M94: Beyond the Blue
Explanation:
Today's galaxy,
M94 (NGC 4736),
lies 15 million light-years away in the constellation
Canes
Venatici.
In the red light image (left), its very bright nucleus and
tightly wound spiral arms seem to slowly fade into a faint outer disk.
But
when viewed in
wavelengths shorter than blue light -
ultraviolet (UV) light
- its appearance dramatically changes.
While the red light image highlights the older, cooler stars
of M94,
the UV picture (right), from the
shuttle-borne Ultraviolet Imaging
Telescope, is dominated by clusters of massive, hot stars a
mere 10 million
years young.
These UV bright young star clusters are mostly arranged in a
stunning ring nearly 7,000 light-years wide
around the galactic nucleus.
What controls this star forming activity?
Exploring
wavelengths
beyond the blue, astronomers now have
evidence that star forming activity in galaxies
like M94 can be
orchestrated
by the symmetric structure
of the galaxies themselves
instead of the titanic galaxy-galaxy collisions suspected in
yesterday's case of the
Cartwheel galaxy.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
