NGC 1532
An edge-on barred spiral galaxy interacting with a dwarf companion.
NGC 1532, called Haley's Coronet, is a barred spiral galaxy seen edge-on, about 58 million light-years away in the constellation Eridanus. James Dunlop found it on 29 October 1826.
Its bulge has a boxy shape, which reveals that the bulge is actually a bar. In face-on galaxies, bars are easy to spot by eye, but in tilted galaxies like this one, careful study is needed to tell bulges and bars apart.
The galaxy likely has several small dwarf companions. It is clearly pulling on one of them, the shapeless dwarf galaxy NGC 1531. Tidal forces from that interaction have created unusual plumes rising above NGC 1532's disk. NGC 1532 is also a distant member of the Fornax Cluster.
Three supernovae have been seen in NGC 1532. SN 1981A, a Type II reaching magnitude 13.5, was found by Robert Evans on 24 February 1981. SN 2016iae, a Type Ic at magnitude 17.32, was discovered by ATLAS on 7 November 2016. SN 2016ija, a Type II at magnitude 16.5, was found by the Distance Less Than 40 Mpc Survey (DLT40) on 22 November 2016.
Quick Facts
- Epoch
- J2000
- Dec
- -32 · 52 · 26.745
- Ra
- 04 · 12 · 04.335
- Constellation Name
- Eridanus
- Z
- 0.003468 · 0.000017ned
- Dist Ly
- 17.887 ± 0.451 Mpcned
- Appmag V
- 10.65
Facts from the source article.
Lore & Background
NGC 1532 was discovered by James Dunlop on 29 October 1826. The galaxy is one of many edge-on spiral galaxies that possesses a box-shaped bulge, an indication that the bulge is actually a bar. Such bars are easy to detect in face-on galaxies, but in inclined galaxies like this one, careful analyses are needed to distinguish between bulges and bar structures.
The galaxy is clearly interacting with the amorphous dwarf galaxy NGC 1531. Tidal forces from this interaction have created unusual plumes above the disk of NGC 1532. NGC 1532 may possess several dwarf companion galaxies and is also an outlying member of the Fornax Cluster.
Three supernovae have been observed in NGC 1532: SN 1981A (Type II, mag. 13.5) discovered by Robert Evans on 24 February 1981; SN 2016iae (Type Ic, mag. 17.32) discovered by ATLAS on 7 November 2016; and SN 2016ija (Type II, mag. 16.5) discovered by the Distance Less Than 40 Mpc Survey (DLT40) on 22 November 2016.
Reader's Guide
NGC 1532's significance lies in its box-shaped bulge, which provides a clear example of how bars can be identified in edge-on spiral galaxies through careful analysis. Its interaction with the dwarf galaxy NGC 1531 offers a valuable case study of tidal forces and the formation of plumes above a galactic disk. The galaxy's membership in the Fornax Cluster, albeit as an outlying member, places it within a larger cosmological context. The three recorded supernovae—SN 1981A, SN 2016iae, and SN 2016ija—contribute to the understanding of stellar evolution and supernova rates in interacting systems. NGC 1532 is often compared to NGC 4631, another edge-on spiral galaxy interacting with a dwarf companion, highlighting its role in comparative studies of galactic interactions.
Frequently Asked Questions
What is NGC 1532?
NGC 1532 is an edge-on barred spiral galaxy sitting roughly 58 million light-years from Earth in the constellation Eridanus. It was first recorded by James Dunlop on 29 October 1826.
What does the nickname "Haley's Coronet" refer to?
Haley's Coronet is an alternative name that has been attached to NGC 1532 in the astronomical literature. It gives the galaxy a more distinctive identity beyond its New General Catalogue number.
How do astronomers confirm NGC 1532 actually has a bar?
Because the galaxy is viewed almost perfectly edge-on, the bar cannot be seen as a simple elongated streak the way it would in a face-on spiral. Researchers instead detect the bar by noting the characteristic boxy profile of the central bulge, which betrays the underlying bar structure.
What is happening between NGC 1532 and NGC 1531?
NGC 1531 is a small, shapeless dwarf galaxy that NGC 1532 is actively gravitationally pulling on. The tidal forces from that ongoing interaction have produced unusual plumes of material rising out of the system.
Why do astronomers find NGC 1532 worth studying?
It is a prime example of how tricky it is to confirm a bar in a tilted galaxy, since the bar's signature is largely hidden by the viewing angle. Its live gravitational tug-of-war with NGC 1531 also makes it a natural laboratory for studying tidal interactions in real time.
More in NGC Objects, Part 3 1-24
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