This pair of galaxies
is definitely disturbed. They lie in the direction of Sextans,
a constellation named for the astronomical instrument invented
by Johannes Hevelius in 1687. The larger of the two galaxies
(lower right) is NGC 3169. Prior to being "disturbed", it was and still is a spiral galaxy
with clearly defined spiral arms, however the arms are being
pulled on by the nearby galaxy NGC 3166 (upper left). This
gravitational tug-of-war has affected both galaxies
substantially, hence the unnofficial name
The Disturbed
Galaxy Duo. Looking closely at NGC 3169, you can see
fainter cloudy whitish material all around it; this material is actually
billions of stars so far away that they do not resolve into
points of light. NGC 3169 has probably encountered
a previous galaxy has already collided with it
and passed through it many times before finally being absorbed completely. All the faint cloudy areas
around NGC 3169 are actually millions of stars, many which likely have
planets orbiting them. The blue area
along the spiral arms indicate the formation of many new young
stars.
NGC 3166 (again upper left) is a barred spiral galaxy with a
small bright nucleus within which the short bright bar is
visible. It is less blue than NGC 3169, and therefore is not in
a phase of considerable star formation. At the far top
left is a third likely associated galaxy, NGC 3165, and at the
middle right what may look like a globular cluster is indeed far too
large and is actually a faint 16 magnitude eliptical galaxy PGC
29873. Both NGC 3165 and PGC 29873 appear relatively
undisturbed. All four galaxies are in the galactic group
Leo 1 Group and are embedded in an extend ring of neutral
hydrogen (not visible) centered on NGC 3169. The entire
group is between 60 and 75 million light years away from us.
Hovering over the top image reveals enlarged insets representing other
galaxies visible, most far mor distant! Note galaxy PGC 1253132 in the
upper left. It is likely the same size as our own Milky Way Galaxy, is
nearly a billion light years distant and appears to be
a type of ring galaxy. Click
here for
a full screen zoomable version of the image with annotations.
Below is the processing of this same image and data using the old
processing workflow. Hover over the below image to see a comparison of old
versus new workflows.
The stats on NGC 3169 are: RA 10h 14m 15s, Dec +03° 27' 58",
Mag: 10.3, Size 4.2'x2.9', and Class SA(s)a pec.