def Omega(self):
r"""Return the beam solid angle :math:`\int |A(\boldsymbol{n})|^2 \ d^2\boldsymbol{n}`."""
nside = 256
angpos = hputil.ang_positions(nside)
lat = np.radians(44.15268333) # exact value not important
lon = np.radians(91.80686667) # exact value not important
zenith = np.array([0.5*np.pi - lat, lon])
horizon = visibility.horizon(angpos, zenith)
pxarea = (4 * np.pi / (12 * nside**2))
om = np.zeros_like(self.freqs)
for fi in xrange(len(self.freqs)):
width = self.width / (const.c / (1.0e9 * self.freqs[fi]))
beam = cylbeam.beam_amp(angpos, zenith, width, self.fwhm_h, self.fwhm_h)
om[fi] = np.sum(np.abs(beam)**2 * horizon) * pxarea
return om
def response(self, xyz):
"""Beam response across active band for specified topocentric coordinates.
This uses the beam model implemented in driftscan package.
Parameters
----------
xyz : array like, of shape (3, ...)
Unit direction vector in topocentric coordinates (x=E, y=N, z=UP).
`xyz` may be arrays of multiple coordinates.
Returns
-------
Returns 'x' linear polarization (rotate pi/2 for 'y') of shape (nfreq, ...).
"""
xyz = np.array(xyz)
lat = np.radians(44.15268333) # exact value not important
lon = np.radians(91.80686667) # exact value not important
zenith = np.array([0.5*np.pi - lat, lon])
m = top2eq_m(lat, lon) # conversion matrix
shp = xyz.shape
p_eq = np.dot(m, xyz.reshape(3, -1)).reshape(shp) # point_direction in equatorial coord
p_eq = coord.cart_to_sph(p_eq.T) # to theta, phi
# cylinder width in wavelength
width = self.width / (const.c / (1.0e9 * self.freqs))
nfreq = len(self.freqs)
resp = np.zeros((nfreq,)+xyz.shape[1:])
for fi in xrange( nfreq):
resp[fi] = cylbeam.beam_amp(p_eq, zenith, width[fi], self.fwhm_h, self.fwhm_h)
# resp[fi] = cylbeam.beam_amp(p_eq, zenith, width[fi], self.fwhm_e, self.fwhm_h) # for X dipole
# resp[fi] = cylbeam.beam_amp(p_eq, zenith, width[fi], self.fwhm_h, self.fwhm_e) # for Y dipole
return resp
