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The Blazar S5 0716+714 shows increased optical activity and the highest brightness in over 3 years

ATel #16980; C. Lorey, R. Steineke, S. Duerr, M. Graef, N. Mildner, F. Pfeuffer, G. Rinke, N. Zottmann, M. Feige, D. Reinhart (all Hans-Haffner-Sternwarte, Friedrich-Koenig-Gymnasium, Wuerzburg, Germany) F. Eppel, J. Hessdoerfer, M. Kadler, K. Mannheim, F. Roesch (all University of Wurzburg, Germany) D. Elsaesser (TU Dortmund, Germany)
on 15 Jan 2025; 19:07 UT
Credential Certification: Dominik Elsaesser (dominik.elsaesser@tu-dortmund.de)

Subjects: Optical, AGN, Blazar

Referred to by ATel #: 16984, 16995

The blazar S5 0716+714 (ICRS coord. ep. = J2000: RA 07 21 53.45; Dec +71 20 36.36) shows an increase in the optical spectral range after years of rather weak activity.
While the object showed increased activity in numerous wavebands in the months from late 2017 to early 2019 (see ATel # 11100 -gamma ray, ATel #11107, ATel #11339, ATel #11676, ATel #11725, ATel #12298 - all optical, ATel #12682 - NIR), its (optical) activity decreased sharply until early 2019. In 2020 and 2021, S5 0716+714 then showed increased activity again with brightness values of over 12.5 mag in some cases (R-band). In the fall of 2021, high brightness values were reached once again, but did not quite reach 12.5 mag (R-band). After that, the activity of this AGN (at least in the optical range) increasingly calmed down and, with a few exceptions, the AGN showed brightness values weaker than 13 mag (R-band) with a - for this object -small downward fluctuation range of max. 1.5 mag.
Since the late Summer of 2024, the brightness has increased again and now reached a brightness of 12.568 ± 0.004 on the night of 12 to 13 January (JD: 2460688.4882), which has not been seen for over three years, most recently on the night of 2 to 3 October 2021; JD: 2459489.5161 with 12.558 ± 0.004 (R-band).
It is also remarkable that S5 0716+714 has shown an unusually large variation in brightness on short time scales in recent weeks.
In previous intra-night measurements that we carried out a few years ago, we were able to observe slow, continuous changes with an amplitude in the R-band of about 0.1 mag in one night. In recent weeks, S5 0717+714 has shown strong changes with amplitudes of 0.2 to almost 0.5 mag within a few hours in some nights.

Perhaps a new phase of increased activity is on the horizon for this object, which is why we want to encourage increased observations of this blazar in as many wavelength ranges as possible.


Here, we report the following preliminary R-band magnitudes:
JD 2460668.2412 13.212 ± 0.008
JD 2460671.3620 12.996 ± 0.003
JD 2460671.6631 13.100 ± 0.003
JD 2460672.2788 12.823 ± 0.003
JD 2460672.4148 13.033 ± 0.003
JD 2460672.5333 13.071 ± 0.003
JD 2460672.5881 13.088 ± 0.003
JD 2460672.6339 13.210 ± 0.003
JD 2460672.6453 13.253 ± 0.003
JD 2460672.6539 13.266 ± 0.003
JD 2460672.6582 13.261 ± 0.003
JD 2460672.6668 13.275 ± 0.003
JD 2460672.6796 13.308 ± 0.003
JD 2460672.7202 13.288 ± 0.003
JD 2460672.7438 13.285 ± 0.004
JD 2460680.2714 13.190 ± 0.008
JD 2460680.3262 13.151 ± 0.011
JD 2460686.3307 12.908 ± 0.004
JD 2460686.4097 12.840 ± 0.003
JD 2460687.2244 13.021 ± 0.023
JD 2460688.2821 12.786 ± 0.004
JD 2460688.3762 12.678 ± 0.004
JD 2460688.4882 12.568 ± 0.004
JD 2460688.6126 12.655 ± 0.004
JD 2460688.7401 12.698 ± 0.005
JD 2460689.2165 12.719 ± 0.015
JD 2460689.2291 12.715 ± 0.015
JD 2460690.1986: 13.193 ± 0.011


These measurements are carried out as part of the long-term AGN monitoring program of the Naturwissenschaftliches Labor fuer Schueler am Friedrich-Koenig-Gymnasium (FKG), the Universitaet Wuerzburg, and TU Dortmund University. The optical data were acquired through a Bessel R filter (Chroma) with the 0.5m CDK-astrograph (PlaneWave Instruments) and a Moravian C4-16000EC camera at the school- and university observatory Hans-Haffner-Sternwarte in 97265 Hettstadt, Germany (https://schuelerlabor-wuerzburg.de/en/observatory/).

Hans-Haffner-Sternwarte