IRAS Images of the Galactic Plane
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.
Feature
Locator
