XIS Responses for Simulations: Cycle 2 Versions

The XIS and XRT team have released a set of response files that are suitable for the preparation of AO-2 proposals.

There are three units of XIS with a frontside illuminated (FI) CCD, and one unit (XIS1) with a backside illuminated (BI) CCD. We provide a RMF and an ARF for the BI CCD and those for FI CCDs separately.

The ARF files include the transmission of the thermal shield, the XRT-I effective area, and the loss of the low-energy efficiency. We prepare three cases as follows; for a point source observed at the XIS nominal position, a point source at the HXD nominal position, and for a circular flat field sky with a 20' radius. The XIS RMF includes the transmission of the optical blocking filter (OBF) and the quantum efficiency of the CCD.

This release consists of the following 8 files.

The degradation of the low-energy efficiency is taken into account in these ARF files. Although the degradation progresses gradually with time, we have applied the loss expected on August 1th, 2007 (2007-08-01T00:00:00) to the ARFs.

For the FI CCDs, please note that we have summed the responses of XIS0, XIS2, and XIS3 into ARFs labeled "3FI."

We also note that the Spaced-row Charge Injection introduces dead areas on the CCDs. The fractions of these dead areas are 5.6% for the FI CCDs and 7.4% for the BI CCD. This correction is not included in the above response files. When estimating the observation time, please consider this effect separately.

For simulation of relatively faint point sources, these responses can be used with the blank sky spectra. For some applications, it may be important to consider the night earth data, containing the particle (but not the cosmic X-ray) background.