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Special Notice #426: Blazar CTA 102 (4C 11.69) in very bright outburst

December 1, 2016: The blazar CTA 102 (4C 11.69) has been in an active state in gamma-ray and optical wavelengths since 2015. During 2016, it has had numerous flaring episodes, particularly since late October. It is presently in an unprecedentedly bright optical state, and showing substantially increased emission in gamma-ray and near-infrared wavelengths.

To quote T. Balonek (Colgate University) et al. (ATel #9808): "The blazar CTA 102 continues its amazing intra-day optical flaring activity during a prolonged outburst, reaching the unparalleled optical brightness of R ~ 11.85 on 2016 November 30 (UT). This is one-and-a-half magnitudes brighter than observed during any outburst prior to 2016 November, more than three-quarters magnitude brighter than the blazar's previous reported brightness record on 2016 November 13 (ATel #9756), and five magnitudes brighter than the blazar's quiescent level (around R ~ 17.0).

"On 2016 November 30 at 3 UT (JD 2457722.63), preliminary reductions show CTA 102 at R ~ 12.05. During the next hour, the blazar brightened by 0.2 magnitudes to R ~ 11.85 at 4 UT (JD 2457722.67)."

Observations in the AAVSO International Database (AID) from later on November 30 (Nov. 30.72487 UT) showed CTA 102 at R = 12.673 +/-0.004, Nov. 30.72400 at B = 13.428 +/-0.008, and Nov. 30.72313 at V = 12.935 +/-0.005 (DUBF, F. Dubois, Zillebeke, Belgium). The most recent observations in the AID show it on 2016 December 1.66869 UT at magnitude V = 12.023 +/-0.020 and on Dec. 1.67044 at R = 11.712 +/-0.073 (WTHB, T. Wikander, Borlange, Sweden).

Observations in all bands are requested; visual observations are welcomed. Changes of a few tenths of a magnitude over a period of a few hours have been observed. Thus, CCD/DSLR observations should be closely spaced.

Coordinates (2000.0): R.A. 22 32 36.41  Dec. +11 43 50.9

Charts: Charts with a comparison star sequence for CTA 102 may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the name CTA 102.

In addition to ATel #9808, information in this Special Notice has been gathered from Astronomer's Telegrams #9676, 9732, 9743, 9756, 9776, 9788, and 9801.

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


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