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Increased activity of the blazar S5 1044+71 with ongoing rotation of optical polarization angle

ATel #5512; D. Blinov (Univ. of Crete, Greece and St. Petersburg Univ., Russia), A. Kougentakis (FORTH, Greece) on behalf of RoboPol collaboration.
on 25 Oct 2013; 16:49 UT
Credential Certification: Dmitriy Blinov (dmitriy.blinov@gmail.com)

Subjects: Optical, Gamma Ray, AGN, Black Hole, Blazar

Referred to by ATel #: 9928

We perform R-band photometric and polarimetric monitoring of the blazar S5 1044+71 (2FGL J1048.3+7144) as part of the RoboPol program. Preliminary relative photometry based on PTF catalog magnitudes (Ofek et al., 2012, PASP, 124, 854) shows that the blazar is in a flaring state at optical wavelengths. Its R-band magnitude is observed to be R=16.0 on 25 Oct, 2013, substantially brighter than R=17.49 reported by (Healey et al., 2008, ApJS, 175, 97) and at the previous period of availability of this object R=17.4 on 13 Aug, 2013. We are also observing a smooth rotation of optical polarization angle in the clockwise direction at rate of about 15 degrees per day coincident with rise of polarization degree reaching P=27.2 % on 25 Oct, 2013. Optical activity is accompanied by increased flux and variability at gamma-ray energies as measured by the Fermi LAT. Daily averaged gamma-ray flux reached 5 x 10^-7 ph cm^-2 s^-1 (E>100 MeV) on Oct 24, which is comparable to a previously reported flare of this object in April 2013 (ATEL #4941).

RoboPol is a collaboration of Caltech USA, Univ. of Crete/FORTH Greece, MPIfR Germany, IUCAA India and Nicolaus Copernicus Univ. Poland.