2.3 Radio Observations

Radio data of PG 1211+143 at C-band (4-8 GHz) and K-band (18-26 GHz) were taken on 2015 June 18 with the `A' configuration of the Karl G. Jansky Very Large Array (VLA) for a total time on source of 7.0 ks at K-band and 3.9 ks at C-band. At K-band we made frequent visits to a bright nearby calibrator, J1215+1654, to ensure good phase calibration, and also used pointing reference mode. The data were reduced in the standard manner for continuum mode using the Common Astronomy Software Applications (CASA) package to produce broad-band images with nominal central frequencies of 6 and 22 GHz, with resolution of respectively 0$\mbox{$.\!\!^{\prime\prime}$}$$24 \times 0$$\mbox{$.\!\!^{\prime\prime}$}$$22$ and 0$\mbox{$.\!\!^{\prime\prime}$}$$065 \times 0$$\mbox{$.\!\!^{\prime\prime}$}$$61$, and rms noise levels of respectively 10 and 6 $\mu$Jy beam$^{-1}$: in addition we split the K-band bandwidth into low and high frequencies to make 20-GHz and 24-GHz images. We also analysed a short archival observation with the un-upgraded VLA , taken on 1993 May 02 in the `B' configuration as part of program AP250, which was reduced in the standard manner using the Astronomical Image Processing System (AIPS).