Together with the TELAMON group, our AGN Monitoring Group has published another Astronomers Telegram – the 31st to date!
Astronomers Telegram #17508 describes a flare of the BL Lac object S2 0109+22.
This blazar is known both as an intense radio source and as a source of high-energy gamma radiation. This object is also very active in the optical spectral range and may exhibit periodic brightness fluctuations here.
From the beginning of October, the apparent optical brightness of this object increased steadily, reaching a record-breaking brightness in the optical spectral range of 13.364 mag in the R band on the night of 21 to 22 November this year.
This increase in optical activity, measured at the Hans Haffner Observatory, corresponds very well with the increase in radio emission from this object, which was measured by the TELAMON group using the Effelsberg 100 m radio telescope.
In high radio frequencies in the range of 19–45 GHz, the TELAMON group was able to detect a continuous increase in flux density of a good 1.2 Jy (14 mm) over the past six months. These flux densities are higher than they have been for over two years.
Since the activities in both spectral ranges match very well, a wonderful short report could be published using the data from Effelsberg and Hettstadt.
