Optical flare observed in the candidate gamma-ray FSRQ J1153-1105
ATel #12328; Tapio Pursimo (NOT), Anlaug A. Djupvik (NOT), and Roopesh Ojha (NASA/GSFC/UMBC)
on 25 Dec 2018; 01:37 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Optical, Gamma Ray, >GeV, AGN, Blazar, Quasar
We report optical photometry of the flat spectrum radio quasar J1153-1105, obtained with the 2.56m Nordic Optical Telescope in La Palma, to look for any enhanced optical activity associated with a recent flare in the daily averaged gamma-ray flux seen in Fermi J1153-1124 (ATel#12206, ATel#12208).
These NOT observations were made using the ALFOSC (Alhambra Faint Object Spectrograph and Camera) instrument at the epoch 2018-12-09T07:04. Standard IRAF data reduction (de-biasing + flat field correction with twilight flats) was carried out and differential photometry was performed. The brightness was calibrated against 17
SDSS field stars near the target. The std-dev of the zero point was 0.03 mag.
We find that PKS J1153-1105 had an SDSS r-magnitude = 18.82 +- 0.03 (AB-system). This result suggests that there is significant enhancement in its optical magnitude. An historic value of this object's r-magnitude from PanSTARRS at mean epoch 2013-02-24 is 19.3 (Chambers et al. 2016, arXiv:1612.05560).
This brightening supports the identification of Fermi J1153-1124 with PKS J1153-1105.
We encourage further multi-wavelength coverage. We will continue to monitor this source and report future developments using this and other platforms.
