XIS Responses for Simulations: Cycle 4 Versions
The XIS and XRT teams have released a set of response files that are suitable for the preparation of AO-4 proposals.
There are two 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.
- XIS RMF:
Note: In Cycle 4, the Spaced-row Charge Injection (CI) is performed by default. This technique mitigates the charge transfer loss and improves the energy resolution. However, the energy resolution has been slightly degraded with time since the first application of the Spaced-row CI in August 2006. Therefore, we have calculated the energy resolution expected on September 1st, 2009 (2009-09-01T00:00:00) in these RMFs.
- XRT-I/XIS ARF:
- ae_BI_xisnom6_ao4_20080910.arf (for BI unit, i.e. XIS1) and
- ae_2FI_xisnom6_ao4_20080910.arf (for the 2 FI units combined)
- ae_BI_hxdnom6_ao4_20080910.arf (for BI unit, i.e. XIS1) and
- ae_2FI_hxdnom6_ao4_20080910.arf (for the 2 FI units combined)
- ae_BI_uniformf_ao4_20080910.arf (for BI unit, i.e. XIS1) and
- ae_2FI_uniformf_ao4_20080910.arf (for the 2 FI units combined)
- Small versions:
For convenience, we also provide a set of combined (.rsp, or .rmf x .arf)
files that are compressed using variable
energy
and channel
binnings. For many targets, the compression
should speed up simulations without adversely affecting the accuracy.
- ae_BI_xisnom6_ao4.rsp.gz (for BI unit, XIS nominal position)
- ae_BI_hxdnom6_ao4.rsp.gz (for BI unit, HXD nominal position)
- ae_BI_uniformf_ao4.rsp.gz (for BI unit, 20' radius uniform source)
- ae_2FI_xisnom6_ao4.rsp.gz (for 2 FI units, XIS nominal position)
- ae_2FI_hxdnom6_ao4.rsp.gz (for 2 FI units, HXD nominal position)
- ae_2FI_uniformf_ao4.rsp.gz (for 2 FI units, 20' radius uniform source)
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 September 1st, 2009 (2009-09-01T00:00:00) to the ARFs.
For the FI CCDs, please note that we have summed the responses of XIS0 and XIS3 into ARFs labeled "2FI". (Because of the XIS2 anomaly, the XIS2 contribution is not included.)
We also note that the Spaced-row CI introduces dead areas on the CCDs. The fractions of these dead areas are 5.6%. This correction, as well as that of bad columns, is considered in the above response files.
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.
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