Candidate VettingΒΆ

GWCelery orchestrates and supervises performing basic data quality and detector state checks, grouping of events from individual pipelines into superevents, initiating automated sky localization and parameter estimation, inferring classification and source properties, and sending alerts.

A Data Quality Report is prepared that consists of a semi-automated detector characterization and data quality investigation for each significant event. (See Alert Threshold for an explanation of what constitutes a significant event.) It provides a variety of metrics based on auxiliary instrumental and environmental sensors that are used by the rapid response team (RRT) in order to make a decision of whether to confirm or retract a candidate.

All significant candidates are handled by non-expert RRT members at first. Expert members of the team will only be convened as necessity arises.

However, when the candidate satisfies at least one of the following conditions, all RRT members including the experts will start investigating as soon as the public alert is issued to provide a higher level of scrutiny.

  1. Coincidence with non-GW events. (See Coincident with External Trigger Search.)

  2. A significant unmodeled burst trigger has the lowest false alarm rate in a superevent. (See Unmodeled Search.)

  3. A SSM trigger is preferred.

  4. A CBC trigger is preferred AND has less than 0.5 probability of being terrestrial AND satisfies at least one of the following conditions.

    • Probability that the candidate is BNS is larger than 0.1.

    • Probability that the candidate is NSBH is larger than 0.1.

    • Probability that some neutron star material remains outside the final black hole remnant is larger than 0.1.

    • 90% credible region in the sky localization is smaller than 100 square degrees.

If one of these conditions is met at the time of the first or the second Preliminary Notice, the candidate will be automatically labeled HIGH_PROFILE on GraceDB. (See GraceDB Reference Manual.)

Once applied, the label will not be removed regardless of the later findings, even if the candidate is retracted.

In rare cases, RRT might manually apply HIGH_PROFILE label to superevents for reasons other than the conditions listed above. In such cases, a brief explanation will be given in the Circular.