IRAS Images of the Galactic Plane  

The images shown below were downloaded from the Skyview Virtual Observatory. They are IRAS maps of 
the Galactic plane in the direction of galactic coordinates (l,b) = (80°, 0°), at each of the four IRAS    wavelengths (12, 25, 60 and 100 µm). The maps on the left have a field of view of 10° x 10°, the ones on 
the right 30° x30°. 

The images show a triangular feature. The position of the feature is indicated by the locator figures at the top. The color scale of the images is the default ('Stern special') scale used by the Skyview Virtual Observatory. The images have not been processed in any way.  

The triangular feature can be interpreted as the imprint of a caustic ring of dark matter upon the gas and  dust in the Galactic disk. See astro-ph/0109296. The ring has radius 8.3 kpc. The images show the IRAS maps in a direction tangent to the ring. Looking in the tangent direction enhances the appearance of the cross-section of the ring. The cross-section of a caustic ring of dark matter is a "elliptic umbilic" catastrophe. This catastrophe has the shape of a triangle except that the vertices are cusps instead of angles. The gas and dust responds to the gravitational field of the dark matter caustic. The gravitational field is smoother than the caustic but retains its triangular shape.

The caustic rings of dark matter are predicted to lie in the Galactic plane and to be oriented such that one of the vertices points away from the galactic center. The triangular feature in the IRAS maps has these properties. 

To see larger size, click on the thumbnail
10° x 10°
30° x 30°
12 µm 
25 µm 
60 µm 
100 µm 

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