Table of Contents

• Perspectives
• Interesting Images
• Radio Telescopes
• Radio Astronomy sites

Perspectives

• A good point to begin thinking about radio astronomy is to gaze at our own Milky Way galaxy. This is a composite image from the perspective of Earth. To explore finer detail and view the satellite galaxies, peruse the GigaGalaxy Zoom project from the European Space Agency. The Milky Way is complex and has a structure very difficult for us to determine. Mapping of hydrogen atom clouds at 1.4 GHz (21 cm wavelength), a frequency at which much of the galaxy is transparent, has been crucial to this effort. The most recent model for our galaxy is that of a barred spiral, much like NGC 1073 though larger, with many fascinating features such as gamma-ray bubbles.
• Radio telescopes, such as ALMA in the Atacama desert and the VLA in New Mexico, operate at frequencies from 0.01 to 500 GHz and can detect atomic and molecular clouds in stunning regions of our galaxy, image the hugely energetic radio galaxy NGC 383 or observe pulsars.

Interesting Images

• Sun at 1.4 GHz
• 1.4 GHz image of synchrotron radiation from relativistic electrons circulating around Jupiter
• Supernova remnant at 1.4 GHz
• At 1.4 GHz, two spiral galaxies that have passed through each other
• M33, the Triangulum galaxy (3 Mly away) at 1.4GHz, with Doppler shifts relative to the center of mass Doppler shift. The UV image for comparison.
• Black hole belches 14 solar masses of plasma, at 8.4 GHz

Radio Telescopes

• Radio telescopes can operate only within certain frequency bands because the electromagnetic spectrum is congested with allocated bands.

Radio Astronomy sites

• The National Radio Astronomy Observatory has a very informative introduction to radio astronomy.