Optical Flares in Blazars 1156+295, 1308+326 and 1749+096
ATel #14727; John J. Slater, Riley M. Corcoran, Warner S. Neal, Thomas J. Balonek (Colgate Univ., Hamilton, NY USA)
on 18 Jun 2021; 13:16 UT
Credential Certification: Thomas J. Balonek (tbalonek@colgate.edu)
Subjects: Optical, Blazar, Quasar
We report observations of rapid optical (R filter) flares of up to 2 magnitudes in three blazars - 1156+295 (Ton 0599, 4C +29.45); 1308+326 (OP +313, AU CVn); and 1749+096 (OT +081, 4C +09.57). Each object has reached an optical brightness within 0.75 magnitude (1156+295), 0.5 magnitude (1308+326), or 1.0 magnitude (1749+096) of their peak brightness as seen during the past three decades in the quasar optical variability monitoring program at Colgate University.
Blazar 1156+295 (z=0.724) has been undergoing a year-long period of enhanced optical activity, beginning with a brightening of 2.6 magnitude between late-October 2020 and mid-February 2021 (ATel #14391). Rapid brightening of more than 0.5 magnitude has been observed in one day (ATel #14391, ATel #14547). The current optical flare of at least 1.6 magnitude began less than two-weeks ago (ATel #14696), and is likely associated with the enhanced gamma-ray activity reported by the Fermi Large Array Telescope (LAT) Collaboration (ATel #14722).
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.
2021-06-11.13 UT (JD 2,459,376.63) R = 14.60 ± 0.04
2021-06-17.13 UT (JD 2,459,382.63) R = 13.70 ± 0.02
2021-06-17.18 UT (JD 2,459,382.68) R = 13.70 ± 0.05
2021-06-18.10 UT (JD 2,459,383.60) R = 13.78 ± 0.02
2021-06-18.18 UT (JD 2,459,383.68) R = 13.83 ± 0.04
Blazar 1308+326 (z=0.997) has been undergoing a multi-year optical outburst since 2018 with enhanced activity in 2019 (ATel #12898), exhibiting multiple short timescale flares. It exhibited flaring activity at gamma-ray wavelengths in mid-February 2021 (ATel #14404). We report a brightening of 1.4 magnitudes to R ~ 15.5 in eight days, a level about half-a-magnitude fainter than the multiple outburst peaks in 2019 and 2020.
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.
2021-06-10.29 UT (JD 2,459,375.79) R = 16.85 ± 0.11
2021-06-11.09 UT (JD 2,459,376.59) R = 16.30 ± 0.05
2021-06-13.10 UT (JD 2,459,378.60) R = 16.23 ± 0.05
2021-06-17.10 UT (JD 2,459,382.60) R = 15.71 ± 0.03
2021-06-17.22 UT (JD 2,459,382.72) R = 15.66 ± 0.03
2021-06-18.12 UT (JD 2,459,383.62) R = 15.47 ± 0.02
Our observations of blazar 1749+096 (z=0.322) indicate a brightening of 2 magnitudes since early-May 2021 (R ~ 17.8) when it was near its historic minimum (see the light curve by the SPbSU Virtual Observatory, https://vo.astro.spbu.ru/sites/default/files/optic/ot081R.png).
Our preliminary photometric results for 1749+096, using comparison star C4 (R = 13.91) of Smith et al (1988, PASP, 110, 1164), are presented below.
2021-06-11.21 UT (JD 2,459,376.71) R = 15.76 ± 0.04
2021-06-13.27 UT (JD 2,459,378.77) R = 16.21 ± 0.04
2021-06-17.26 UT (JD 2,459,382.76) R = 15.79 ± 0.03
2021-06-18.20 UT (JD 2,459,383.70) R = 15.82 ± 0.03
The average brightness is calculated from several 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 NASA / New York Space Grant and the Colgate University Justus '43 and Jayne Schlichting Student Research Fund.
We encourage multi-wavelength observations of these outbursts.
