NGC 3169

NGC 3169 is a spiral galaxy about 75 million light years away in the constellation Sextans. It has the morphological classification SA(s)a pec, which indicates this is a pure, unbarred spiral galaxy with tightly-wound arms and peculiar features. There is an asymmetrical spiral arm and an extended halo around the galaxy. It is a member of the NGC 3166 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.

This is a LINER 2 galaxy that displays an extended emission of X-rays in the region of the nucleus. A hard X-ray source at the center most likely indicates an active galactic nucleus. The stellar population in the nucleus, and a ring at an angular radius of 6″, shows an age of only one billion years and is generally younger than the surrounding stellar population. This suggests that a burst of star formation took place in the nucleus roughly one billion years ago.

NGC 3169 is located in close physical proximity to NGC 3166, and the two have an estimated separation of around 160 kly (50 kpc). Their interaction is creating a gravitational distortion that has left the disk of NGC 3166 warped. Combined with NGC 3156, the three galaxies form a small group within the larger Leo 1 group. The three are embedded within an extended ring of neutral hydrogen that is centered on NGC 3169.

Supernovae
In 1984, a Type II-L supernova was discovered in this galaxy. Designated 1984E, the spectrum of this event at maximum light showed prominent Balmer lines that indicated the explosion occurred inside a dense shell of hydrogen surrounding the star. This shell was likely created by a strong stellar wind from the progenitor star. A second supernova was discovered in 2003: SN 2003 cg (type Ia, mag. 14.4).