NGC 3166
NGC 3169 and 3166 ~ The Disturbed Galaxy Duo
Optics:   Ritchey–Chrétien 20" F/8.2 (4166mm FL) Processing:   PixInsight, Photoshop
Camera:   SBIG STXL-11000 with Adaptive Optics Date:   Dec 2017 to Jan 2018
11 Megapixel (4008 x 2672 16-bit sensor) Location:   Columbus, Texas
Exposure:   LRGB = 500:90:80:100 minutes Imager:   Kent E. Biggs
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.

NGC 3166 Old