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FERMIGDAYS: Help

FERMIGDAYS - Fermi GBM Daily Data


Overview

The Fermi GBM Daily Data database table contains entries for each day for which GBM data has been processed.

The daily data products consist of GBM data that are produced continuously regardless of whether a burst occurred. Thus these products are the count rates from all detectors, the monitoring of the detector calibrations (e.g., the position of the 511 keV line), and the spacecraft position and orientation. The underlying Level 0 data arrive continuously with each Ku band downlink. However, the GBM Instrument Operations Center (GIOC) will form FITS files of the resulting Level 1 data covering an entire calendar day (UTC); these daily files are then sent to the GSSC. Consequently, the data latency is about one day: the first bit from the beginning of a calendar day may arrive a few hours after the day began while the last bit will be processed and added to the data product file a few hours after the day ended. These data products may be sent to the GSSC file by file as they are produced, not necessarily in one package for a given day.

Note that the data may include events from slightly before and slightly after the day official boundaries, which will be reflected in the start and stop times in the table. Consequently, some events may be listed in files for two consecutive days (e.g., at the end of one and the beginning of the next).

Due to the continuous nature of GBM processing, new data files may arrive after the day has been included in Browse and reprocessed version may also arrive at any time. The reprocessed data will have the version number incremented (see file name conventions below). Browse will automatically download the latest versions of the data files.


Bulletin

The FERMIGDAYS database table was last updated on 25 February 2009.

Caveats

Please see the warnings on the GBM Caveats page, http://fermi.gsfc.nasa.gov/ssc/data/analysis/software/caveats.html

References

See the Fermi Science Data Products Interface Control Document (GLAST-GS-ICD-0006; http://fermi.gsfc.nasa.gov/ssc/dev/current_documents/Science_DP_ICD.doc)

Provenance

This database table was created and updated by the HEASARC based on information supplied by the GLAST Project.

Parameters

Day_Number
The MJD (Modified Julian Date) day number for each day for which GBM data has been processed.

Time
The start time of the data for the specified day number.

End_Time
The stop time of the data for the specified day number.

Day_ID
The unique day identification in YYYYMMDD format.


Contact Person

Questions regarding the FERMIGDAYS database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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