NGC 3356 in Leo

February 2022 - Galaxy of the Month

NGC 3356 is part of a small group of galaxies in Leo. NGC 3356 itself is classified as an Sb disturbed spiral. It was first discovered by William Herschel in 1784. NGC 3356 is also known as VV 529 from Vorontsov-Velyaminov’s catalogue of interacting galaxies.

The next galaxy in the field, NGC 3349, was found by Marth in 1865. It is also an interacting system and has the designation VV 514. This object is actually a pair of galaxies, although I think Marth only saw a single galaxy here.

There is also third galaxy, NGC 3362, close by in the same field, which is another Marth discovery. Marth was using Lassell’s 48” speculum metal telescope from Malta for these discoveries.

NGC 3356 is obviously distorted and NASA/IPAC Extragalactic Database (NED) suggests that the distorting galaxy maybe UGC 5857. NGC 3356 is thought to be at a distance of around 85 Mpc, although the distance estimates vary quite a lot. Deep images show a lot of star forming regions in its spiral arms and it is very blue.

NGC 3349 is also a very blue spiral galaxy. It has a companion listed as PGC 2800964 which is probably both a real as well as an apparent companion. PGC 2800964 is heavily distorted and lies at about the same distance as NGC 3349 (approximately 375 million light-years). NGC 3349 is also a radio galaxy. It is also possibly a WR type galaxy which suggests a lot of recent star formation. WR or Wolf-Rayet galaxies show the spectra of Wolf-Rayet stars which suggests the presence of a lot of them, which implies a lot of recent star formation to make these massive stars.

NGC 3362 is another very blue face on spiral. It is classified as Seyfert 2 and is also a radio source. It has a fairly wide spiral structure delimited by many star forming regions and star clusters. It is not physically associated with the other galaxies, being at quite a different distance.

Perhaps unsurprisngly none of the galaxies mentioned here make it into the Night Sky Observer's Guide (NSOG) or other observing guides. As Herschel found NGC 3356 it should not be that difficult in medium sized telescopes. Marth’s objects tend to be unspectacular so it is likely that a telescope of 40cm+ will be needed to see NGC 3349 and NGC 3362 on a good night. I would be interested to know what aperture Is required to see the second galaxy in the NGC 3349 pair. The whole group fits in the field of view of a modern hyperwide eyepiece at, say 265x. I suspect that to split the two galaxies in the NGC 3349 pair will require higher power and a dark transparent sky.

Owen Brazell - Galaxy Section Director