ball1.gif Saskatoon 1993

Wollack et al. use Ka band (centered on 30 GHz) data from the ground-based Saskatoon 1993 experiment at Saskatoon to constrain CMBR anisotropy.

The FWHM of the beam, assumed to be gaussian, is $\sigma_{\rm FWHM} =
0.65^\circ \sqrt{8 {\rm ln} 2}$. The zero-lag window function of the stepped-scan, second harmonic lockin, three-beam experiment is

W_\ell = 1.839  e^{-\sigma_{\rm G}{}^2 (\ell + 0.5)^2}
... J_2 \left( (\ell - 2k)
\Phi_0 \right) \right]^2 ,

where $\sigma_{\rm G} = \sigma_{\rm FWHM}/\sqrt{8 {\rm ln} 2}$, $J_2$ is a Bessel function of the first kind, and $\Phi_0 = 2.45^\circ$ is half of the peak-to-peak chop angle. The normalization, $1.839$, is fixed so that a 1 $\mu$K change in a blackbody filling only the positive lobe of the sky pattern gives a detected signal of 1 $\mu$K.

The first column in the window function file is $\ell$, which runs from 2 to 350. The second column is the zero-lag $W_\ell$.

Table: Saskatoon 1993 zero-lag Window Function Parameters
$\ell_{e^{-0.5}}$ $\ell_{\rm e}$ $\ell_{\rm m}$ $\ell_{e^{-0.5}}$ $\sqrt{I(W_\ell)}$
47 67.0 69 95 1.07

The quoted bandtemperature values are computed for a flat bandpower spectrum. They are from Netterfield et al., corrected according to the caption of Figure 3 of Torbet et al. (to account for re-calibration and foreground contamination), with 11% added in quadrature to their statistical 1 $\sigma$ error bars to account for the 1 $\sigma$ calibration uncertainty.

Fig.: Saskatoon 1993 zero-lag window functions. (Postscript version here.) win_Saskatoon93.gif


ball23.gifLink to the experiment webpage.

C.B. Netterfield, M.J. Devlin, N. Jarosik, L. Page, and E.J. Wollack, ``A Measurement of the Angular Power Spectrum of the Anisotropy in the Cosmic Microwave Background", Astrophys. J. 474, 47 (1997).

E. Torbet, et al., ``A Measurement of the Angular Power Spectrum of the Microwave Background Made from the High Chilean Andes", astro-ph/9905100 v3.

E.J. Wollack, N.C. Jarosik, C.B. Netterfield, L.A. Page, and D. Wilkinson, ``A Measurement of the Anisotropy in the Cosmic Microwave Background Radiation at Degree Angular Scales", Astrophys. J. Lett. 419, L49 (1993).

Bharat Ratra and Tarun Souradeep
Department of Physics, Kansas State University
Last updated: 2000-08-31