Table of Contents

Begeman’s
(1989, Appendix B, eq.(8)
) recipe reads as follows:

v = V + b^2/n * ( Vx*Nx + Vy*Ny + N * (Vxx + Vyy) / 2)where the correction terms (

**inD=**- Input Model Density image file []
**inV=**- Input Model Velocity image file []
**ind=**- Input Observed (smoothed) Density image file []
**inv=**- Input Observed (smoothed) Velocity image file []
**out=**- Output file, depends on the values of
**diff=**and**beeg=**. **beam=**- Override sigma_beam/pixel ratio. Recall FWHM = 2.355 * SIGMA. By default the beam size will be in the header.
**diff=f|t**- Compute a Difference map? (as opposed to Computed Observed). Normally the Observed velocity field is computed from the Model and BSC terms, but turning this option on, the input Observed is subtracted from the computed Observed. [f]
**beeg=t|f**- Use the Begeman correction terms. This is of course the default, but by turning this off, a simple different of V-v (Model - Observed) can be computed, as can be seen in the EXAMPLES below. [t]

testbsc N.ccd V.ccd n.ccd v.ccd map1 diff=f beeg=f testbsc N.ccd V.ccd n.ccd v.ccd map2 diff=t beeg=f testbsc N.ccd V.ccd n.ccd v.ccd map3 diff=f beeg=t testbsc N.ccd V.ccd n.ccd v.ccd map4 diff=t beeg=tNow the four maps will have the following meaning:

map1: V map2: V - v map3: V + bsc (should be close to ’v’) map4: V + bsc - v (should be close to 0)

3-jul-2019V0.4 Created/releasedPJT