Hello, I am reading a fabulous (though somewhat older book) called "Intelligent life in the Universe" by s. Sagan and I.S. Shklovskii. They describe intense magnetic fields extending from the galactic core that channel interstellar gas and dust into the spiral arms which are the primary site of star formation. I'm looking for more sources that describe in more detail galactic magnetic fields and their implications for the large-scale circulation of gaseous material in the galaxy. I would think gasses and other elements thrown off at non-relativistic velocities in supernovae/star dying events are captured by galactic magnetic fields and channeled back into the spiral arms where another generation of stars may form. Any materials or info you folks know of that could expand on this topic is appreciated! (also if you know of a more recent book similar in scope and subject to "Intelligent life in the Universe" do mention it. It was written in 1963 and I'm sure there is much to be added).