HUBBLE MOSAIC OF THE MAJESTIC SOMBRERO GALAXY
NASA's Hubble Space Telescope has trained its razor-sharp
eye on one of the universe's most stately and photogenic
galaxies, the Sombrero galaxy, Messier 104 (M104).
The galaxy's hallmark is a brilliant white, bulbous
core encircled by the thick dust lanes comprising
the spiral structure of the galaxy. As seen from
Earth, the galaxy is tilted nearly edge-on. We view
it from just six degrees north of its equatorial
plane. This brilliant galaxy was named the Sombrero
because of its resemblance to the broad rim and
high-topped Mexican hat.
At a relatively bright magnitude of +8, M104 is
easily seen through small telescopes. The Sombrero
lies at the southern edge of the rich Virgo cluster
of galaxies and is one of the most massive objects
in that group, equivalent to 800 billion suns. The
galaxy is 50,000 light-years across and is located
28 million light-years from Earth.
Hubble easily resolves M104's rich system of globular
clusters, estimated to be nearly 2,000 in number
-- 10 times as many as orbit our Milky Way galaxy.
The ages of the clusters are similar to the clusters
in the Milky Way, ranging from 10-13 billion years
old. Embedded in the bright core of M104 is a smaller
disk, which is tilted relative to the large disk.
X-ray emission suggests that there is material falling
into the compact core, where a 1-billion-solar-mass
black hole resides.
In the 19th century, some astronomers speculated
that M104 was simply an edge-on disk of luminous
gas surrounding a young star, which is prototypical
of the genesis of our solar system. But in 1912,
astronomer V. M. Slipher discovered that the hat-like
object appeared to be rushing away from us at 700
miles per second. This enormous velocity offered
some of the earliest clues that the Sombrero was
really another galaxy, and that the universe was
expanding in all directions.
The Hubble Heritage Team took these observations
in May-June 2003 with the space telescope's Advanced
Camera for Surveys. Images were taken in three filters
(red, green, and blue) to yield a natural-color
image. The team took six pictures of the galaxy
and then stitched them together to create the final
composite image. One of the largest Hubble mosaics
ever assembled, this magnificent galaxy has an angular
diameter of nearly one-fifth the diameter of the
Credit: NASA and The Hubble Heritage Team