Millimeter and submillimeter observations of nearby radio galaxies

Radio galaxies are often observed to be strong long wavelength infrared sources. Twenty-six radio galaxies with strong compact cores were observed at wavelengths near 1 mm with the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. The detections and upper limits establish the presence of excess infrared emission for almost all of the galaxies in the sample. The exceptions are the BL Lac objects, which have smooth continuous spectra from radio to infrared wavelengths. The spectral energy distributions of the infrared emission from the radio galaxies favor a thermal origin due to emission from cool interstellar dust. The amounts of dust inferred to be present approach those observed in large spirals.