Bright Optical Flares in Blazars 1156+295 and 1308+326

ATel #15441; Norah Du, Maddie L. Hulburt, Ha-Eun H. Choi, Riley M. Corcoran, Thomas J. Balonek (Colgate Univ., Hamilton, NY USA)
on 19 Jun 2022; 11:18 UT
Credential Certification: Thomas J. Balonek (tbalonek@colgate.edu)

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We report observations of rapid (one week), bright optical (R filter) flares in two blazars - 1156+295 (Ton 0599, 4C +29.45) and 1308+326 (OP +313, AU CVn), both which have been undergoing multi-year outbursts with frequent flares. 1156+295 brightened by 1.5 magnitudes in one week (including 0.85 magnitudes in two days), reaching R = 13.4 on 2022 June 19 (UT). 1308+326 brightened by nearly three-quarters of a magnitude in one week, reaching R = 14.6 on 2022 June 19 (UT).

Blazar 1156+295 (z=0.724) is in the second year of enhanced optical activity which began in late 2020 (see ATel #14353, #14391, #14547, #14696, #14727, #14775). The object has also exhibited flares in gamma-rays (ATel #14722, #14785, #14897) and mm/sub-mm bands (ATel #14781) during this period. Our preliminary photometric results for 1156+295, using comparison star 13 (R = 14.97) of Smith et al (1985, AJ, 90, 1184), are presented below. (The extended sequence of 36 images on June 19, taken over a two hour interval, showed no significant variations. )

2022-06-12.20 UT (JD 2,459,742.70) R = 14.96 ± 0.05

2022-06-14.12 UT (JD 2,459,744.62) R = 14.77 ± 0.05

2022-06-15.13 UT (JD 2,459,745.63) R = 14.50 ± 0.05

2022-06-17.23 UT (JD 2,459,747.73) R = 14.24 ± 0.10

2022-06-19.17 UT (JD 2,459,749.67) R = 13.39 ± 0.02

Blazar 1308+326 (z=0.996) has exhibited multiple flares since 2018 during its multi-year optical outburst (some which have been reported in ATel #12898, #14727, #15334, #15399). It has also exhibited flaring activity at gamma-ray wavelengths (ATel #14404) and NIR wavelengths (ATel #15428) during this period. Our two sequences of observations of 1308+326 at R = 14.6 on 2022 June 19 (UT) is the brightest we have observed it in our one-third-century quasar optical variability monitoring program at Colgate University. Our preliminary photometric results for 1308+326, using comparison star C (R = 13.28) of Smith et al (1985, AJ, 90, 1184), are presented below.

2022-06-01.09 UT (JD 2,459,731.59) R = 15.09 ± 0.03

2022-06-04.18 UT (JD 2,459,734.68) R = 15.35 ± 0.03

2022-06-05.17 UT (JD 2,459,735.67) R = 15.32 ± 0.03

2022-06-10.23 UT (JD 2,459,740.73) R = 15.07 ± 0.03

2022-06-11.28 UT (JD 2,459,741.78) R = 15.16 ± 0.05

2022-06-12.23 UT (JD 2,459,742.73) R = 15.33 ± 0.05

2022-06-14.15 UT (JD 2,459,744.65) R = 15.22 ± 0.03

2022-06-15.13 UT (JD 2,459,745.63) R = 15.03 ± 0.03

2022-06-17.27 UT (JD 2,459,747.77) R = 14.80 ± 0.04

2022-06-19.10 UT (JD 2,459,749.60) R = 14.60 ± 0.02

2022-06-19.23 UT (JD 2,459,749.73) R = 14.60 ± 0.02

The average brightness is calculated from typically one dozen two-minute images taken in a sequence lasting about half-an-hour.

Observations were obtained with the Colgate University Foggy Bottom Observatory (Hamilton, NY USA) 0.4-m Ferson telescope equipped with an FLI PL1001 CCD camera. Student research participation at Colgate University is supported by the Colgate University Division of Natural Science and Mathematics, and the NASA / New York Space Grant.

We encourage multi-wavelength observations of these outbursts.