The Ginga Archive


photo of Ginga in the clean room The Ginga archive includes High level products, such as lightcurves and spectra in FITS format and accompanying GIF view, and the raw data, which have been reformatted into FITS. The data are all for the Large Proportional Counter (LAC) experiment. No data are available for the All-Sky Monitor or the Gamma-Ray detector.
Different groups have contributed to the final LAC Ginga archive. The University of Leicester generated the LAC source and background spectra and the source lightcurves, while Penn State University (via an ADP grant) provided the LAC raw data and the HEASARC provided the LACDUMP. The Tenma data restoration was included in the same Ginga ADP proposal, as a possible data set to be done after the completion of Ginga if resources allow. However the Tenma attitude information was found to be lost, making this effort not feasible.
Experiment Lightcurves Spectra Raw
Large Area Proportional Counter fits icon gif fits icon gif icon fits icon

There are 5 databases dedicated to Ginga from which data can be retrieved. High level data (spectra and lightcurves) and raw data files are available for retrieval. The Ginga database can be accessed via Browse . Ginga data are located in the GINGA FTP area in the HEASARC archive.

A separate restoration effort of the Ginga data was carried out by ISAS in Japan. During the mission lifetime, at ISAS and other Japanese institutes data and analysis software resided on a FACOM main-frame computer. The restoration effort approch was not to modify the original telemetry data structure when porting the data into FITS. This allows a minimum change to the analysis software which was ported from main-frame computer to a unix enviroment. The archive of these data and software opened in March 2004 and they are available from the Japanese Data ARchive and Transfer System, DARTS, at ISAS.

* High Level Products : Spectra and lightcurves were extracted for the pointed target observations and background observations. To each observation (target or background) several products were extracted. In particular there are spectra and lightcurves for the Mid and Top layer. The lightcurves have been extracted in 4 energy ranges, 2-6, 6-7, 7-17 and 2-17 keV respectively. These products are in FITS and GIF format. There are also available several plots, in GIF format, showing various correlations of the HK parameters and there are two sets of response matrices for the Top and Mid layers. All of the FITS files were produced at the U. of Leicester in exchange for the ASCA archive. More information on how these products were extracted from the raw data file is available in the document "The Leicester Ginga Databases" (ps version is located in the GINGA FTP area in the HEASARC archive).

* Raw data:
The HEASARC has two sets of unprocessed (raw) data: the LACDUMP and the FRF.

  • LACDUMP The HEASARC restored into FITS the observation logs from the Ginga Large Area Counter Array (LACDUMP). Access to these files is available through the GINGALOG and GINGAMODE databases. A Ginga 'observation' consists of varying numbers of major frames which have lengths of 4, 32, or 128 seconds, depending on the setting of the bitrate. Within each 'observation' several parameters are recorded: the pointing mode, the on-board computer mode (related to the bitrate), transmission, ra, dec, magnetic rigidity, the PI (Payload Instrument) counts, the SUD (Surplus over Upper Discriminator) counts etc. All this information is available in the log file, where parameters were recorded on short time scale (4, 32, or 128 seconds) together with the low count and high counts collected during that time frame when pointing at a particular part of the sky. The LACDUMP has now a FITS version. It has been divided in several FITS files, generated every time one parameter, selected from a subset, changes. For each FITS file there is also an associated GIF file. Using these files it is possible to check for transient sources as in the case of a monitoring instrument. The only difference is that the sky-coverage is neither uniform nor complete.

  • First Reduction Files (FRF) Data received from Ginga were stored in First Reduction Files (FRFs) which mirror the telemetry stream from the satellite. Each FRF file corresponds to a period of time when the satellite was in contact with the ground. Some of the data were telemetered in real time and other data were telemetered from the bubble memory on board. Each FRF file can contain data up to 3 different pointing positions. The raw FITS Ginga data are the FRF files restored in FITS format from their native format (ADP grant, PI Corbet, at Penn State). The FITS files were processed from Penn State on a HEASARC machine and the files directly transferred to the Ginga FTP area at HEASARC. The FITS files are bintable with 5 extensions containing raw counts (science data), raw orbital data, raw operational status data, raw housekeeping data and good time intervals. The layout of the science data extension consists of several columns containing counts, stored as an array per row, and one containing time. The datamode sets the number of channels for the count arrays, how the signal from each counter is summed (number of columns) and the integration time.

    The GINGARAW database was derived using keywords stored in the primary header of the FITS file. Each record corresponds to a different pointing position, therefore it is possible that up to 3 records have associated the same FITS file, but different object name and position.


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