Galaxy Evolution Explorer Celebrates Five Years in Space

Feature April 28, 2008


Galaxy Evolution Explorer Celebrates Five Years in Space



Since its launch five years ago, the Galaxy Evolution Explorer has photographed
hundreds of millions of galaxies in ultraviolet light. M106 is one of those
galaxies, and from 22 light years away, it strikes a pose in blue and gold for this
new commemorative portrait.

The galaxy's extended arms are the blue filaments that curve around its edge,
creating its outer disk. Tints of blue in M106's arms reveal hot, young massive
stars. Traces of gold toward the center show an older stellar population and
indicate the presence of obscuring dust.

"We see these arms in optical-light images, but they are very faint and diffuse.
These structures really pop out in the ultraviolet due to the exquisite sensitivity of
the detectors on the Galaxy Evolution Explorer," said Mark Seibert of the
Carnegie Institution of Washington in Pasadena, Calif.

From 24 million light-years away, neighboring galaxy NGC 4248 also makes a
memorable appearance, sitting just right of M106. The irregular galaxy looks like
a yellow smudge, with a bluish-white bar in the center. The galaxy's outer golden
glow indicates a population of older stars, while the blue central region shows a
younger stellar demographic.

Dwarf galaxy UGC 7365 emerges at the bottom center of this image, as a faint
yellow smudge directly below M106. This galaxy is not forming any new stars,
and looks much smaller than M106 despite being closer to Earth, at 14 million
light-years away.

Over the past five years, the Galaxy Evolution Explorer has imaged half a billion
objects over 27,000 square degrees of sky -- equivalent to an area that would be
covered by 138,000 full moons. The telescope orbits Earth every 94 minutes and
travels approximately 408,470 million miles per day. Its overarching question is:
how do galaxies grow and change over 10 billion years of cosmic history?

"Frankly we have only begun to scratch the surface of this vast data set.
Astronomers will be mining the telescope's data archive for the next decade," said
Chris Martin, of the California Institute of Technology, Pasadena, Calif. He is
principal investigator for the Galaxy Evolution Explorer mission, which is
managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.

M106, also known as NGC 4258, is located in the constellation Canes Venatici.
This image is a two-color composite, where far-ultraviolet light is blue, and near-
ultraviolet light is red.

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