Usage of the predefined Bad Time Intervals

Read this to know how to make proper selection of the science windows that should be used in your analysis.

Different things could happen to the instrument during a particular science window. To inform the user on any unusual things that she should be aware of, the list of time intervals which had some anomalies (bad time intervals) has been created and is kept in the latest version of the
$REP_BASE_PROD/ic/jmxi/lim/jmxi_gnrl_bti*.fits file. (To download the files, the user can follow the instructions given to 'rsync' the entire IC structure, as explained in section 6.1).

For JEM-X the BTI are divided into 2 categories:

• BAD_RESPONSE -– indicates a problem related to the response of the instrument, most typically linked to rapid gain changes following the re-activation of the unit after a long dormant period, or after a solar flare.
• BAD_CONFIGURATION - indicates cases affected by change of configuration, or any other problem.

For the most conservative data analysis use the following value of the (hidden) GTI_BTI_Names parameter:

  GTI_BTI_Names="BAD_CONFIGURATION BAD_RESPONSE"

This is also the default value. In case the user wants to analyse data affected by some BTI, the parameter should be modified accordingly (see section 8.2.5). For instance, to analyze periods affected by a solar flare, use GTI_BTI_Names="BAD_CONFIGURATION".

However, you should always be careful while setting this parameter - BTIs are set by the JEM-X team for specific problematic periods; forcing their usage, the reliability of the results can not be guaranteed, especially for fluxes in BAD_RESPONSE cases.