Extreme photopolarimetric behaviour of the blazar AO0235+164

SERGIO A. CELLONE; GUSTAVO E. ROMERO; JORGE A. COMBI; JOSEP MART´

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Blackewll Publishing

Año: 2007 vol. 381 p. 60 - 64

0035-8711

ABSTRACT We present optical photopolarimetric observations with high temporal resolution of the blazar AO0235+164. Our data, the first to test the photopolarimetric behaviour of this object at very short time-scales, show significant micro-variability in total flux, colour index, linear polarization degree and position angle. Strong inter-night variations are also detected for these parameters. Although no correlation between colour index and total flux was found, our data seem to support the general bluer-when-brighter trend already known for this object. The polarization degree, in turn, shows no correlation with total flux, but a clear trend in the sense that colour index is redder (the spectrum is softer) when the measured polarization is higher.