5
Radio: The “Spider” Isovelocity
Diagram, interpreting HI maps
V
rad
= V
sys
+ V
rot
sin
β
cos
θ
Where
β
is the inclination angle,
θ
is the angle relative to major axis,
And there are no non-circular velocities
So what might we expect to see for non-
circular velocities?
And from what effects?