Calibration status and caveats
- Energy band: hard band, HEASOFT ver: 6.2 (xissim & xissimarfgen ver 2006-11-26)
- Flux and photon index (Ref. Suzaku memo 2006-34 )
The current uncertainty of the effective area of the XRT-XIS system is attributed to a calibrational error of the XRT. Based on the Crab observations in 2005, the on-axis effective area in the 2-10 keV band is well calibrated and accurate to about 2%. Table 1 lists flux and photon index of the Crab spectra, obtained from the power-law model fitting. Their uncertainties in the third and fifth columns of the table are derived by referring to the spectral parameters published by Toor & Seward (1974). On the other hand, the effective area below 1 keV is dependent on thickness of contaminating material on the surface of the XIS sensors and thus considered to show larger uncertainty. At energies < 2keV and >8 keV, the effective area is being calibrated.
Table 1: Power-law model parameters of the Crab spectra taken on 2005-Sep
Sensor Flux Flux uncertainty Photon index Photon index uncertainty XIS nominal positionXIS0 2.15 3% 2.13+-0.02 1% XIS1 2.14 2% 2.07+-0.02 -1% XIS2 2.19 5% 2.09+-0.02 -1% XIS3 2.13 2% 2.07+-0.02 -1% HXD nominal positionXIS0 1.97 -6% 2.14+-0.02 2% XIS1 1.94 -7% 2.09+-0.02 -1% XIS2 2.13 2% 2.10+-0.02 0% XIS3 2.15 3% 2.06+-0.02 -2%
Figure 1: Power-law fit to the Crab spectra of all the four XIS modules taken at the XIS-default position. All parameters were set free, allowing them to vary independently for each XIS module. The fit was carried out in the 1.0-10keV band, but excluding the interval 1.5-2.0 keV where a large systematic error associated with the Si K-edge remains.
- Flux and photon index (Ref. Suzaku memo 2006-34 )
- Energy band: soft band, HEASOFT ver: 6.2
- Under investigation
- Under investigation
- XIS-HXD cross-calibration
- Relative normalization factors of the XIS and HXD instruments are shown in Suzaku memo 2006-40
- Relative normalization factors of the XIS and HXD instruments are shown in Suzaku memo 2006-40
Related links
- Suzaku memo 2006-34 "The X-ray Telescope onboard Suzaku"
- Suzaku memo 2006-40 "Relative normalizations of XIS and HXD-PIN for V1.2.2.3 data"