Follow-up of the ongoing exceptional flare of the FSRQ B2 1420+326 in the R and V optical bands
ATel #17874; Alessandro Marchini (Astronomical Observatory, DSFTA, 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)); Ivo Peretto, Giovanni Furlato, Giuseppe Peretto, William Rivato (MarSEC Observatory, Marana di Crespadoro (Vicenza - Italy)); Giacomo Bonnoli (INAF - Brera Astronomical Observatory, Milan - Italy).
on 6 Jul 2026; 00:30 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Gaia Verna (gaia.verna@unisi.it)
Subjects: Optical, AGN, Blazar, Transient
We confirm the unprecedent optical flare of the flat-spectrum radio quasar B2 1420+326, also known as OQ 334 and 4FGL J1422.5+3223 (R.A. = 14 22 30.38, Dec. = +32 23 10.44; J2000; Gaia Collaboration 2021, A&A, 649, A1) at redshift at z = 0.682 (Hewett & Wild 2010, MNRAS, 405, 2302). The blazar was recently reported to be flaring in the R-band (ATel#17873).
We confirm the exceptionally high magnitude of 12.65 in the R-band last night. In addition, we report the corresponding magnitude of 13.09 in the V-band.
The following table reports the brightness recorded in the R-band and in the V-band of the Johnson-Cousins photometric system during the last month. Quoted uncertainty is statistical only.
Civil Date (UT) Mag (Err) Band - Observatory
2026 June 03.905 13.60 (0.01) V - Montarrenti
2026 June 06.911 13.44 (0.01) V - Montarrenti
2026 June 08.885 13.66 (0.01) V - Montarrenti
2026 June 11.883 14.10 (0.01) V - Siena
2026 June 12.867 14.07 (0.01) V - Siena
2026 June 14.922 13.91 (0.02) V - Montarrenti
2026 June 16.868 13.83 (0.01) V - Montarrenti
2026 June 18.910 13.96 (0.01) V - Montarrenti
2026 July 03.889 13.32 (0.01) V - Siena
2026 July 04.907 13.17 (0.01) V - Siena
2026 July 05.740 13.09 (0.01) V - Montarrenti
2026 June 03.845 13.19 (0.01) R - Siena
2026 June 03.905 13.17 (0.01) R - Montarrenti
2026 June 06.913 13.02 (0.01) R - Montarrenti
2026 June 06.943 12.97 (0.01) R - MarSEC
2026 June 07.705 13.11 (0.01) R - Siena
2026 June 08.850 13.25 (0.01) R - Siena
2026 June 08.885 13.24 (0.01) R - Montarrenti
2026 June 11.873 13.67 (0.01) R - Siena
2026 June 12.868 13.65 (0.01) R - Siena
2026 June 13.873 13.53 (0.01) R - Siena
2026 June 14.922 13.47 (0.01) R - Montarrenti
2026 June 14.935 13.48 (0.01) R - Siena
2026 June 16.869 13.41 (0.01) R - Montarrenti
2026 June 18.910 13.53 (0.01) R - Montarrenti
2026 July 02.928 13.09 (0.01) R - Siena
2026 July 03.889 12.87 (0.01) R - Siena
2026 July 04.907 12.72 (0.01) R - Siena
2026 July 05.868 12.65 (0.01) R - Montarrenti
A publicly available plot of the B2 1420+32 data we collected in the last two months is available at
this webpage.
Observations were conducted from the 0.30 m telescope of the Astronomical Observatory of the University of Siena (Siena, Italy - IAU MPC observatory code K54), the 0.53 m telescope at Montarrenti Observatory (Sovicille, Italy - C88) and the 0.36 m telescope of the Marana Space Explorer Center - MarSEC (Marana di Crespadoro, Italy - B79).
Any inquiry on these observations can be addressed either to Alessandro Marchini (marchini@unisi.it) or to Gaia Verna (gaia.verna@unisi.it). We will continue monitoring the source in the following nights. Multi-wavelength follow-up is strongly 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 , the page of the
Montarrenti Observatory and the page of the MarSEC Observatory.
Astronomical Observatory of the University of Siena - Official Webpage
