Statistical rotational angular speed of DAM emissions. Panel (a): median values and error bars indicating the time uncertainty when considering ±4 min on the radio dynamic spectrum. The rotational angular speed of Io and Jupiter are represented by a dashed line and a solid line, respectively. Panel (b): histogram of the averaged rotational angular speed of DAM emissions in bins of 0.05 Ω_J. These events can be divided into Io-related (blue bars) and non-Io-related (orange bars) DAM emissions.