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Дата изменения: Tue Sep 20 19:45:21 2011
Дата индексирования: Mon Apr 11 03:38:46 2016
Кодировка:
Поисковые слова: dwarf spheroidal

Calibration Access and Data Handbook

Description

This CCF component is used by the SAS. The radial PSF distribution of the filter FilterId is tabulated in the extension PSF-FilterId. Azimuthal symmetry is assumed.
There is one extension per non-dispersive filter element and two extensions for each grisms. Thus in total there are 12 other binary table extension in the PSF1DRB CCF component, with the names:

PSF1DRB extension	comment
name
PSF-U	radial PSF of U-filter
PSF-B	radial PSF of B-filter
PSF-V	radial PSF of V-filter
PSF-UVW1	radial PSF of UVW1-filter
PSF-UVM2	radial PSF of UVM2-filter
PSF-UVW2	radial PSF of UVW2-filter
PSF-WHITE	radial PSF of WHTIE-filter
PSF-MAGNI	radial PSF of magnifier
PSF-GRISM1	radial PSF of UV grism 1st order (TBC)
PSF-GRISM2	radial PSF of visible grism 1st order (TBC)
PSF-GRISM10	radial PSF of UV grism 0th order (TBC)
PSF-GRISM20	radial PSF of visible grism 0th order (TBC)

In the photometric calibration analysis a fixed aperture for each filter is used to extract the source counts. The value of the cumulative PSF is normalized to 1.0 at this fixed aperture radius. The aperture radius is listed for each filter elements in the keyword APERTURE. The integrated flux within the radius APERTURE. is defined to contain 100% of the source flux. The aperture radii in the analysis of UV data are generally larger than in the visible. Therefore the aperture radius is listed separately for each filter in the keyword APERTURE of the filter extensions.

The stretching of the PSF as function of field position is described as function of the distance r between the detector location (x,y) and the boresight, i.e. as function of

$$r=\sqrt{(x-1024.5)^2+(y-1024.5)^2}$$

. The functional form is a third order polynomial in r (cf. section 3.5.9). The parameters of the third order polynomial are stored as keywords in the extension headers.

In the binary extensions the radial PSF at the central detector position of the specified filter is stored as integrated intensity (column INTENSITY) between the radial bins RMIN and RMAX. The PSF is stored for different count to framerate ratios (column CFRR).

The binary extensions have the follow structure:

Binary table: PSF-FilterId

keyword	keyword	keyword	keyword	comment
name	type	unit	value	comment
APERTURE	E	pixel	varies	aperture radius of photometric calibration
PARX0Y0	E	not applicable	varies
PARX1Y0	E	not applicable	varies
PARX2Y0	E	not applicable	varies
PARX3Y0	E	not applicable	varies
PARX0Y1	E	not applicable	varies
PARX1Y1	E	not applicable	varies
PARX2Y1	E	not applicable	varies
PARX0Y2	E	not applicable	varies
PARX1Y2	E	not applicable	varies
PARX0Y3	E	not applicable	varies

column name	column type	column unit	comment
CFRR	E	counts/frame/resolution element	count to framerate ratio
RMIN	20E	subpixel	lower radius limit of bin
RMAX	20E	subpixel	upper radius limit of bin
INTENSITY	20E	not applicable	intensity in [RMIN,RMAX]