Optical photometry and polarimetry and infrared photometry of 3C 345 in outburst

Abstract

We present V-band CCD photometry, UBVRI photopolarimetry, and near simultaneous JHK photometry of 3C 345 during a renewed outburst in spring of 1992, which reached maximum at the end of April. The observations also show a large and variable polarization. There are very large variations in the position angle, unlike in previously published photopolarimetry of this object. Both the visible and the infrared magnitudes are amongst the brightest that have ever been measured in this object, whilst the continum spectral energy distribution shows that excess in V which has been observed on some, but not all previous occasions. No convincing evidence is seen of rapid infrared variations on time scales of less than 2 hr