Calibration Access and Data Handbook

Description

Currently not used in the SAS, but may be in the future. Is a placeholder that was supposed to have either some real background spectra or some coefficients with which to generate background spectra. It is currently not used, however might by used for a future task that takes as input some proxies like the RA & Dec, the ROSAT broad band count rates for the target location, the corner count rates etc. and generates a best guess background file.

One extension containing calibrated event list of low background data, with brighter point sources removed.

The CCF contains the following tables:

PARTICLE :

Accessed by :

• CAL_getParticleBackground(): Obtain background particle spectrum in PI channel space according to the model :

  $bg = PAR[0] + PAR[1] \times PI [Hz/mm^{2}/chan]$

Attributes:

EV_2_PI:

eV per PI channel (unused)

Columns:

PAR:

model parameters; two-row scalar columns

X_RAY_DIFFUSE :

Accessed by :

• CAL_getDiffuseXBackground(): Returns a ready made diffuse X-ray spectrum in PI space from the data in the SPECTRUM column modified by a second order polynomial:

  $spec = SPECTRUM \times (PAR[0] + PAR[1] \times r + PAR[2] \times r^{2})$

  where r = radial offset from on-axis [mm]; is input to routine.

Attributes:

EV_2_PI:

eV per PI channel (unused)

Columns:

FILTER_ID:

meant to be the filter ID but contains currently an invalid entry and is ignored by the CAL

SPECTRUM:

unmodulated PI background PI spectrum

X_RAY_DIFFUSE_MODULATION :

Accessed by :

• CAL_getDiffuseXBackground(): see above.

Attributes:

none.

Columns:

PAR:

3-row scalar column with modulation parameters (see above).