NASA Spitzer Telescope Spies Parallelogram-Shaped Galactic Meal
Peering into the “gut” of the galaxy Centaurus A, NASA’s Spitzer Space
Telescope has captured in unprecedented detail this massive galaxy’s
last big meal: a spiral galaxy twisted into a parallelogram-shaped
structure of dust.
The findings were presented today at the American Astronomical Society
annual meeting in Denver, Colo. A stunning image of the galaxy and its
bizarre dust structure can be found at
http://www.spitzer.caltech.edu/Media/releases/ssc2004-09/index.shtml .
While previous observations with other telescopes have revealed this
galactic remnant, it appeared as one long and irregular bar of dust.
Spitzer’s uniquely sensitive infrared eyes allowed the telescope to
see clearly this strangely geometric structure for the first time.
“Now we can actually see the shape of this structure, which helps us
explain how it arose,” said Dr. Jocelyn Keene, principal investigator
for the new research and an astronomer at NASA’s Jet Propulsion
Laboratory and the California Institute of Technology, both in
Pasadena, Calif.
Located 10 million light-years away, Centaurus A is a type of galaxy
known as “elliptical.” It is one of the brightest sources of radio
waves in the sky, which suggests the presence of a supermassive black
hole at its center. About 200 million years ago, this galaxy is
believed to have consumed a smaller spiral galaxy – the contents of
which appear to be churning inside Centaurus A’s core, triggering new
generations of star birth.
Resolving this unusual parallelogram structure has helped astronomers
finally put together a picture of its history. The geometric shape can
be explained using a model that describes a flat spiral galaxy falling
into an elliptical galaxy and becoming twisted and warped in the
process. The folds in the warped disc, when viewed nearly edge on,
take on the appearance of a parallelogram. The model predicts that the
leftover galaxy will ultimately flatten into a plane before being
entirely devoured by Centaurus A. Warped discs like this are the
“smoking guns” of galactic cannibalism, providing proof that one
galaxy once made a meal of another.
Such galactic feeding has long thought to be a mechanism by which
giant elliptical galaxies form and grow, and likely provides the fuel
that drives the strong radio activity surrounding Centaurus A’s
central black hole.
Other authors of this research include Dr. Alice Quillen of the
University of Rochester, N.Y., and Drs. Daniel Stern, Varoujan
Gorjian, Karl Stapelfeldt, Charles Lawrence, Peter Eisenhardt and
Michael Werner of JPL.
For more information about the Spitzer Space Telescope, visit
www.spitzer.caltech.edu&donottrack=true .
Launched on August 25, 2003, from Cape Canaveral, Fla., the Spitzer
Space Telescope is the fourth of NASA’s Great Observatories. This
program includes the Hubble Space Telescope, Chandra X-ray Observatory
and Compton Gamma Ray Observatory. JPL manages the Spitzer Space
Telescope mission for NASA’s Office of Space Science, Washington.
Science operations are conducted at the Spitzer Science Center. The
California Institute of Technology manages JPL.
