The Radio Sky: Introduction

Introduction -- Components -- Visualization -- Links

This interactive module allows you to view the whole sky at various radio and microwave frequencies, and to plot the frequency spectrum at different locations on the sky to explore how different physical components of the Galaxy vary spatially.

Why is the large-scale radio sky interesting?

Diffuse emission, or radiation that is spread out instead of concentrated in one place, can tell us about the overall structure in the galaxy. Where in the Milky Way are free electrons located? How energetic are they? What can they tell us about the Galactic magnetic field? Do their locations correspond with the distribution of neutral Hydrogen? How about interstellar dust? What is the temperature off the dust? Is it spinning? Learning the relative strengths and distributions of these important components of our Galaxy can teach us about how the Milky Way formed and why galaxies have the structure we see.

If, on the other hand, you are interested in learning about what is beyond the Galaxy (for example, reionization or CMB studies), it is important to remove the Milky Way's contribution to the sky. In this case, being able to accurately model various Galactic "foreground" components is crucial because often the Galaxy will be many orders of magnitude brighter than the desired cosmological signal.

To learn about the components and processes that emit radio emission, click on the Components tab. To see the sky in radio frequencies, click on the Visualization tab.

The sky as seen by WMAP at 33 GHz, showing both the Galaxy and the CMB.

This website was created for Harvard's Astronomy 201b class: Interstellar Medium and Star Formation.