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Knowledgebase: Archive & Data Retrieval
What are the criteria for data to be considered successful and delivered?
Posted by John Hibbard, Last modified by Rein Warmels on 16 March 2017 01:38 PM

ALMA Observations are subject to "best efforts", meaning that the observatory will attempt to meet the sensitivity and resolution stated by Primary Investigators (PIs) in their Science Goals. Each project component ("Schedule Block" or SB) is scheduled for the number of executions that are expected to reach these goals (based on nominal Array performance values), but the resulting products may ultimately fall short of the requested goals, due to limits imposed by the available configurations or system performance. Given these considerations, the following tolerances on the PI-requested parameters have been adopted for Cycle 1 and 2 data when performing Quality Assurance on the data products (QA2; see the ALMA Technical Handbook). 

If the products meet the following criterion, they are declared QA2 Pass and delivered to the PI:

  • Sensitivity less than or equal to 1.1× PI request for Band 3,4,6 data
  • Sensitivity less than or equal to 1.15× PI request for Band 7,8 data
  • Sensitivity less than or equal to 1.2× PI request for Band 9 data
  • Synthesized Beam area less than or equal to 1.2× PI request

If the products do not meet the above criterion but fit within less stringent criterion listed below and are judged to meet the PIs science goals stated in the proposal (by virtue of signal-to-noise ratio or other properties), they are declared QA2 Pass and delivered to the PI:

  • Sensitivity less than or equal to 1.4× PI request for Band 3,4,6 data
  • Sensitivity less than or equal to 1.5× PI request for Band 7,8 data
  • Sensitivity less than or equal to 1.6× PI request for Band 9 data
  • Synthesized Beam area less than or equal to 1.5× PI request

If the products do not meet the above criterion, they are declared QA2 Fail, are not delivered, and the corresponding SB is set back to Ready so that it is available for future scheduling.

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