An exceptionally optical flare of BL Lac on 2022 Oct
ATel #15725; J. A. Acosta Pulido, M. Nievas Rosillo, J. Becerra Gonzalez (Instituto de Astrofisica de Canarias, Spain); M. I. Carnerero (Osservatorio Astrofisico di Torino, Italy)
on 27 Oct 2022; 09:04 UT
Credential Certification: Jose A. Acosta-Pulido (jap@iac.es)
Subjects: Optical, Blazar
Referred to by ATel #: 15730
We report on optical observations of BL Lac using the 0.4 m telescope network of Las Cumbres Observatory.
A sudden increase of flux was observed on 2022-Oct-20 0:45UT, w.r.t. the previous data taken 4 hours before. Our measurements show an increase in brightness of about 0.45 magnitudes in V and R bands. Afterwards, the source flux increases a bit further in the next 4 hours and then decreases by 0.2 magnitudes after 1 day. Our last observation on 2022-Oct-24 23:46UT shows a similar brightness level as before the flare occurred.
Note that the magnitudes reached at the observed maximum (R=11.52 and V=12.08) are above the dramatic outburst in 2020 Aug, as reported by Jorstad et al (2022, Nature, 609, 265).
The details of the measurements are as follows:
JD=2459870.92 - R=12.14, V=12.64
JD=2459871.53 - R=12.16, V=12.74
JD=2459872.36 - R=11.96, V=12.57
JD=2459872.53 - R=11.55, V=12.14
JD=2459872.70 - R=11.52, V=12.08
JD=2459873.73 - R=11.73, V=12.28
JD=2459876.70 - R=12.07, V=12.58
JD=2459873.73 - R=12.10, V=12.77
Another brightening in the optical range was reported in ATel #15684, happening in the days previous than reported here.
