We present sensitive ( \sigma < 10 { ~ { } \upmu Jy } { ~ { } beam } ^ { -1 } ) , radio continuum observations using the Australian telescope compact array ( ATCA ) at frequencies of 6 and 9 GHz towards 4 MYSOs .
From a previous , less sensitive work , these objects are known to harbour ionized jets associated with radio lobes , which result from shock processes .
In comparison with that work , further emission components are detected towards each MYSO .
These include extended , direct , thermal emission from the ionized jet ’ s stream , new radio lobes indicative of shocks close ( < 10 ^ { 5 } { ~ { } au } ) to the MYSO , 3 radio Herbig-Haro objects separated by up to 3.8 { \thinspace pc } from the jet ’ s launching site and an IR-dark source coincident with CH _ { 3 } OH maser emission .
No significant , integrated flux variability is detected towards any jets or shocked lobes , and only one proper motion is observed ( 1806 \pm 596 \hbox { $ { ~ { } { ~ { } km } { ~ { } s } ^ { -1 } } $ } parallel to the jet axis of G310.1420+00.7583A ) .
Evidence for precession is detected in all four MYSOs with precession-periods and angles ranging from 66 - 15480 { ~ { } yr } and 6 - 36 \degr respectively .
Should precession be the result of the influence from a binary companion , we infer orbital radii of 30 - 1800 { ~ { } au } .