SRDP

Science Ready Data Products

What is the Science Ready Data Products (SRDP) Initiative?

The goal of the SRDP Initiative is to improve the user experience for radio interferometry data from the VLA and ALMA by providing users with science quality data as well as providing tools for data processing and discovery through an updated archive interface.

The products and capabilities provided by SRDP will enable VLA and ALMA users to primarily focus on their science rather than the details of data reduction.  This will help broaden the NRAO user community by reducing barriers (both expertise and computing infrastructure) to the use of radio interferometry data.

Archival research will be facilitated with an interactive archive to enable data discovery without large downloads.

Features

SRDP features will be released approximately yearly, with subsequent releases adding new features and enhancing existing features. SRDP began pilot operations in June 2019  with the following features:

  • Quality Assured calibration for selected VLA projects
    • To qualify for SRDP calibration the following conditions must be met:
      • Observations should be in C, X, Ku, K, Ka, or Q bands (may include multi-band datasets that do not use any other bands).
      • The SRDP pipeline is optimized for continuum science. Observations should have wide (~1 GHz or wider) bandwidths (i.e. be focussed on continuum science, not on narrow spectral lines).
      • Scheduling blocks need to follow the recommended calibration strategy for the band, with standard intents.
      • Phase calibrators should not be significantly resolved (<5%).
      • Observations should use one of the two standard flux calibrators that has not varied recently (3C286 or 3C147). Observations using 3C48 or 3C138 as calibrators are currently excluded.
    • Polarimetric (cross-hand phase and leakage) calibration is not currently included, though Stokes I SRDP calibration will be performed on polarimetric datasets that satisfy the conditions above.
  • ALMA Calibrated Measurement set download
    • Cycle 5 data and beyond
    • only available for data calibrated by pipeline (no manual reductions)
  • VLA Calibrated Measurement set download
    • only available for data for which calibration pipeline run was successful
  • Updated NRAO archive interface (data.nrao.edu)
  • ALMA User-Defined Imaging
    • Generate datacube with a custom spectral axis from a pipeline-reduced dataset
    • User-defined spectral width of cube
    • Velocity or frequency definitions supported
    • Channel averaging
    • Angular resolution modification (higher or lower resolution). This is limited by what data will allow, one may not exactly get their requested resolution.
    • Continuum (aggregate and per-spectral window) produced as ancillary product
    • Quality assurance to check that the datacube is of good quality, with no obvious artifacts, and has the RMS and beam size expected given the data it was constructed from. (Note this is distinct from the ALMA QA process, and is designed only to catch problems with the images.)

Pilot operations will continue while we assess the performance of the SRDP system and optimize operational processes. Full Wave-I operations are expected to be available to the entire community in the Spring of 2020.

Pre-requisites:

The SRDP system features are publicly available; any user from any country or ALMA region may utilize the SRDP system. Users are required to have an NRAO account at in order to use many of the SRDP features. To access ALMA data, users must link their NRAO user account to their ALMA account. They may do this by visiting their ALMA science portal, logging-in, editing their profile, and linking to their NRAO account under the tab 'Account linking.'

Help with SRDP products:

Please visit the NRAO helpdesk and submit a ticket under the ‘Data Products’ Topic.