A.1 VLARUN

The user should read AIPS Memo 112, “Capabilities of the VLA pipeline in AIPS,” by Lorant O. Sjouwerman dated March 19, 2007. This memo goes into details and advice that are beyond the scope of this appendix. The memo may be obtained from the AIPS web set http://www.aips.nrao.edu/.

To use the pipeline, you must first load the VLA Archive or other multi-source visibility data into AIPS; see O.1.1. To acquire the pipeline, including all procedures and special adverbs, enter

> RUN VLARUN  C R

to define the procedures and adverbs

Do this only once. The procedures will be remembered in your LASTEXITSAVE/GET file.

The pipeline has three stages: (1) calibration and editing, (2) basic imaging, and (3) self-calibration. Study the recommendations and other advice in EXPLAIN VLARUN  C R. Note that VLARUN can also handle spectral-line data. Then, the inputs for the calibration stage include

> TASK VLARUN’ ; INP  C R

to review the inputs needed.

> WORKDISK n  C R

to specify the disk containing the uv data.

> CATNUM catn  C R

to specify the catalog number of the uv data; INNAME et al. may also be used.

> FASTSW 1  C R

to correct source name peculiarities induced by fast-switching observations.

> AUTOFLAG 2  C R

to use FLAGR on all data and QUACK on all but high frequency data sets

> PHAINT 1 ; AMPINT 5  C R

to set the phase calibration interval to 1 minute and the amplitude calibration interval to 5 minutes.

> DOMODEL 1  C R

to use standard flux calibrator models where available.

> NOPAUSE -1  C R

to have the pipeline pause after GETJY to allow you to evaluate whether it is okay to proceed.

> AUTOPLOT -1  C R

to make no diagnostic plot files.

> DOIMAGES -1  C R

to do calibration and editing only.

> INP ; TPUT  C R

to double check the inputs and save them.

> VLARUN  C R

to calibrate and edit your data.

The pipeline can do imaging and even self-calibration, although the latter is not for the faint at heart. To include this in your pipeline run, enter

> DOIMAGES 1  C R

to request imaging.

> ARRYSIZE 0  C R

to let the procedure find the array dimensions.

> IMSIZE -1  C R

to image the target source over the full primary beam, with smaller areas for calibrators.

> NITER nit ; CUTOFF f  C R

to set the number of iterations nit and Clean flux limit f. NITER must be > 0 for the image to be Cleaned. Use conservative values to begin with and higher limits in subsequent runs.

> ALLIMG 1  C R

to make images of calibrators as well as target sources.

> SLFCAL 0  C R

to avoid self-calibration initially.

> INP ; TPUT  C R

to double check the inputs and save them.

> VLARUN  C R

to calibrate, edit, and image your data.

In the first run of VLARUN, it is recommended to avoid self-calibration although the making of images will help you evaluate the quality of the auto-editing. If your data are not “perfect” (i.e., good enough), then consider one or more of the interactive editing tasks such as TVFLG (O.1.6), SPFLG (10.2.2), EDITA (4.3.11), and EDITR (5.5.2) along with the advice given on editing in 4.3.5, 4.3.13, O.1.5, and 5.5. Then

> TGET VLARUN  C R

to restore the inputs.

> AUTOFLAG -1  C R

to do no more automatic flagging.

Consider raising NITER and/or lowering CUTOFF in this second pass, plus

> SLFCAL snit  C R

to also do self-calibration with interactivity on the TV (snit > 0) or in a batch-like process (snit < 0) for |snit| self-cal iterations.

> INP ; TPUT  C R

to double check the inputs and save them.

> VLARUN  C R

to calibrate, edit, and image your data.

Repeat as needed. Note that VLARUN has been used on many of the data sets in the VLA archive, with the results archived at http://archive.nrao.edu/. These results include both images and calibrated uv data sets.