NASA’s Galaxy Evolution Explorer Mission Captures Galaxies

The most sensitive and comprehensive ultraviolet image ever taken of
the Andromeda Galaxy, our nearest large neighbor galaxy, has been
captured by NASA’s Galaxy Evolution Explorer. The image is one of
several being released to the public as part of the mission’s first
collection of pictures.

“The Andromeda image gives us a snapshot of the most recent star
formation episode,” said Dr. Christopher Martin, Galaxy Evolution
Explorer principal investigator and an astrophysics professor at the
California Institute of Technology in Pasadena, which leads the
mission. “By studying this view of the galaxy in the process of
forming stars, we can better understand how that fundamental process
works, such as where stars form, how fast and why.”

The image of Andromeda, the most distant object the naked eye can see,
is a mosaic of nine images taken in September and October of 2003. It
combines two ultraviolet colors, one near ultraviolet (red) and one
far ultraviolet (blue).

For comparison, a second image shows the Andromeda Galaxy, also called
Messier 31, in visible light. Both images, along with other new
pictures from the Galaxy Evolution Explorer, are available online at

http://www.galex.caltech.edu/ and

http://photojournal.jpl.nasa.gov/mission/GALEX .

The new collection of
images also includes views of several nearby galaxies; Stephan’s
Quintet of Galaxies; an all-sky survey image of the globular star
cluster M2; and a deep image of the sky in the constellation Bootes.
The Galaxy Evolution Explorer team is also releasing the first batch
of scientific data, so the science community can propose additional
observations for the mission. These images and data display the power
of the Galaxy Evolution Explorer to collect sensitive ultraviolet
images of large parts of the sky.

“It’s very rewarding and exciting for the team to see the fruits of
their labors,” said Kerry Erickson, the mission’s project manager at
NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Because people are
accustomed to seeing objects in visible light, it’s amazing to see how
different the universe looks in ultraviolet and how much information
is revealed to us by those observations.”

Scientists are interested in learning more about the Andromeda galaxy,
including its brightness, mass, age, and the distribution of young
star clusters in its spiral arms. This will provide a tremendous
amount of information about the mechanisms of star formation in
galaxies, and will help them interpret ultraviolet and infrared
observations of other, more distant galaxies.

The Galaxy Evolution Explorer launched on April 28, 2003. Its goal is
to map the celestial sky in the ultraviolet and determine the history
of star formation in the universe over the last 10 billion years. From
its orbit high above Earth, the spacecraft will sweep the skies for up
to 28 months using state-of-the-art ultraviolet detectors. Looking in
the ultraviolet singles out galaxies dominated by young, hot,
short-lived stars that give off a great deal energy at that
wavelength. These galaxies are actively creating stars, and therefore
provide a window into the history and causes of galactic star
formation.

In addition to leading the mission, Caltech is also responsible for
science operations and data analysis. JPL, a division of Caltech,
manages the mission and led the science instrument development. The
mission is part of NASA’s Explorers Program, managed by the Goddard
Space Flight Center, Greenbelt, Md. The mission’s international
partners are France and South Korea. Caltech manages JPL for NASA.