Optical Flare in the flaring gamma-ray FSRQ B2 1128+38
ATel #13728; Tapio Pursimo (NOT), Joonas Viuho (NOT) and Roopesh Ojha (NASA/GSFC/UMBC)
on 11 May 2020; 14:38 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Optical, Gamma Ray, >GeV, AGN, Blazar, Quasar
We report optical photometry of the FSRQ B2 1128+38,
obtained with the 2.56m Nordic Optical Telescope in La
Palma, to look for any enhanced optical activity associated with its
enhanced gamma-ray emission state (ATel#13670).
These NOT observations were made using the ALFOSC (Alhambra Faint
Object Spectrograph and Camera) instrument. Standard IRAF data
reduction (de-biasing + flat field correction with twilight flats) was
carried out. The magnitude is obtained using SExtractor MAG_AUTO and
the magnitude zero point was calibrated against SDSS field stars near
the target. The std-dev of the zero point was 0.03 mag.
We find that B2 1128+38 had the SDSS magnitudes at epoch 2020-04-28T20:30:
------------------------------------------------
FILTER Magnitude Mag_Error
------------------------------------------------
g 17.583 0.023
r 17.388 0.015
i 17.071 0.011
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This compares to SDSS and PS1 magnitudes at epochs 2003-04-15 and
2012-04-09, respectively:
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FILTER SDSS_mag Mag_Error PS1_mag Mag_Error
-------------------------------------------------------------------------
g 18.804 0.009 18.915 0.017
r 18.745 0.010 18.605 0.052
i 18.448 0.010 18.453 0.034
--------------------------------------------------------------------------
This result suggests that there is significant enhancement in the
optical brightness of the flaring gamma-ray FSRQ B3 1128+385, of about
1.3 magnitude.
We encourage further multi-wavelength coverage. We will continue to
monitor this source and report future developments using this and
other platforms.
