| NGC 1672 | |
| Epoch: | J2000 |
| Type: | (R')SB(r)bc |
| Ra: | [1] |
| Dist Ly: | [2] |
| Z: | 1331 ± 3 km/s |
| Appmag V: | 10.3 |
| Size V: | 6.6 × 5.5 |
| Constellation Name: | Dorado |
| Names: | PGC 15941 |
NGC 1672 is a barred spiral galaxy located in the constellation Dorado. It was discovered by the astronomer James Dunlop on November 5, 1826.[3] It was originally unclear whether it was a member of the Dorado Group, with some sources[4] finding it to be a member and other sources[5] rejecting its membership. However, recent tip of the red-giant branch (TRGB) measurements indicate that NGC 1672 is located at the same distance as other members, suggesting it is indeed a member of the Dorado Group.[2]
NGC 1672 has a large bar which is estimated to measure around 20 kpc.[6] It has very strong radio emissions emanating from its nucleus, bar, and the inner portion of the spiral arm region. The nucleus is Seyfert type II and is engulfed by a starburst region. The strongest polarized emissions come from the northeastern region which is upstream from its dust lanes. Magnetic field lines are at large angles with respect to the bar and turn smoothly to the center.
Two supernovae have been observed in NGC 1672: SN 2017gax (type Ib/c, mag. 14.1)[7] and SN 2022aau (type II, mag. 16.3).[8]
The center of the galaxy contains a high surface brightness bar, and four filament-like spiral arms extend outward from the ends of this bar. The spiral arms are asymmetric; one of the arms in the northeast part of the disk is significantly brighter than its counterpart on the other side. The spiral arms also contain numerous star formation regions, some of which may be as large as .[9]
The classification of the nucleus of NGC 1672 is uncertain. Most galaxies may be classified by their spectra as having one of three different types of nuclei:[10]
NGC 1672, however, is one of several nearby galaxies that does not fit into this classification scheme, as its spectrum appears intermediary between these three classes of objects.[10] It may in fact contain both nuclear star formation regions and an AGN. In some wave bands (such as in ultraviolet light), the star formation regions are the primary source of emission.[11]