M. Yoneda

We analyse the light curve in the R band of the blazar OJ287, gathered during the 2015/2016 observing season. We did a search for quasi-periodic oscillations (QPOs) using several methods over a wide range of timescales. No statistically significant periods were found in the high-frequency domain both in the ground-based data and in Kepler observations. In the longer-period domain, the Lomb–Scargle periodogram revealed several peaks above the 99% significance level. The longest one—about 95 days—corresponds to the innermost stable circular orbit (ISCO) period of the more massive black hole. The 43-day period could be an alias, or it can be attributed to accretion in the form of a two-armed spiral wave.

We analyse the light curve in the R-band gathered during the 2015/16 observing season of OJ287. We did a search for QPOs using several methods in wide time domain. No statistically significant periods were found in the high frequency domain both in the ground data and also in K2 observations. In the longer periods domain the Lomb-Scargle periodogram revealed several peaks above the 99\% significance level. The longest one, about 95-day, corresponds to the ISCO period of the more massive SMBH. The 43-day period could be an alias or can be attributed to accretion in the form of two armed spiral wave.

Monitoring observations of Jupiter's sodium nebula and [SII] 673.1 nm emission from the Io plasma torus were made for 20 days in 2003. During these observations, the brightness of the sodium nebula showed a small enhancement which seemed to be caused by Io's volcanic outburst. During this enhancement, [SII] 673.1 nm brightness and the ion temperature (scale height) along Jupiter's magnetic fields did not show any significant change, but magnetic flux tube content of S⁺ ion was calculated from the [SII] 673.1 nm brightness and the scale height, and an increase of the ion flux tube content was clearly identified. Thus, increase of supplied plasma from Io seems to be reflected in both plasma density and ion temperature. We conclude that Io's volcanic enhancement with a duration time of a few days can change Jupiter's inner magnetospheric environment in aspects of both ion density and temperature.