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SLA_RVGALC - RV Corrn to Galactic Centre   

ACTION:
Velocity component in a given direction due to the rotation of the Galaxy.

CALL:
R = sla_RVGALC (R2000, D2000)

GIVEN:

R2000,D2000 R J2000.0 mean $[\,\alpha,\delta\,]$ (radians)

RETURNED:

sla_RVGALC R Component of dynamical LSR motion in direction R2000,D2000 (km s-1)

NOTES:
1.
Sign convention: the result is positive when the LSR is receding from the given point on the sky.
2.
The Local Standard of Rest used here is a point in the vicinity of the Sun which is in a circular orbit around the Galactic centre. Sometimes called the dynamical LSR, it is not to be confused with a kinematical LSR, which is the mean standard of rest of star catalogues or stellar populations.
3.
The dynamical LSR velocity due to Galactic rotation is assumed to be 220 km s-1 towards $l^{I\!I}=90^{\circ}$, $b^{I\!I}=0$.

REFERENCE:
Kerr & Lynden-Bell (1986), MNRAS, 221, p1023.


next up previous
Next: SLA_RVLG - RV Corrn to Local Group
Up: SUBPROGRAM SPECIFICATIONS
Previous: SLA_RVEROT - RV Corrn to Earth Centre

SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk