Quenchings and Outbursts of Extragalactic Radio Sources: Nine Years of 3.3-mm Measurements and Comparisons with Centimeter-Wave Variations

The extragalactic variable radio sources 3C, 84, 3C 120, OJ 287, 3C 273, and BL Lac have been observed frequently at 3.3 mm for up to 9 years; the results are compared with 19-, 28-, 38-, and 45-mm observations. (1) The 3-mm variations are often rapid; significant information is lost if observations are not made every 1 - 3 days. (2) The correlation between the 3-mm and centimeter-wave variations of these five sources ranges from the 3-mm and centimeter-wave variations of these five sources ranges from high to almost non-existent; in general, the flatter the spectrum, the better the correlation. (3) The relationship between time lag and wavelength for possibly-connected outbursts appears to be characteristically different for different objects. (4) No pronounced 3-mm outbursts on a time scale of one to a few days were observed, but three sharp drops or 'quenchings' were. A list of other quenchings found in the literature is included. (5) The amplitudes of outbursts vary as lambda to the kth power, where k approx. -0.4, from 3.3 to 111 mm, a factor of 34. Results 4 and 5 may place significant new constraints on models. (Author) Original contains color plates: All DTIC and NTIS reproductions will be in black and white. Prepared in cooperation with International Business Machines Corp., Milwaukee, WI and California Polytechnic State Univ., San Luis Obispo, CA.