Views of our galaxy and the rest of the universe
at many wavelengths.

Alas, most of the images that I linked to have disappeared. Sorry about that. D. Soper

• radio, about 73 cm Predominantly from "synchrotron radiation" from moving electrons whose paths are bent by a magnetic field. [ASP, C. Haslam, Max Planck Institut fur Radioastronomie.]
• radio, 21 cm Maps neutral hydrogen gas ``HI''. [ASP, C. Jones and W. Forman]
• microwaves, 12 mm Maps ``microwave background'' from the birth of the universe (to be discussed later in this course.) [These data are from baloon flights. There is better data from a satellite known as COBE]. [ASP, D. Wilkinson]
• microwaves, 5 mm Maps carbon monoxide, CO, in molecular clouds -- cool, dense clouds of gas and dust where new stars can form. Top map shows CO versus galactic lattitude and longitude. Bottom map shows galactic longitude on the horizontal axis and velocity toward us or away from us along the vertical axis. [ASP, T. Dame]
• infrared , 12 to 100 micrometers. From slightly warm dust. [ASP, JPL/IRAS]
  • Red is 100 micrometers.
  • Green is 60 micrometers. (Recall that red + green = yellow to your eye).
  • Blue is 12 micrometers. (The blue band is from dust in our solar system.)
• infrared sources color coded by wavelength. [ASP, JPL/IRAS]
  • Blue are cool stars
  • Yellow-green are galaxies.
  • Red is patches of gas clouds.
• infrared, 1.25, 2.2, and 3.5 micrometers. Note how dust blocks the view of the cental bulge in the 1.25 micron picture. [COBE/DIRBE satellite picture]
• infrared, 1.25, 2.2, and 3.5 micrometers combined into one picture (central region only). [COBE/DIRBE satellite picture]
• visible light, 400 to 800 nanometers. We can see that we are in a disk of stars, but we can't see very far into it at this wavelength. [ASP, Lund Observatory]
• X-rays, 4 to 8 nanometers. with six very bright sources excluded from the map. It appears that there is a diffuse x-ray glow from all directions, with less in the plane of the galaxy where the x-rays are absorbed by the gas that resides there. [ASP, D. McCammon, D.N. Burrows, W. Sanders and W. Krauschaar]
• gamma-rays, 2 x 10^-15 m to 4 x 10^-17 m. . Mostly from collisions of high energy particles called ``cosmic rays'' with interstellar gas. Two neutron stars can also be seen. [ASP, European Space Agency COS-B satellite]