NGC 1672 is a barred spiral galaxy located in the constellation Dorado. It was discovered by the astronomer James Dunlop in November 5, 1826. It was originally unclear whether it was a member of the Dorado Group, with some sources finding it to be a member and other sources 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.
|Observation data (J2000 epoch)|
|Right ascension||04h 45m 42.500s|
|Declination||−59° 14′ 49.85″|
|Redshift||1331 ± 3 km/s|
|Distance||51.7 ± 3.0 Mly (15.86 ± 0.92 Mpc)|
|Apparent magnitude (V)||10.3|
|Apparent size (V)||6′.6 × 5′.5|
NGC 1672 has a large bar which is estimated to measure around 20 kpc. 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 2 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.
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 4′′.
- A nuclear HII region, a region which has a spectrum similar to that of star formation regions in the Milky Way and which therefore is associated with nuclear star formation activity.
- A Seyfert nucleus, a type of active galactic nucleus (AGN) that may contain a supermassive black hole.
- A low ionization nuclear emission-line region, a type of nuclear region with spectral line emission from weakly ionized gas that could contain either a star formation region or a supermassive black hole.
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. 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.
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- Seligman, Courtney. "New General Catalogue objects: NGC 1650 - 1699". cseligman.com. Retrieved 2021-04-29.
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- A. Sandage; J. Bedke (1994). Carnegie Atlas of Galaxies. Washington, D.C.: Carnegie Institution of Washington. ISBN 978-0-87279-667-6.
- P. Veron; A. C. Goncalves; M. P. Veron-Cetty (1997). "AGNs with composite spectra". Astronomy and Astrophysics. 319: 52–66. Bibcode:1997A&A...319...52V.
- A. L. Kinney; R. C. Bohlin; D. Calzetti; N. Panagia; et al. (1993). "An atlas of ultraviolet spectra of star-forming galaxies". Astrophysical Journal Supplement Series. 86: 5–93. Bibcode:1993ApJS...86....5K. doi:10.1086/191771.
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