Again a strong increase of brightness of the AGN S4 0954+65

ATel #15517; N. Bader, M. Brown, F. Hemrich, B. Horst, M. Pospischil, M. Rauschert, D. Reinhart, K. Schoch; J. Seufert, R. Steineke, P. Schweitzer, N. Zottmann, M. Feige, C. Lorey (all Friedrich-Koenig-Gymnasium / Hans-Haffner-Sternwarte, Wuerzburg, Germany) L. Kunkel, K. Mannheim (all Universitaet Wuerzburg, Germany), D. Elsaesser (TU Dortmund, Germany) V. Vlasyuk, O. Spiridonova, A. Moskvitin, O. Maslennikova (Special Astrophysical Observatory of Rus. Ac. Sci.; Russia) A. Marchini (Astronomical Observatory, University of Siena, Italy); H.-E. H. Choi, N. Du, M. L. Hulburt, T. J. Balonek (Foggy Bottom Observatory, Colgate University, Hamilton, NY, USA); G. Bonnoli (INAF - Brera Astronomical Observatory, Italy); C. M. Raiteri, M. Villata (INAF, Osservatorio Astrofisico di Torino, Italy).
on 18 Jul 2022; 23:16 UT
Credential Certification: Dominik Elsaesser (dominik.elsaesser@tu-dortmund.de)

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Since the beginning of April this year the BL Lac-type object S4 0954+65 (RA: 09 58 47.2452 Dec: +65 33 54.8194; ICRS J2000) has been showing increased activity both in the optical (ATel #15322; ATel #15344; ATel #15376; ATel #15380) - here also in polarized light (ATel #15414; ATel #15419) - and in the gamma-ray regime (ATel #15375).
In the optical the object reached new records in the R-band on 21 April - JD 2459691.24 with 13.20 mag (ATel #15344) as well as on 13 May - JD 2459712.6873 with 12.72 mag (ATel #15380).
In the following weeks the brightness decreased and moved in a range of about 14.7 to 15.8 mag (R-band).
Since 11 July the brightness of this object has been steadily increasing again and now has reached about 13.4 mag.

We announce the following brightness values (R band):
Hans Haffner Observatory (HHO); Foggy Bottom Observatory (FBO); Special Astrophysical Observatory (SAO); Observatory of the University of Siena (Siena);
JD 2459768.3555: 15.735 ± 0.007 (SAO)
JD 2459769.2688: 15.577 ± 0.009 (SAO)
JD 2459770.3593: 15.114 ± 0.009 (SAO)
JD 2459771.7459: 15.23 ± 0.05 (FBO)
JD 2459772.3889: 15.293 ± 0.013 (HHO)
JD 2459773.7361: 15.75 ± 0.04 (FBO)
JD 2459775.4853: 14.836 ± 0.010 (HHO)
JD 2459775.7265: 14.71 ± 0.02 (FBO)
JD 2459776.2767: 14.570 ± 0.005 (SAO)
JD 2459776.4267: 14.312 ± 0.006 (HHO)
JD 2459776.5424: 14.283 ± 0.008 (HHO)
JD 2459776.5772: 14.204 ± 0.010 (HHO)
JD 2459777.4228: 14.000 ± 0.004 (HHO)
JD 2459777.4553: 13.930 ± 0.005 (HHO)
JD 2459778.3775: 13.680 ± 0.008 (HHO)
JD 2459778.4110: 13.662 ± 0.007 (HHO)
JD 2459778.4413: 13.746 ± 0.007 (HHO)
JD 2459778.4828: 13.731 ± 0.004 (HHO)
JD 2459779.33328: 13.362 ± 0.010 (Siena)
JD 2459779.3722: 13.449 ± 0.006 (HHO)
JD 2459779.38715: 13.439 ± 0.007 (Siena)
JD 2459779.3886: 13.472 ± 0.004 (HHO)


The observations were conducted within the framework of the WEBT Collaboration (https://www.oato.inaf.it/blazars/webt/) using a 0.3 m telescope at the Astronomical Observatory of the University of Siena (https://www.dsfta.unisi.it/en/research/labs/astronomical-observatory), with a 0.4 m telescope at the Foggy Bottom Observatory (https://observatory.colgate.edu/), with a 0.5-meter RC telescope of Special Astrophysical Observatory of Rus.Ac.Sci. (https://www.sao.ru/Doc-en/index.html) and with a 0.5 m telescope at the Hans-Haffner Observatory (https://schuelerlabor-wuerzburg.de/en/observatory/).
All data were recorded with standard R filter and analysed according to the specifications of the WEBT Collaboration (https://www.oato.inaf.it/blazars/webt/0954658-s4-095465/).