Pursuing galaxy formation into the submillimeter
Dust in galaxies absorbs starlight and reradiates it at much longer wavelengths, and in very dusty galaxies most of the light emitted in the visible wavelengths may be reradiated into the far infrared at wavelengths of around 100 microns. For galaxies at large distances this light is further redshifted by the expansion of the Universe to the so-called submillimeter wavelengths, which may be observed from the ground. A new instrument --- the SCUBA array of bolometers on the JCMT 15 meter telescope --- has recently provided the necessary sensitivity to make measurements of such high redshift galaxies for the first time.
The first two blank field surveys --- one by our own US-Japanese team and the other by a UK team --- have shown that there are indeed luminous high redshift galaxies which emit most of their light in the submillimeter range, confirming earlier targeted observations. The results are important because they suggest that much of the high redshift star formation may be hidden to visual observations from optical observatories and HST. The pages here describe the new data and show its relationship to other information on the star formation history of our universe.