ball1.gif IAC-Bartol

Femenía et al. use data from the 3.3, 2.1, and 1.3 mm channels of the ground-based IAC-Bartol experiment at Tenerife to constrain CMBR anisotropy.

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

W_\ell = 3.158  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 $\Phi_0 = 2.6^\circ$ is half of the peak-to-peak chop angle. The normalization, $3.158$, 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 250. The second column is the zero-lag $W_\ell$.

Table: IAC-Bartol zero-lag Window Function Parameters
$\ell_{e^{-0.5}}$ $\ell_{\rm e}$ $\ell_{\rm m}$ $\ell_{e^{-0.5}}$ $\sqrt{I(W_\ell)}$
38 52.7 56 77 1.01

The quoted bandtemperature values are from Femenía et al. and account for the calibration uncertainty of 20% as a systematic effect (i.e., this is not added in quadrature to the statistical 1 $\sigma$ error bars).

Fig.: IAC-Bartol zero-lag window functions. (Postscript version here.) win_IAC-Bartol.gif


ball23.gifLink to the experiment webpage.

B. Femenía, R. Rebolo, C.M. Gutiérrez, M. Limon, and L. Piccirillo, ``The Instituto de Astrofísica de Canarias-Bartol Cosmic Microwave Background Anisotropy Experiment: Results of the 1994 Campaign", Astrophys. J. 498, 117 (1998).

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