Ongoing rotation of the optical polarization angle for the blazar GB6J1037+5711

ATel #6261; I. Myserlis (MPIfR, Germany), I. Liodakis, G. Panopoulou (Univ. of Crete, Greece) on behalf of the RoboPol collaboration
on 24 Jun 2014; 00:47 UT
Credential Certification: Dmitriy Blinov (blinov@physics.uoc.gr)

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We report about the ongoing rotation of the optical polarization angle (R-band) seen in the monitored blazar GB6J1037+5711 (J1037+5711, RA= 10:37:44.30, DEC=+57:11:55.6 in J2000) as recorded within the framework of the RoboPol program. The optical polarization angle has been rotating from the start of the current observing season, April 30, 2014 and the magnitude of the rotation so far is 248 degrees, clockwise (from 39 to -209 degrees). We cannot pin-point the start of the rotation to a better detail. The last observation of the previous season was conducted on November 9, 2013 and the optical polarization angle was 99.9 degrees. During the reported, slow rotation (~5 degrees per day), the polarization degree in the R-band has been fluctuating between a maximum of 5.5+/-2.8% and a minimum of 0.8+/-0.5%. Relative photometry based on USNO-B1.0 Catalog magnitudes (Monet et al., 2003, AJ, 125, 984-993) shows that the blazar is stable at optical wavelengths (R-band) for the same period with a mean magnitude of 15.3. Preliminary analysis of the publicly available Fermi LAT data for the source 2FGL J1037.6+5712, which is positionally consistent with the blazar, shows no increase in the gamma-ray emission. Averaged gamma-ray photon flux (E>100MeV) during the rotation period (2.2+/-0.5)x10^-8 photons cm^-2 s^-1 is consistent with the average flux reported in 2FGL catalog (2.2+/-0.08)x10^-8 photons cm^-2 s^-1.
Multifrequency observations of the blazar are strongly encouraged.

The RoboPol program aims at understanding the AGN physics through optical linear polarization monitoring of a large sample of gamma-ray loud blazars as well as a comparison sample of gamma-ray quiet ones. It utilizes a novel-design 4-channel optical polarimeter mounted at the 1.3-m Skinakas telescope in Crete. It is a collaboration between the University of Crete (Greece), Max-Planck-Institut fur Radioastronomie (Germany), California Institute of Technology (USA), Nicolaus Copernicus University (Poland) and the Inter-University Centre for Astronomy and Astrophysics, (India).