Better known as M106, bright
NGC 4258 is about 30 thousand light years across and
21 million light years away
toward the northern constellation
The yellow and red hues in
image show the
as seen in visible and
(blue and purple) reveal two extra
spiral arms -- arms that don't align with the more familiar tracers
of stars, gas, and dust.
an analysis of
and radio data suggests
that the anamolous arms are composed of material
heated by shock waves.
Detected at radio wavelengths,
powerful jets originating in the
galaxy's core likely drive the shocks into the disk
of NGC 4258.