The flat spectrum radio quasar OP 313 is again in a very bright optical state at R=13.7
ATel #16951; Alessandro Marchini (Astronomical Observatory, University of Siena - Italy); Leonardo Stiaccini, Gaia Verna (Department of Physical Sciences, Earth and Environment (DSFTA), University of Siena - Italy); Simone Leonini, Massimo Conti, Paolo Rosi, Luz Marina Tinjaca Ramirez (Montarrenti Observatory, Sovicille (Siena - Italy)); Pietro Aceti, Massimo Banfi (Seveso Astronomical Observatory, Seveso (Monza e Brianza - Italy)); Giacomo Bonnoli (INAF - Brera Astronomical Observatory)
on 15 Dec 2024; 12:52 UT
Credential Certification: Giacomo Bonnoli (giacomo.bonnoli@inaf.it)
Subjects: Optical, X-ray, Gamma Ray, VHE, Request for Observations, AGN, Blazar, Transient
Two nights ago, we observed the flat spectrum radio quasar OP 313 (R.A. = 197.619 deg, Decl. = +32.345 deg; J2000; Johnston et al. 1995, AJ, 110, 880) at redshift z=0.997 (Schneider et al. 2010, AJ, 139, 2360) from the Astronomical Observatory of the University of Siena. This observation was part of the prolonged follow-up of the flare detected in early November (see ATel#16891) and comes right after the recent announcement of another gamma-ray flare published by the FERMI/LAT Collaboration in ATel#16940.
On 2024 Dec. 12.18 we detected a bright optical state at R=13.70(0.01) in the Johnson-Cousins photometric system. Quoted uncertainty is statistical only.
In the past weeks, our monitoring found the source in significantly dimmer states, with e.g. R=14.75(0.02) on Nov. 23.20; this indicates a clear rebrightening of the optical state, in agreement with the analogous recent evolution in the gamma-ray band. Furthermore, this optical rebrightening is likely very recent (a few days old at most) given that the publicly available lightcurve provided by the Tuorla Observatory at https://users.utu.fi/kani/1m/B2_1308+32.6.html still on Dec. 4th reports an optical magnitude dimmer than R=14.5.
The full data set, containing our measurements of the blazar OP 313 in the V, R, and I filters of the Johnson-Cousins photometric system obtained since the beginning of 2024, is under study and can be made available upon request. A publicly available plot of these data is linked at the end of this ATel. The observations have been carried out with the 0.30 m telescope at the Astronomical Observatory of the University of Siena (IAU MPC observatory code K54), the 0.53 m telescope at Montarrenti Observatory (C88) and the 0.30 m telescope at Seveso Astronomical Observatory (C24).
Any enquiry on these observations can be addressed either to Alessandro Marchini (marchini@unisi.it) or to Giacomo Bonnoli (giacomo.bonnoli@inaf.it). We will continue monitoring the source in the following nights. Multi-wavelength follow-up is encouraged.
Brief descriptions of the instrumental setups used for the reported observations are available at the official webpage of the Astronomical Observatory of the University of Siena, on the website of the Unione Astrofili Senesi and on the page of the Seveso Astronomical Observatory within the website of the Whole Earth Blazar Telescope .
Optical observations of the blazar OP 313 since the beginning of 2024, performed with the telescopes of the Astronomical Observatory of the University of Siena, the Montarrenti Observatory and the Seveso Observatory
