Optical follow-up of B2 1015+35B
ATel #16814; Roberto Nesci (INAF/IAPS), Antonio Vagnozzi (MPC589)
on 14 Sep 2024; 06:59 UT
Credential Certification: Roberto Nesci (roberto.nesci@inaf.it)
Subjects: Optical, Gamma Ray, AGN, Gamma-Ray Burst, Quasar
After the announcement of a strong Gamma-ray flare of the Flat Spectrum Radio Quasar B2 1015+35B in ATel #16812 we observed the source with the 30cm telescope of the Santa Lucia di Stroncone Observatory (MPC 589) on 2024-09-14 (MJD 60567) with the R and I (Cousins) filters, respectively for 3000 s and 480 s. Nearby comparison stars were taken from the PanStarrs DR1 catalog (VIZIER II/349, Chambers+ 2016) adopting their rmag and imag magnitudes. Several satellite tracks are present in our images, but luckily they do not cross the Quasar.
B2 1015+35B was detected at rmag=17.15 +/-0.07, imag=16.89 +/-0.11. The PanStarrs catalog values are rmag=17.72, imag=17.85, likely not simultaneous.
The light curve of the source, available since October 2015 from the ATLAS forced photometry service, shows a slow monotonic luminosity increase with some flares of about half magnitude and about one month long, but stops on June 2024 due to the solar conjunction. A linear extrapolation of the trend to the present date gives rmag=17.28, which is not very different from the observed value.
The Quasar reached rmag=16.8 on previous flares (MJD 59304, 59667, 60073), when no Gamma-ray flares were detected by Fermi-LAT according to ATel #16812: the observed present value suggests therefore that there is no correlation between the optical and the Gamma-ray luminosity of the source, at variance with most BL Lac objects.
