Optical activity of the flaring gamma-ray FSRQ NRAO 676

ATel #4254; Tapio Pursimo (Nordic Optical Telescope), Roopesh Ojha (NASA/GSFC), Jens Jessen-Hansen (Nordic Optical Telescope), and Michael Dutka (Catholic Uni.)
on 12 Jul 2012; 16:11 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)

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We report optical photometry of the high redshift (z=1.899; Sowards-Emmerd et al. 2005, ApJ, 626, 95) flat spectrum radio quasar NRAO 676 (TXS 2159+505) obtained with the 2.56m Nordic Optical Telescope in La Palma. Nearly simultaneous observations were taken with R and i-filters on July 7. The photometry was calibrated against five nearby field stars using GSC2.3 F and N-magnitudes as reference. The results are:
2012 July 7 UT 04:10 R=17.7
2012 July 7 UT 04:12 i=16.9

As a comparison GSC2.3 (Lasker et al. 2008, AJ, 136, 735) reports F=18.90 and N=17.87 (1989.745) and USNO-B R=18.75 and I=17.94 (1980.9), indicating about one magnitude brightening.

These observations were made in response to the dramatic increase in the daily averaged gamma-ray flux seen in the public lightcurve of the Fermi/LAT instrument http://fermi.gsfc.nasa.gov/FTP/glast/data/lat/catalogs/asp/current/lightcurves/NRAO676_86400.png which first reported a detection of gamma-ray activity from this source on Jun 18th, 2012 (ATel#4182).

Given the nature of this object and its continuing gamma-ray activity we encourage further multi-wavelength coverage. We will continue to monitor this source and report future developments using this and other platforms.