rgsext: convolve an RGS spectrum for extended emission
This model convolves the input spectrum by an angular structure
function so that it can be used with the standard RGS response matrix,
which assumes a point source. This will only be of value for
moderately extended (one arcmin) sources. It is a modification of the
rgsxsrc model with an extra parameter to provide additional
smoothing above that provided by the image. The smoothing factor
stretches the angular structure function by the parameter value.
The angular structure function depends on an input image,
boresight position and extraction region size. There are two ways of
passing this information to the model. Either the information can be
given by three XFLTnnnn keywords in the spectrum or the information
can be read from an external file.
An example of the first option is to include the keywords:
XFLT0001 = 'Image:/local/data/mymachine/myusername/mos1.fit'
XFLT0002 = 'Boresight:05:25:02.9 -69:38:30 339.760974'
XFLT0003 = 'Extraction:1.8'
For the second option, the xset variable RGS_XSOURCE_FILE
should be set to the name of the file containing the information. An
example of this file is:
RGS_XSOURCE_IMAGE /local/data/mymachine/myusername/mos1.fit
RGS_XSOURCE_BORESIGHT 05:25:02.9 -69:38:30 339.760974
RGS_XSOURCE_EXTRACTION 1.8
The RA and Dec of the source can be determined from the image or from
the headers of the source spectrum. The position angle can be found in
the image headers.
The model parameters are:
par1 |
order: grating order (must be negative) |
par2 |
factor: additional smoothing factor (1 means no change) |
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Last modified: Friday, 21-Mar-2025 11:56:20 EDT
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