ball1.gif FIRS

Ganga et al. use data from the 170 GHz channel of the balloon-borne FIRS (Far Infrared Survey) experiment to constrain CMBR anisotropy.

The FWHM of the beam, assumed to be gaussian, is $\sigma_{\rm FWHM} =
3.8^\circ$. The zero-lag window function is

W_\ell = e^{-\sigma_{\rm G}{}^2 (\ell + 0.5)^2} ,

where $\sigma_{\rm G} = \sigma_{\rm FWHM}/\sqrt{8 {\rm ln} 2}$.

The first column in the window function file is $\ell$, which runs from 2 to 130. The second column is $W_\ell$.

Table: FIRS zero-lag Window Function Parameters
$\ell_{e^{-0.5}}$ $\ell_{\rm e}$ $\ell_{\rm m}$ $\ell_{e^{-0.5}}$ $\sqrt{I(W_\ell)}$
(2) 10.8 2 25 1.62

The quoted bandtemperature values are from Bond, with 7% added in quadrature to his statistical 1 $\sigma$ error bars to account for the FIRS 1 $\sigma$ calibration uncertainty.

Fig.: FIRS zero-lag window functions. (Postscript version here.) win_FIRS.gif


ball23.gifLink to the experiment webpage.

J.R. Bond, ``Signal-to-Noise Eigenmode Analysis of the Two-Year COBE Maps", Phys. Rev. Lett. 74, 4369 (1995).

K. Ganga, E. Cheng, S. Meyer, and L. Page, ``Cross-Correlation Between the 170 GHz Survey Map and the $COBE$ Differential Microwave Radiometer First-Year Maps", Astrophys. J. Lett. 410, L57 (1993).

K. Ganga, L. Page, E. Cheng, and S. Meyer, ``The Amplitude and Spectral Index of the Large Angular Scale Anisotropy in the Cosmic Microwave Background Radiation", Astrophys. J. Lett. 432, L15 (1994).

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