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snapaxsym - generates an around-axis integrated ccd-like frame of an N-body snapshot


snapaxsym in=snapshot out=image [parameter=value]


snapaxsym makes a ccd frame from an N-body snapshot, by binning the (r,z) in the cylindrical coordinate of all stars on a regular rectangular (square) grid and assigning a mean integrated ’local density’ (integrated around z-axis, i.e. by assuming the axial symmetry around the z-axis, units: mass (intensity). There is an option which produces the map of rotation velocity insted of the density The ccd frame is written to a standard Image(5) output file, and can be accessed by various other programs for smoothing, display etc.

snaprotate(1NEMO) has to be used first to set the axis of the symmetry not parallel to the coordinate axis.


The following parameters are recognized in any order if the keyword is also given:
input file, must be in SnapShot(5) format [no default].
output file, will be in Image(5) format [no default].
Only data frames with time values within time-range, which is of the form, eg, "1.0:1.5,2.5,3.0", will be translated. [default: all].
Size of the CCD frame in sky units. Note that the picture is forced to be square [default: 5.0].
Cell- or pixel size. Again they will be square. For a 2D matrix this value will be set by the header of that dataset. [default: 0.1].
Logical if the map of rotational velocity is requested. [default: f].

See Also

snapccd(1NEMO) , snaprotate(1NEMO) , ccdsmooth(1NEMO)


The values of density of the cells closest to the axis of symmetry may be erratic.


Jun Makino

Update History

7-Dec-88    V1.0: Created    JM
7-jul-89    V1.2: get_snap()    PJT

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