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Function: beam_pattern()

void beam_pattern(float theta, float phi, float psi, float *plus, float *cross)

This routine computes the beam pattern functions, $F_+$ and $F_\times$, for some specified angles $\theta$, $\phi$, and $\psi$. The arguments are:

theta: Input. The polar angle $\theta$ (radians from zenith).
phi: Input. The azimuthal angle $\phi$ (radians counter-clockwise from the first arm).
psi: Input. The polarization angle $\psi$ (radians).
plus: Output. The detector response function $F_+$.
cross: Output. The detector response function $F_\times$.

The beam pattern functions are calculated according to the following formulae:

\begin{displaymath}
F_+ = {\textstyle\frac{1}{2}}(1+\cos^2\theta)\cos2\phi\, \cos2\psi
- \cos\theta\, \sin2\phi\, \sin2\psi
\end{displaymath} (12.6.284)

and
\begin{displaymath}
F_\times = {\textstyle\frac{1}{2}}(1+\cos^2\theta)\cos2\phi\, \sin2\psi
+ \cos\theta\, \sin2\phi\, \cos2\psi.
\end{displaymath} (12.6.285)

Author: Jolien Creighton, jolien@tapir.caltech.edu
Comments: The beam pattern formulae, as well as a precise definition of the angles can be found in: Kip Thorne in 300 Years of Gravitation, S. Hawking and W. Israel editors (Cambridge University Press, 1987). The formulae are suitable for detectors in which the arms are perpendicular; they are not suitable for the GEO-600 site because the opening angle is approximately $94^\circ$.


next up previous contents
Next: Function: mc_chirp() Up: Galactic Modelling Previous: Function: equatorial_to_horizon()   Contents
Bruce Allen 2000-11-19