VLA interferometry imaging workflow

List of differences compared to the ALMA interferometry imaging workflow (ALMA-Imaging-Workflow.md)

Related recipes and template: procedure_hifv_contimage, procedure_hifv_calimage, template_hifv_contimage Related tickets: PIPE-673

  • hif_checkproductsize

    • task parameter

      • maximsize (defaults to -1 for backward compatibilty, set to 16384 for VLA) Mitigate continum image size by changing pixel per beam (min. 4). If imsize still larger than limit, then truncate image. Mitigation parameters for different targets and bands are independent.

  • hif_makeimlist

    • minimum task parameters:

      • intent (default to ‘TARGET’)

      • spw (defaults to science spws per band)

      • specmode (defaults to ‘cont’, no cube imaging at the moment)

    • create list of imaging targets with these parameters per target set:

      • heuristics instance

      • field

      • spw (for specmode=’cont’ remove spws without data )

      • cell (determine it independently for targets and bands)

      • imsize (determine it independently for targets and bands, PB response of 0.294 for K-band and higher frequencies, 0.016 for Ku band and lower)

      • specmode (‘cont’)

      • nbin (not used)

      • gridder (‘standard’)

      • uvrange (per target and band, omit first 5% of baselines if emission is extended)

  • hif_makeimages

    • set additional parameters via task interface:

      • hm_masking (‘none’)

      • hm_cyclefactor (3)

    • run hif_tclean per imaging target and band

  • hif_tclean

    • pblimit=-0.1 to not clip images

    • determine deconvolver (‘mtmfs’ for ‘cont’)

    • determine nterms (2 if fractional bandwidth > 10% else 1)

    • default to robust = 0.5

    • calculate sensitivity

      • sensitivity calculations is optimized for ALMA, may not be precise for VLA continumm images

    • clean down to nsigma=5.0, threshold is set to 0.0mJy (only nsigma threshold is used)

    • make dirty image

    • calculate dirty cube statistics using annuli (pb range 0.2/0.3)

    • caclulate niter using beam / mask size heuristics and threshold=nsigma*residual_robust_rms, limit values to the [10000,10000000] range

    • calculate clean continuum image statistics using annuli (pb range 0.2/0.3)