This poster is the 46th in my series of compilation posters. All of the posters are contained in my
Astrobin Poster Collection.
This poster is a collection of galaxy barlenses. Barlenses are one of the most recent areas of astronomy study. The first papers recognizing barlenses were published about a decade ago. Despite being only a recent phenomenon, barlenses are prevalent in the universe. About half of the barred galaxies that I have imaged have barlenses.
One of my previous posters addressed
pseudobulges, also called disk-type bulges. These pseudobulges are recognized by their distinctive X-pattern in the edge-on view. This pattern is also often described as peanut-shaped or Figure 8 shaped. The pattern is due to the inherent vertical instability of the bar and the resulting periodic, out-of-disk plane orbits of stars in the bar region.
Viewed face-on, this pattern is now recognized as a barlense. A barlense is a distinctive shape of a bright oval lens superimposed on a long, narrow, bright bar of similar brightness. The oval lens is about 1/2 the length of the bar. A bright core is always present and is about 1/4 the length of the oval lens. In comparison to a normal bar, the bar of a barlense is much brighter. Also, no oval lens is present in a standard bar.
There are still many questions about barlenses and their impact on the galaxies that contain them. My observation is that barlenses more often result in bright inner rings and dim outer disks. Also, whenever I find a galaxy with a
closed outer ring, which is a bit rare, it almost always has a barlense.
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 Galaxies - Bar (Barlens) Collection.
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