mkwingsurf - Part of the wingscan suite of scripts. Calculates the surface brightness.
mkwingsurf uses an IRAF-compatible parameter interface. A template parameter file is in /proj/axaf/simul/lib/uparm/mkwingsurf.par
Name of the input file. If input equals 'stdin', mkwingsurf reads input from STDIN.
Name of the output file. If output equals 'stdout' or 'stderr', mkwingsurf writes output to STDOUT or STDERR, respectively.
Mirror focal length in millimeters.
Name of the energy column in the input file.
Name of the shutters column in the input file.
Name of the direction column in the input file.
Name of the aperture diameter column in the input file.
Name of the radius column in the input file. The radius column specified the radial distance of the aperture center from the FOA in the two dimensional focal plane.
Name of the effective area column in the input file.
Name of the effective area error column in the input file.
Name of the effective area through a 35 millimeter aperture with a full shell column in the input file.
Name of the effective area error through a 35 millimeter aperture with a full shell column in the input file.
Name of the wing correction column in the output table.
Name of the wing correction parameter0 column in the output table.
Name of the wing correction parameter1 column in the output table.
Name of the wing correction parameter2 column in the output table.
Name of the wing correction reduced chi squared column in the output table.
Name of the surface brightness column in the output file.
Name of the surface brightness error column in the output file.
Override fit parameters. This parameter takes a comma or space seperated list of parameters in the form keyword.attribute=value. Valid keywords are par0, par1, par2. Valid attributes are value, min, max, step, fitme.
Name of the PGplot device on which the fits will be displayed. See PGPlot manul for a complete list. 'none' turns off the plotting option.
The range over which the fit is performed. The range is specified by the index of the first and last element in the range, seperated by a colon, ':'. '0:' causes the fit to be performed over all points. The independant variable in the fits is radius and the dependant variable is surface brightness.
If set to 'yes', print this help information and exit.
If set to 'yes', print version information and exit.
mkwingsurf filters the input file passing all existing columns through to the output. It adds columns, whose names are specified by the surfbrt, surfbrterr, wingcorr, par0, par1, par2, and reduced_chi2 parameters, to the output file. surfbrt specifies the surface brightness of the measurement.
Surface brightnesses are calculated by grouping measurements by energy, shutter configuration, and direction of the optics tilt. Foreach dataset, the surface brightness is calculated by fitting a powerlaw modified by an exponential to obtain a wing correction. This wing correction accounts for the steeply falling PSF measured across a finite sized aperture.
The input file must contain columns with the effective area through a 35 mm aperture at the same energy and for the full shell corresponding to the quadrant through which the wingscan measurement was taken. This Aeff35 is used to normalize the effective area or the wingscan measurement.
The fit function for the wing correction has three parameters. These
parameters may be modified via the override parameter. The function is of the form par0 * x ^ ( - par1 ) *
exp( - x / par2 ). It is necessary to obtain the wing
correction iteratively. We begin by assuming the power-law index, gamma,
equals 2. Then we compute surface brightnesses and fit the surface
brightness to an exponentially truncated power-law. We take the logarithmic
derivative of the hypergeometric function to obtain the local powerl-law
index gamma at each data point, recompute the wing correction using the
hypergeometric function and iterate until the change in the pinhole
correction is less than or equal to 0.01 or 5 iterations, whichever is
smaller.
For further discussions on the exact formulae and algorithms used please refer to the Wing Scans: Analysis chapter of the XRCF Phase 1 Testing: Analysis Results. http://hea-www.harvard.edu/MST/simul/xrcf/report/chaps/wingscan_1up.ps
If the user wishes to integrate the fit to the surface brightnesses to determine the extra effective area beyond the 35 aperture, the program pow_exp_integral will enable them to do so.
Presently all the center points are thrown out...is that right? Tenatively, yes.
M. Tibbetts ( mtibbetts@head-cfa.harvard.edu )