Investigating the evolution of PKS B1144-379: Comparison of VLBI and scintillation techniques

Abstract

We have investigated the evolution of the BL Lac object PKS B1144-379 using the University of Tasmania Ceduna 30-m radio telescope at a frequency of 6.7 GHz and very long baseline interferometry (VLBI) data at 8.6 GHz. Variability time-scales associated with two flares detected in 2005 November and 2008 August were derived from long-term variations in total flux density monitored by Ceduna between 2003 and 2011. A kinematic study of the parsec-scale jet of PKS B1144-379 was performed using VLBI data obtained between 1997 and 2018. Quasi-periodic flarings with a period of ∼3-4 yr were observed. Over the 20-yr interval, the average jet position angle was found to be ∼150°.