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XMM-Newton Science Analysis System


omphotom (omphotom-0.6.6) [xmmsas_20070708_1801-7.1.0]

Meta Index / Home Page / Photometry

Point sources

There are 6 methods (parameter phototype= 0, 1, 2, 3, 4, 5, or 6) available for recomputing the photometry of a point-source. The method to be used for a given source is set by the parameter ``phototype''.

For FAST mode data, the background image can be obtained from the IMAGING image containing that source, if it exists.

1. phototype=0 Aperture photometry using the specified aperture and inner and outer background annulus radii and the background subtracted using the given background image (if parameter backgroundsetïs not set then the background is obtained from the actual image. If no background image is given the input image will be used instead.

2. phototype=1 Aperture photometry using the specified aperture and inner and outer background annulus radii and the background subtracted using the given value for the background counts per pixel (parameter background¨).

3. phototype=2 Least-squares fit to the point-spread function, excluding a constant term, using a background determined from the background annulus.

4. phototype=3 A least-squares fit to the point-spread function, for one or more sources), which includes a constant term for the background.

5. phototype=4 Least-squares fit to the point-spread function for one or more sources, excluding the background. The background is subtracted using a given value for the background counts per pixel.

6. phototype=5 Least-squares fit to the point-spread function for one or more sources, including the background and source-position.

7. phototype=6 Least-squares fit to the point-spread function for one or more sources, including the source-positions, but excluding a fit to the background.