ball1.gif White Dish

Tucker et al. use 90 GHz data from the ground-based White Dish experiment at the South Pole to constrain CMBR anisotropy. Ratra et al. (1998) summarize the experiment.

The FWHM of the beam, assumed to be gaussian, is $\sigma_{\rm FWHM} =
12^\prime$. The zero-lag window function of the two-beam Method I (see Tucker et al. or Ratra et al. 1998) experiment is

W_\ell = e^{-\sigma_{\rm G}{}^2 (\ell + 0.5)^2}
[2 - 2 P_\ell ({\rm cos}(2\Phi_0))] ,

where $\sigma_{\rm G} = \sigma_{\rm FWHM}/\sqrt{8 {\rm ln} 2}$, $P_\ell$ is a Legendre polynomial of order $\ell$, and $\Phi_0 = 7.5^\prime$ is half of the peak-to-peak chop angle.

The first column in the window function file is $\ell$, which runs from 2 to 2500. The second column is the White Dish Method I zero-lag $W_\ell$.

Table: White Dish zero-lag Window Function Parameters
$\ell_{e^{-0.5}}$ $\ell_{\rm e}$ $\ell_{\rm m}$ $\ell_{e^{-0.5}}$ $\sqrt{I(W_\ell)}$  
297 476.9 539 825 1.18  

The quoted bandtemperature values are from Ratra et al. (1998). They were computed assuming a flat bandpower spectrum and, following Ganga et al. (1997), account for the White Dish absolute calibration uncertainty of 30%.

Ratra et al. (1998, 1999) use the White Dish data to constrain cosmological parameters.

Fig.: White Dish zero-lag window functions. (Postscript version here.) win_WhiteDish.gif


ball23.gifLink to the experiment webpage.

K. Ganga, B. Ratra, J.O. Gundersen, and N. Sugiyama, ``UCSB South Pole 1994 Cosmic Microwave Background Anisotropy Measurement Constraints on Open and Flat-$\Lambda$ Cold Dark Matter Cosmogonies", Astrophys. J. 484, 7 (1997).

B. Ratra, K. Ganga, N. Sugiyama, G.S. Tucker, G.S. Griffin, H.T. Nguyên, and J.B. Peterson, ``Using White Dish CMB Anisotropy Data to Probe Open and Flat-$\Lambda$ CDM Cosmogonies", Astrophys. J. 505, 8 (1998).

B. Ratra, R. Stompor, K. Ganga, G. Rocha, N. Sugiyama, and K.M. Górski, ``Cosmic Microwave Background Anisotropy Constraints on Open and Flat-$\Lambda$ Cold Dark Matter Cosmogonies from UCSB South Pole, ARGO, MAX, White Dish, and SuZIE Data", Astrophys. J. 517, 549 (1999).

G.S. Tucker, G.S. Griffin, H.T. Nguyên, and J.B. Peterson, ``A Search for Small-Scale Anisotropy in the Cosmic Microwave Background", Astrophys. J. Lett. 419, L45 (1993).

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