Optical brightening of the Blazar S2 0109+22
ATel #16783; M. Heidemann, G. Manhalter, O. Domann, D. Kuberek, L. Bertsch, S. Duerr, R. Goldbach, M. Hensel, M. Kardasch, L. Lehmann, N. Mildner, F. Pfeuffer, G. Rinke, N. Zottmann, R. Steineke, M. Feige, D. Reinhart, C. Lorey (all Hans-Haffner-Sternwarte, Friedrich-Koenig-Gymnasium, Wuerzburg, Germany) F. Eppel, J. Hessdoerfer, M. Kadler, L. Kunkel, K. Mannheim, F. Roesch (al University of Wurzburg, Germany) D. Elsaesser (TU Dortmund, Germany)
on 21 Aug 2024; 14:30 UT
Credential Certification: Dominik Elsaesser (dominik.elsaesser@tu-dortmund.de)
Subjects: Optical, AGN, Blazar
Referred to by ATel #: 17025
The BL Lac object S2 0109+22 (also QSO B0109+224, QSO HB89 0109+224, or GC 0109+224) with the ICRS coordinates (ep=J2000) RA 01 12 05.825 and Dec +22 44 38.786 (optical), and redshift z = 0.265 (all data from the SIMBAD astronomical database: http://simbad.u-strasbg.fr/simbad/ ) showed a high brightness, reaching R = 13.798 mag at JD = 2460542.6211 (20 August 2024), in the last nights in the R-band. A similarly high optical brightness in the R-band was last measured by our team for this object in June 2023 (ATel #16093).
In recent months, the brightness of this blazar in the R-band has fluctuated between 15.4 and 14.4 mag, although the time series is not complete as we were unable to observe the object between the end of March and the end of June due to the geographical location of the Hans Haffner Observatory.
Within one month, the average brightness increased from slightly brighter than 15 mag (14.996 at JD = 2460512.5624) by about 1.2 mag.
Although the measured brightness values are not the overall highest measured for this object (see Ciprini et al., full reference given below), the rapid increase of 0.2 mag within three days still appears remarkable.
So, we here report the following (preliminary) magnitudes in the R-band, and encourage further observations:
JD 2460512.5624 14.996 ± 0.035
JD 2460516.5653 14.822 ± 0.033
JD 2460525.5688 14.296 ± 0.006
JD 2460528.5807 14.560 ± 0.006
JD 2460533.5434 14.467 ± 0.005
JD 2460534.4617 14.138 ± 0.006
JD 2460537.5915 14.188 ± 0.005
JD 2460538.5948 14.025 ± 0.004
JD 2460539.5949 14.001 ± 0.005
JD 2460542.4095 13.851 ± 0.015
JD 2460542.5274 13.827 ± 0.011
JD 2460542.6165 13.821 ± 0.009
JD 2460542.6211 13.798 ± 0.009
Comparison stars and their magnitudes were taken from S. Ciprini et al.: Optical variability of GC 0109+224; A&A 400, 487-498 (2003).
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) and a Moravian G4-16000 camera at the school and university observatory Hans-Haffner-Sternwarte in 97265 Hettstadt, Germany (https://schuelerlabor-wuerzburg.de/en/observatory/).
Hans-Haffner-Sternwarte
