As an example, a special section is devoted here to the analysis of galactic velocity fields. The following programs are available:
ccdvel create a model velocity field, from scratch
rotcur tilted ring model velocity field fitting
rotcurshape annulus rotation curve shape fitting to a velocity field
% set r=$(B!F(Bnemoinp 0:60$(B!F(B
% set v=$(B!F(Bnemoinp 0:60 | tabmath - - "100*%1/(20+%1)" all$(B!F(B
% ccdvel out=map1.vel rad="$r" vrot="$v" pa=30 inc=60
% rotcurshape in=map1.vel radii=0,60 pa=30 inc=60 vsys=0 units=arcsec,1 \
rotcur1=core1,100,20,1,1 tab=-
% ccdmath out=map0.vel fie=0 size=128,128
% rotcurshape map0.vel 0,40 30 45 0 blank=-999 resid=map.vel \
rotcur1=plummer,200,10,0,0 fixed=all units=arcsec,1
Since rotcurshape computes a residual velocity field, one can easily create nice model velocity fields from any selected shape by ``fitting'' a rotation curve shape to a velocity field of all 0s and keeping all parameters fixed to the requested values:
% ccdmath out=map0.vel fie=0 size=128,128
% rotcurshape map0.vel 0,40 30 45 0 blank=-999 resid=map.vel \
rotcur1=plummer,200,10,0,0 fixed=all units=arcsec,1
% ccdplot map.vel -100:100:10 blankval=0 cmode=1