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Suzaku Guest Observer Facility

Two Important Calibration Updates

June 18, 2008


1. Error in June 2 release of CALDB

The XIS team has discovered a bug in the XIS quantum efficiency (QE) files (ae_xi[0-3]_quanteff_20080504.fits) released in the recent CALDB update made on June 2, 2008.

Specifically, the team has found that the latest QE files are not correct below 2 keV, with errors as large as 20%. RMF files generated by xisrmfgen with the QE files are thus not correct. Related problems also exist in XIS "teldef" and XRT "reflect" and "mirror" files, which affect the arf files as well.

As of 2008 June 18, we have re-ingested the CALDB files to point to earlier versions of these calibration files. The XIS0 contamination file originally released on June 2 is still valid, and it is flagged as such.

Users who have downloaded the June 2 version of Suzaku CALDB, or have used the Suzaku CALDB since June 2 to generate response files, are advised to take corrective acction of re-downloading the corrected CALDB and/or re-generating the responses.

We apologize for the inconvenience.


2. Release of "tuned" background model for HXD/PIN

The HXD team has released a new ("tuned") non X-ray background (NXB) model for the PIN. Since this model has a significant lower systematic uncertainties (1.3%) compred to the previous (now called "quick") model, users are advised to use the tuned NXB model whenever possible.

Because this method needs one month worths of calibrated GSO event files, it takes 1-2 months after the finish of pipeline processing for the HXD team to deliver the tuned NXB model. The HXD team will therefore continue to produce the quick NXB model files as well, which should now be used for quick-look purposes only, before the tuned NXB model is avalable.

For more, see the PIN background page.


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This file was last modified on Tuesday, 17-Jun-2008 19:52:38 EDT

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