The new activity period of blazar S4 0954+65 in 2023 September
ATel #16261; V. V. Vlasyuk, O. I. Spiridonova, A. S. Moskvitin, O. A. Maslennikova (Special Astrophysical Observatory of the Rus. Ac. Sci.)
on 29 Sep 2023; 04:51 UT
Credential Certification: Alexander Moskvitin (mosk@sao.ru)
Subjects: Optical, Blazar
Referred to by ATel #: 16331
We continued monitoring of the blazar S4 0954+65 since its last activity epoch at 2023 May-June. The main observations were provided using by 0.5-meter SAO RAS reflector due to some instrumental limitation of the our 1-meter telescope. Our instrumental setup at the 0.5-meter telescope was changed --- instead of 4K by 4K pixels front-illuminated CCD camera we started observations with smaller (512 by 512 pixels) but more efficient back-illuminated Andor DU-897 camera with the same filter set.
According to our data, the current activity period of the blazar have been started at first decade of September, when its brightness increased from R~15.5 mag (MJD=60189) to R~15.0 at MJD=60198. After local maximum R~14.45 mag at MJD=60203 brightness of blazar returned to quasi-quiet state at level R~15.2 mag at epochs MJD = 60204-60210.
At least, the object showed last significant brightness increase, reaching an R-band magnitude of about 13.7 at epoch MJD=60214 from value R=14.7, as was measured by us two days before. Now the blazar is undergoing some flux variations at this level.
Some signs of intraday variability were found by us and should be analyzed more accurately.
The most of data were taken under good weather condition (seeing about 2 arcsec) and have typical accuracy about 0.01 mags. The worse accuracy (up to 0.02 mag) is explaining by bright Moon sky within last days.
We strongly encourage further multi-wavelength studies.
