File:Analyzing Hot DOG Galaxies (PIA15815).jpg

English: This plot illustrates the new population of "hot DOGs," or hot dust-obscured objects, found by WISE. The purple band represents the range of brightness observed for the extremely dusty objects. These powerful galaxies, which host active supermassive black holes at their cores, pour out enormous amounts of light at infrared wavelengths, while their visible light is blocked by dust.

Visible light we see with our eyes has shorter wavelengths than one micron, while the longest wavelengths shown here come from observations with the Caltech Submillimeter Observatory on Mauna Kea, Hawaii. The red line shows the brightness profile, or spectral energy distribution, of a proto-typical infrared luminous galaxy.

The small images near the top show more familiar objects at a range of temperatures from 70 Kelvin, or minus 330 degrees Fahrenheit, for liquid nitrogen, to 1,500 Kelvin, or 2,240 degrees Fahrenheit, for lava. The energy from hotter objects peaks at shorter wavelengths.

The extreme WISE objects represented by the purple band are much brighter -- and peak at much shorter, or hotter, wavelengths -- than the typical infrared luminous galaxy, hence their nickname: hot dust-obscured galaxies or Hot DOGs.