Results from Saskatoon: A Measurement of the Anisotropy in the Cosmic Microwave Background
Session 118 -- Cosmic Micorwave Background
Oral presentation, Thursday, 12, 1995, 2:00pm - 3:30pm

[118.02D] Results from Saskatoon: A Measurement of the Anisotropy in the Cosmic Microwave Background

C.B. Netterfield, N.C. Jarosik, L.A. Page, D. Wilkinson, E.J. Wollack (Princeton University)

A measurement of the anisotropy in the CMBR is described. Two High Electron Mobility Transistor (HEMT) amplifier-based radiometers provide frequency coverage from 26 GHz to 46 GHz in 6 frequency bands and two polarizations. The observations were made from Saskatoon, Saskatchewan in January and February of 1994. There are two primary results: \\ 1) A previous detection of the anisotropy by this group (Wollack $et$ $al.$ 1993) is confirmed. The spectral index of the anisotropy is consistent with that of the CMBR. Both free-free emission and dust emission are ruled out as the sole source of the anisotropy. The root-mean-squared amplitude of the fluctuations for the combined data set is $44^{+12}_{-7} \mu\,$K. Expressed as the square root of the angular power spectrum in a band of multipoles between $l_{e}=69^{+29}_{-22}$, this is $\delta T_{l}=\sqrt{l(l+1)<|a_l^m|^2>} = 42^{+12}_{-7} \mu$K. \\ 2) The chopping scheme provides spatial sensitivity from $l=50$ to $l=150$ in 5 multipole bands, allowing a determination of the shape of the spatial power spectrum. With the fluctuations expressed as a power law in multipole moment, $\delta T_l=\delta T_{le}(l/l_e)^m$, a maximum likelihood analysis finds $\delta T_{le}=45^{+7}_{-6} \mu$K (not including the 14\% calibration uncertainty) and $m=-0.4^{+0.3}_{-0.4}$, with $l_e=82$. Thus, a mildly falling spectrum is favored at intermediate angular scales.