The FSRQ B2 1308+326: reaching the new absolute maximum and still brightening
ATel #15459; V. V. Vlasyuk, O. I. Spiridonova, O. A.Maslennikova (Special Astrophysical Observatory of the Rus. Ac. Sci.)
on 23 Jun 2022; 10:38 UT
Credential Certification: Alexander Moskvitin (mosk@sao.ru)
Subjects: Optical, Quasar
The flat spectrum radio quasar B2 1308+326 is observing by SAO RAS team on a regular basis in search of possible intra-day variations and correlation between optical and radio activity events. Since 2021 we have started regular optical observations with two telescopes: 1-m reflector Zeiss-1000 and 0.5-m RC500 reflector (JSC ASTROSIB, Russia).
As it was shown in previous studies (ATel #12898, ATel #14727, ATel #15334, ATel #15399) FSRQ B2 1308+326 undegone some phases of brightness flares since 2018. It's brightness maximum reached as high as R~14.7 mag at May, 6th. Current stage of unprecedented flares has begun in June --- it's brightness reached R = 14.60 +/- 0.02 at June, 19.23UT (ATel #15441) and R = 14.06 +/- 0.05 at June, 20 23.7 UT (ATel #15447), respectively.
Our data, taken with 1-m Zeiss-1000 reflector at nights June, 20/21, 21/22 and 22/23, gave next mean values (data variation includes some trends):
| MJD | Rmag | Data Variation,mags | Error,mags |
| 59750.77 | 14.17 | 0.01 | 0.01 |
| 59751.85 | 14.04 | 0.02 | 0.005 |
| 59752.82 | 13.86 | 0.03 | 0.005 |
Last night data, taken within 2.5 hours, demonstrated significant growth between R=13.87 and R=13.85, so object is "still rising", as was noted in (ATel #
15447). No any minute variations of flux were detected at level 0.01 mag.
As a comparison star the object F from Smith et al (1985, AJ, 90, 1184) was used. Using by our own calibrations we attributed it's magnitude as R=14.00 instead of Smith's value R=13.88.
More accurate reduction is necessary. We strongly encourage further multi-wavelength coverage.
