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Hubble Celebrates the International Year of
Astronomy with the Galaxy Triplet Arp 274
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Name: Arp 274, NGC 5679
Description: Triple galaxy system
Position (J2000): R.A. 14h 35m 8s.83 Dec. +05° 21' 30".80
Constellation: Virgo
Distance: 400 million light-years or 120 megaparsecs
Dimensions: The image is nearly 2 arcminutes (216,000 light-years) wide.
Exposure Date(s): April 1/2, 2009
Image Credit: NASA, ESA, M. Livio and the Hubble Heritage Team
Release Date: April 3, 2009
Click the image to buy a print


On April 1-2, the Hubble Space Telescope photographed the winning target in the Space Telescope Science Institute's "You Decide" competition in celebration of the International Year of Astronomy (IYA).

The winner is a group of galaxies called Arp 274. The striking object received 67,021 votes out of the nearly 140,000 votes cast for the six candidate targets.

Arp 274, also known as NGC 5679, is a system of three galaxies that appear to be partially overlapping in the image, although they may be at somewhat different distances. The spiral shapes of two of these galaxies appear mostly intact. The third galaxy (to the far left) is more compact, but shows evidence of star formation.

Two of the three galaxies are forming new stars at a high rate. This is evident in the bright blue knots of star formation that are strung along the arms of the galaxy on the right and along the small galaxy on the left.

The largest component is located in the middle of the three. It appears as a spiral galaxy, which may be barred. The entire system resides at about 400 million light-years away from Earth in the constellation Virgo.

Hubble's Wide Field Planetary Camera 2 was used to image Arp 274. Blue, visible, and infrared filters were combined with a filter that isolates hydrogen emission. The colors in this image reflect the intrinsic color of the different stellar populations that make up the galaxies. Yellowish older stars can be seen in the central bulge of each galaxy. A bright central cluster of stars pinpoint each nucleus. Younger blue stars trace the spiral arms, along with pinkish nebulae that are illuminated by new star formation. Interstellar dust is silhouetted against the starry population. A pair of foreground stars inside our own Milky Way are at far right.

The image is a composite of separate exposures made by the WFPC2 instrument on the Hubble Space Telescope. Three filters were used to sample broad wavelength ranges. One filter was used to sample narrowband emission. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:

   F673N (redshifted H-alpha): Red          F814W (I): Red          F606W (V): Green          F450W (B): Blue