ACIS event lists contain a boolean flag column named STATUS that CIAO uses to record various data cleaning criteria that are commonly used to remove events likely to arise from the instrumental background.
Historically, two of those cleaning criteria--``afterglow'' identification and ``5x5 background'' identification--produce false positives for sources with high count rates.
Thus, low-rate sources are optimally extracted by applying these cleaning criteria and high-rate sources are optimally extracted by ignoring these cleaning criteria (Broos et al., 2010).
AE supports the optimal extraction of both groups of sources by applying a STATUS=0 filter to the source and background extractions of low-rate sources, and ignoring the STATUS column for high-rate sources.
To take advantage of this capability, the observer should clean Level 2 event data (§7.3) using only the ``safe'' STATUS bits--those not associated with the ``afterglow'' and ``5x5 background'' criteria.
Event lists supplied to AE must now include the STATUS column, whether you care about AE's conditional STATUS filtering or not.