OBSERVATIONS OF JUPITER AT 3.5 CM AND 6.0 CM ASSOCIATED WITH THE IMPACT OF COMET-P SHOEMAKER-LEVY-9

Jupiter was observed before, during, and after the July 1994 impacts o f Comet P/Shoemaker-Levy 9. Observations were made with the HartRAO 26 -m antenna at 3.5 and 6.0 cm. In agreement with observations at other wavelengths, an increase in the total flux density was seen at both wa velengths during the impact week, followed by a slow decay. At 6.0 cm the nonthermal flux density was found to increase by 1.1 +/- 0.1 Jy (s imilar to 40%) and at 3.5 cm by 1.5 +/- 0.1 Jy (>75%). The relaxation of the flux density to preimpact levels was found to decay with an exp onential lifetime of 215 +/- 10 days at 6.0 cm and at 300 +/- 15 days at 3.5 cm. The exponential decay time is considerably shorter, however , during the first few months after the impacts. In addition, pronounc ed variations in the flux density at both wavelengths were seen during the first two months after the impacts, with a significant increase i n the flux density about 85 days after the last impact. (C) 1998 Acade mic Press.