Polarization and photometric observations of the gamma-ray blazar PG 1553+113

Authors :: Andruchow, I.
Combi, J. A.
Muñoz-Arjonilla, A. J.
Romero, G. E.
Cellone, S. A.
Martí, J.
Publication Year :: 2011
Abstract: We present the results of an observational photo-polarimetry campaign of the blazar PG 1553+113 at optical wavelengths. The blazar was recently detected at very high energies (> 100 GeV) by the H.E.S.S and MAGIC gamma-ray Cherenkov telescopes. Our high-temporal resolution data show significant variations in the linear polarization percentage and position angle at inter-night time-scales, while at shorter (intra-night) time-scales both parameters varied less significantly, if at all. Changes in the polarization angle seem to be common in gamma-ray emitting blazars. Simultaneous differential photometry (through the B and R bands) shows no significant variability in the total optical flux. We provide B and R magnitudes, along with a finding chart, for a set of field stars suitable for differential photometry.<br />Comment: 4 pages, 3 figures. To be published by Astronomy and Astrophysics