This new image from NASA's Hubble
Space Telescope and its Wide Field Planetary Camera
2 (WFPC2) shows the unique galaxy pair called NGC
3314. Through an extraordinary chance alignment,
a face-on spiral galaxy lies precisely in front
of another larger spiral. This line-up provides
us with the rare chance to visualize dark material
within the front galaxy, seen only because it is
silhouetted against the object behind it.
Dust lying in the spiral arms of the
foreground galaxy stands out where it absorbs light
from the more distant galaxy. This silhouetting
shows us where the interstellar dust clouds are
located, and how much light they absorb. The outer
spiral arms of the front galaxy appear to change
from bright to dark, as they are projected first
against deep space, and then against the bright
background of the other galaxy.
NGC 3314 lies about 140 million light-years
from Earth, in the direction of the southern hemisphere
constellation Hydra. The bright blue stars forming
a pinwheel shape near the center of the front galaxy
have formed recently from interstellar gas and dust.
In many galaxies, interstellar dust
lies only in the same regions as recently formed
blue stars. However, in the foreground galaxy, NGC
3314a, there are numerous additional dark dust lanes
that are not associated with any bright young stars.
A small, red patch near the center
of the image is the bright nucleus of the background
galaxy, NGC 3314b. It is reddened for the same reason
the setting sun looks red. When light passes through
a volume containing small particles (molecules in
the Earth's atmosphere or interstellar dust particles
in galaxies), its color becomes redder.
The Hubble Heritage color image of
NGC 3314 was constructed from archival images taken
with WFPC2 in April 1999 by Drs. William Keel and
Ray White III (University of Alabama) in blue and
infrared light, combined with new images obtained
by the Heritage team in March 2000 using blue, green
and red filters.
Credit: NASA and The Hubble
Heritage Team (STScI/AURA)
Acknowledgments: William Keel (U. Alabama)