Table of Contents

**twspeed vel=**ccd-velocity **den=**ccd-density
[parameter=value]

*twspeed* assumes the line of nodes is along
the X-axis, the galaxy center and position angle are keywords but not implemented
yet?

In the following (x,y) are defined along the major and minor axis
of the galaxy resp., and pspeed will then compute the numerical sums

V(y) = SUM ( vel(x,y) * den(x,y)) / SUM ( den(x,y) ) X(y) = SUM ( x * den(x,y)) / SUM ( den(x,y) )where the summation is along

The output will be a table which can be inspected for signal and noise, and fed into a least squared fitter, such asV = Omega * SIN(inc) * X

**vel=***vel-file*- input file, must be the radial velocity in
*image(5NEMO)*format [no default]. **den=***int-file*- input file, must be the intensity in
*image(5NEMO)*format [no default]. **xin=***int-file*- input mean position image (optional)
**pa=**- *** Position Angle of disk [90]
**inc=**- *** Inclincation of the disk [0]
**center=**- *** Center of galaxy (map-center) []
**step=**- Slit width in pixels [1]
**window=**- Window functions (0=none, ..) [0]

% mkdisk disk1 10000 harmonic mass=1 % snapscale disk1 disk2 rscale=1,0.5,0 vscale=0 % snapspin disk2 disk3 omega=1 % snaprotate disk3 disk4 30 x % snapgrid disk4 ccd4-den moment=0 % snapgrid disk4 ccd4-vel moment=-1 % twspeed ccd4-vel ccd4-den > ccd4.tab % tabnllsqfit ccd4.tab Fitting a+bx: a= -5.11039e-05 0.000116198 b= -0.499963 0.00931362

~/src/pjt/imagetwspeed.c

17-Aug-87Original created as pspeed (though never made it into NEMO)PJT 18-nov-031.0: documented the new twspeed versionPJT 22-apr-041.1: changed order of keywordsPJT