Brightening of FSRQ 3C 454.3 with an intense optical micro-variability.
ATel #9723; Navpreet Kaur(PRL/IITGn, India), KS Baliyan(PRL), CM Mukesh(PRL), S Ganesh(PRL), A Janaka(PRL)
on 7 Nov 2016; 11:57 UT
Credential Certification: Kiran S Baliyan (baliyan@prl.res.in)
Subjects: Optical, AGN, Black Hole, Blazar, Quasar, Variables
On the behalf of blazar monitoring group at Mt Abu InfraRed Observatory operated by the Physical Research Laboratory, India, we report detection of micro-variability in FSRQ 3C 454.3 on November 03, 2016 during which it decays by 0.1 mag in R band. The source, however, brightened up with a magnitude of R = 15.34 as compared to the publicly available data from Steward Observatory, Arizona showing R = 15.67 mag on September 26, 2016.
The source 3?C ?454.3 is a very active blazar which has shown several flaring episodes in the past. During June, 2016 an enhanced activity in optical and gamma-rays was seen when the source gradually brightened from R = 15.817 to 14.958 with an increase in polarization from 2.2% to 13.0% during June 10-13, 2016 (Atel #9150). AGILE and Fermi also confirmed its enhanced activity in gamma-rays (Atel #9157, #9176, #9190). While the source was continuously brightening up in optical (R = 15.83 to 13.74), a strong micro-variability was also seen by Balonek et al. (Atel #9178) in about 2.4 hrs. Later it started fading, showing a magnitude of R = 14.6 on June 25, 2016 (ATel #9192).
On November 03, 2016 (MJD 57695) we observed the source in BVRI optical bands, taking 4-images in each band. We also monitored the source for about 20 minutes in R-band during which 3C454.3 exhibited an intense micro-variability with a gradual decay by 0.1 mag. The daily averaged magnitudes obtained on November 03, 2016 (MJD 57695) are B = 16.282 (0.030), V = 15.726 (0.022), R = 15.343 (0.028), I = 14.679 ( 0.018).
Since the onset of its flaring activity in June, 2016, the source faded by more than two magnitudes, i.e., from R = 13.6 on June 23 to 15.67 mag on September 26, 2016 (Steward Observatory). It then started brightening up again reaching R = 15.34 on November 03, 2016.
Intense variability during the low and high flux states is common in such sources. It would be interesting to trace the intra-night variations in its brightening/fading phases. We, therefore, suggest multi-wavelength observations for this source.
