This is NOT a flying saucer! Messier 104 is a spiral galaxy (type Sa-Sb) seen in a nearly edge-on configuration. The large and bright central bulge of the galaxy is encircled by a flattened spiral disk, which appears as a ring of dust and stars from our viewing angle.
Visible: DSS (left) and HST (right)
The visible-light images from DSS (above, left) and HST (above, right) clearly reveal the obscuring dust in the foreground edge of the galaxy disk. If you look closely at the DSS image, you should even be able to tell that the dust disk is warped. Such warps are often the result of a close gravitational encounter with another nearby galaxy. To see what effect an intergalactic encounter with another galaxy can have on a thin galaxy disk, see the remarkable image here.
HST (left) and Near-Infrared: 2MASS (center) and Mid-Infrared: Spitzer (right)
Now look at the near-infrared and mid-infrared images and compare them with the companion optical photo. See any difference? You will find that the obscuring dust is much less evident in the 2MASS and Spitzer pictures. This is good illustration of how infrared light can pierce through obscuring dust and why astronomers rely on infrared measurements to study star formation, which typically occurs in dusty interstellar environments. For an even more remarkable contrast of images, check out the optical and infrared views of the heavily obscured center (at optical wavelengths, anyway!) of our Milky Way Galaxy.
The far-infrared image was taken with the space-borne IRAS satellite in 1983. The photo clearly shows emission from Messier 104. Very little detail is evident, however, since the IRAS detectors were of relatively poor spatial resolution. Modern IR telescopes, such as the Spitzer Space Telescope have far better resolution and are be capable of producing much finer images of galaxies like M104.
Radio: NVSS (left) and X-Ray: ROSAT (right)
The images immediately above appear similar, but were taken by telescopes at opposite ends of the electromagnetic spectrum! The radio image (left) shows a central peak of bright emission (in red), but very little else. If the radio emission followed the visible-light distribution shown in the first images of this gallery (top of the page), we would expect to see the radio emission spread into a flattened ellipse. Since the radio emission is essentially point-like and is centrally located, we conclude that the source of the naturally-produced radio waves is the central bulge of M104, and not the extended disk.
Finally, the x-ray picture (above, right) also shows a central source of
emission. By coincidence, the false colors used in the x-ray image closely
resemble those used in the radio image. Unlike the radio map, however, two
additional sources of x-rays appear in the field of view. According to the
Extragalactic Database (NED), these secondary x-ray sources have been
as x-ray sources. Their exact nature cannot be determined until astronomers
measure their distances using
spectroscopy (the use of spectrum analysis).