Processing Version 220.127.116.11
Last updated on 2006 September 4 (originally posted on 2006 June 20)
This is a minor update from version 18.104.22.168. This update does not affect the products. Users do not have to reprocess data.
- XIS files:
- Timing mode data are not processed.
- Dead time is not calculated when the burst mode option is used.
- Some of the events might have invalid PI values (PI=4095), when the burst and window options are combined. These events are effectively removed from the subsequent analysis, resulting in a slight reduction in normalization. See Suzaku Memo 2006-2 for details.
- Details of the limitations associated in the data processing are summarized in Suzaku Memo 2006-16.
- The XIS team is preparing background database and tools to be used by Guest Observers for extended source analysis.
- HXD files:
- GSO data in this release still have large calibration uncertainties. It cannot be used for scientific purpose.
- HXD background estimator is currently being tested by the instrument teams.
- Background event files will be provided by the team. At present the PIN background subtraction is accurate at the 5% level, the GSO background is presently under study and is less reliable.
- Dead-time correction has not been applied to the data, and is of order 5% for background-dominated sources.
- Common issues:
- There is a time-dependent misalignment of 30-60 arcsec, which is synchronized with the orbital period of the satellite (96 min). This is not incorporated to calculate X/Y in this version. A correction tool is under development.
- Spectral Analyis:
- Response generators are not included in this release; standard RMF and ARF files can be obtained from CALDB page. The ARF files are limited to point source files for standard pointing positions.
- In HXD nominal position the response files for XIS0 and XIS1 are not reliable and are offset from XIS2 and 3 and the PIN. Care should be taken in using these data.
- These responses do not include the XIS contamination, which is time, position, and sensor dependent. Spatial distibution of the contamination will also affect the analysis of diffuse sources. Detailed documentation is under preparation.
- The calibraton of the energy scale is underway. XIS gain is accurate to max(15 eV, 0.5%).
- Effect of the radiation damage is under study now. In addition, inprecise correction for spatially dependent charge transfer inefficienty (CTI) results in line broadening of order 50 eV (in sigma) at Fe K, and a degradation of quantum detection efficiency of about 5%.
- XIS calibration accuracy becomes worse in window mode or in 2x2 mode.
- Artificial structure is present in the XIS spectrum in 500-504 ch, which should be discarded from the analysis.
- Local structures may be present in the XIS spectrum with a level of +-15% in 2-8 keV.
- HXD/PIN response is currently guaranteed in the 12-40 keV range.
- Users should allow 5% uncertainties in HXD/PIN-XIS cross-normalization. A detailed document is under preparation.
- Timing Analysis:
- XIS event times are quantized to 8s (see above). Their absolute accuracy is not calibrated yet.
- HXD event times have 61 microsec resolution. Absolute timing accuracy is not yet calibrated to this resolution.
- Barycentric correction software is not included, but it is under development
- Imaging Analysis:
- Exposure map software is not yet included.
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