IRIS 100 micron brightness (Miville-Deschênes & Lagache 2005) on a logarithmic intensity scale from 1 to 105 MJy sr-1. The red and yellow emission is in from dust near the Galactic plane; the blank area was not observed. The red lines mark I-GALFA survey boundaries.
The image on this page shows thermal infrared emission from starlight-heated dust particles in the gas I-GALFA will observe. The red lines mark the minimum survey boundaries needed to map within 10 degrees of the Galactic equator, which includes all the gas down in the plane where new stars form, plus material up above the plane that has either been pushed there by stellar winds or supernovae or is falling down from clouds orbiting the Galactic center.
I-GALFA will see atomic hydrogen gas with a similar amount of angular detail to that visible here in infrared dust emission, and it is sensitive enough to see every dust filament in the gas. But because I-GALFA is observing the hydrogen spectral line and its doppler shift, this adds a velocity dimension that will tell us how each dust feature is moving. (Comparisons of hydrogen gas and dust emission in other parts of the sky are available for the Perseus and MBM 53-55 molecular cloud regions.)
The first field to be observed is at the bottom of the red-enclosed area, where we hope to examine a variety of structures down in the disk and at higher latitudes at many different distances along the line of sight. One of these is Loop I, a nearby expanding shell from an old supernova remnant, the edge of which lies near 18h Right Ascension.