Spiral galaxies like the Milky Way can be thought of as thin disks. The disk is believed to be fundamentally axisymmetric (circular symmetry in the plane). When viewed at an angle other than face-on (from above or below the plane exactly), the circular disk appears elliptical. The greater the ellipticity, the more the galaxy's disk in inclined with respect to our line of sight.
In practice, we measure the ellipticity from examining the contours of equal surface brightness (isophotes) in an image
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment