I have been trying to calculate the distances to the spiral arms (neutral Hydrogen clouds) and our equation seems to work perfectly for longitudes 0<l<90 but doesn't seem to work for the outer galaxy (i.e. between 90<l<270) - we get distances but they're not correct. After reading a lot of...
Thanks for the reply mfb. We are indeed assuming that the velocities of the Sun and the cloud are the same (although we have only observed the velocity of the cloud along the line of sight) - this is due to the rotation curve of the Milky Way being approximately constant due to the extra matter...
Homework Statement
Using a radio telescope we are recording data from the galactic plane at the 1420.4MHz frequency of neutral Hydrogen - we are aiming to create a polar map of the Hydrogen in the Milky Way. When looking through a cloud of Hydrogen (i.e. a spiral arm) the frequency observed can...