National Radio
Astronomy Observatory

3.5.1.2 Input flag mode ’xml’

The input mode inpmode=’xml’ directs the task to input flag commands from a XML SDM online flagging Flag.xml file. When set this opens the sub-parameters:

This mode will look for a file called Flag.xml inside the MS directory specified under vis. Note that if the data was filled from the SDM using importevla (§ 2.2.2) then the relevant XML file will have been copied to the MS already.

The tbuff sub-parameter sets a padding buffer (in seconds) to the begin and end times of the online flags in the XML file. As in importevla, the online flag time buffer tbuff is specified in seconds, but in fact should be keyed to the intrinsic online integration time to allow for events (like slewing) that occur within an integration period. This is particularly true for JVLA data, where a tbuff value of 0.5× to 1.5× the integration time is needed. For example, if data were taken with 1-second integrations, then at least tbuff=0.5 should be used, likewise tbuff=5 for 10-second integrations. Note: For JVLA data you should use 1.5× (e.g. tbuff=15 for 10-second integrations) for data taken in early 2011 or before due to a timing error. We do not yet know what ALMA data will need for padding (if any).

The ants sub-parameter selects the antennas from which online flags will be selected (default is all antennas). For example, ants=’ea01’ is a valid choice for JVLA data.

The reason sub-parameter selects by the REASON field in the Flag.xml file. The default ’any’ means all commands. Note that reason=’’ would only select flags who have a blank REASON field entry.

More information about CASA may be found at the CASA web page

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