GALEX Poster
From sparkling blue rings to dazzling golden disks, Galaxy Evolution
Explorer (Galex) scientists are handing out a collection of their finest
galactic treasures at the January 2006 American Astronomical Society
meeting in Washington, D.C.
Mined from the mission's Survey of Nearby Galaxies data, these cosmic gems
were collected with the telescope's sensitive ultraviolet instruments. The
gallery of galaxies has been made into a poster for meeting attendees
visiting the mission's booth. Organized from far-ultraviolet to
near-ultraviolet bright galaxies, this poster encapsulates the heart of
the mission to study how galaxies and star formation rates have changed
over the past 10 billion years.
Events in space take millions or billions of years to unfold, which means
that astronomers can't watch individual galaxies and stars age over time.
Luckily, because the physics of light travel dictates that the farther
away an object is from Earth, the longer it takes for its light to travel
to us, the universe can be thought of as a time machine. By building
telescopes sensitive enough to capture objects that are 10 billion
light-years away, astronomers can essentially see an object the way it
looked 10 billion years ago. Galex astronomers are using this phenomenon
to their advantage by taking snapshots of different galaxies at various
distances in space. By comparing portraits of numerous objects at various
times in the universe's history, the team can begin to piece together the
life cycle of stars and galaxies.
For the poster, Galex scientists organized 196 different nearby galaxies
in bins of increasing ultraviolet color. By placing the various snapshots
side by side, astronomers can see how galaxies age differently. When
viewed in ultraviolet, active star-forming regions in galaxies can be
seen as glittering blue structures, while a soft, golden glow indicates
the presence of older stars.
The 196 galaxies represented in the poster were selected from more than
1,000 galaxies in the "Ultraviolet Atlas of Nearby Galaxies." So far, the
Galex mission has surveyed more than 100 million galaxies.
