MPIfR: Eduardo Ros

A Quasi-Periodic Modulation of the Radio Light Curve of the Blazar PKS B0048-097,
M. Kadler, P. A. Hughes, E. Ros, M. F. Aller, & H. D. Aller
Astronomy & Astrophysics, submitted
- Abstract In this letter we present the results of a Morlet wavelet analysis of the radio light curve of the BL Lac Object PKS B0048-097 from the University of Michigan Radio Astronomy Observatory monitoring program at 8 GHz during twenty-five years, from 1979 to 2004. The results show a remarkable periodicity of 450-470 days in the early 1980s that changed to a 585 days periodicity in the late 1980s to early 1990s. Very-long-baseline interferometry imaging at 15 GHz shows dramatic structural changes in the usually unresolved source between two epochs, 1995.57 and 2002.38. The pronounced northward directed jet seen in the 2002 image dirs by more than 90 in direction from the source structure found in earlier epochs. These findings make PKS B0048-097 a primary target for multiwavelength observations and intensive radio monitoring to decipher the BL Lac phenomenon.