This poster is a collection of classic Magellanic Galaxies; that is, those classified as Barred Magellanic Spirals (SBm). The prototype and namesake is the Large Magellanic Cloud (LMC). Although many other types of Magellan galaxies exist, including unbarred ones, the SBm galaxies are the most studied and, in many ways, the most interesting.
I used to think of these SBm galaxies as irregular, but a more accurate way to describe them is asymmetric. (On the other hand, the Small Magellanic Cloud can be thought of as irregular). In addition to being asymmetric, SBm galaxies usually have the following characteristics:
- Off-center white stellar bar
- One dominant arm
- Blue star formation areas
- Diameter from 15,000 to 40,000 light years
Scientists are learning more about these galaxies every year. Although much studied, the following key questions still exist:
1. Are the bars in Magellanic spirals similar to the bars in spiral galaxies? Early work indicates that they are not - the bar only appears to have a small impact on the gas kinematics in the central galaxy region, unlike barred spirals.
2. How significantly do companions impact their formation, particularly their asymmetric nature? A number of years ago, it was believed that a common trait of these galaxies is the existence of a companion, but that is no longer the case. Some Magellanic galaxies do have small companions but many do not.
The coming years will shed much more light on these interesting small galaxies. If you would like to read more about any of these objects, each of the objects in the poster has previously been uploaded and described individually on Astrobin. They all reside in my
Astrobin Classic SBm Magellanic Galaxies Collection.
If you would like to access all my DSO compilation posters, please click
here.
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