infrared wavelength bands. Near-infrared light penetrates intervening dust better than visible light, allowing astronomers to see more of the sky. But without adding redshifts, 2MASS makes only a 2-D image. Some of the galaxies mapped had previously-measured redshifts, and Huchra started painstakingly measuring redshifts for the others in the late 1990s using mainly two telescopes: one at the Fred Lawrence Whipple Observatory on Mt. Hopkins, AZ, and one at the Cerro Tololo Inter-American Observatory in Chile. The last observations were completed by 2MRS observers on these telescopes shortly after Huchra's death in October 2010.

Source: CfA Harvard 

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