Search

Over 13600 continuum observations of extragalactic sources are presented. These observations of 157 sources at 22, 37 and 87 GHz more than doubles the millimeter observations of these sources. The data are between 1990.5 and 1995.5, and combined with our earlier published data they form a 15 year database.

From several southern hemisphere radio-wavelength monitoring programs, we have compiled multi-wavelength observations of a number of both EGRET-detected sources and sources with similar radio-properties that have not been detected by EGRET. The radio observations were made at 0.8, 2, 5, 8, 90 and 230 GHz, though not all sources were monitored at all wavelengths. The data are compared with EGRET data to the end of Cycle 4 (October 1995) in an effort to confirm previously reported correlations between activity at radio wavelengths and EGRET detections, and to investigate whether the non-EGRET-detected sources were in radio- and gamma-ray–quiet phases during this period.

Quasars have been monitored with the Metsahovi Radio Telescope since 1980 at 22 GHz and 37 GHz. During these years we have recorded numerous outbursts in our sample. Some of the outbursts are simple in nature, while others also seem to have fine structure. Can the outbursts be modelled in a simple way?

We analyze the time variability of compact radio sources at 22 and 37 GHz by using a structure function analysis. Our monitoring program in Metsahovi, Finland, includes a complete sample of bright, flat-spectrum extragalactic compact radio sources. For the structure function analysis we have selected 42 best-observed sources from this sample. In this subsample we have 14 BL Lac objects, 13 high-polarization quasars, 12 low-polarization quasars, two galaxies, and one empty field source. The structure function analysis exhibits very similar slopes for all sources, which is consistent with there being one basic physical mechanism of millimeter variability for all compact radio sources