# An Upper Limit to Arcminute Scale Anisotropy in the Cosmic Microwave Background Radiation at 142 GHz

Source: [An Upper Limit to Arcminute Scale Anisotropy in the Cosmic Microwave Background Radiation at 142 GHz](<https://www.sota2.com/research/paper/68fa244f2c2a3760193a26af>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T09:03:37.711Z

Authors: S. E. Church, K. M. Ganga, P. A. R. Ade, W. L. Holzapfel, P. D. Mauskopf, T. M. Wilbanks, A. E. Lange

Published: 1997-02-21T22:08:52.000Z

## Abstract

We present limits to anisotropies in the cosmic microwave background radiation (CMB) at angular scales of a few arcminutes. The observations were made at a frequency of 142 GHz using a 6-element bolometer array (the Sunyaev-Zel'dovich Infrared Experiment) at the Caltech Submillimeter Observatory. Two patches of sky, each approximately 36'x4' and free of known sources, were observed for a total of 6-8 hours each, resulting in approximately 80 independent 1.7' full-width half-maximum pixels. Each pixel is observed with both a dual-beam and a triple-beam chop, with a sensitivity per pixel of 90-150 uK in each chop. These data have been analyzed using maximum likelihood techniques by assuming a gaussian autocorrelation function for the distribution of CMB fluctuations on the sky. We set an upper limit of Delta T/T \<= 2.1 x 10^{-5} (95% confidence) for a coherence angle to the fluctuations of 1.1. These limits are comparable to the best limits obtained from centimeter-wavelength observations on similar angular scales but have the advantage that the contribution from known point sources is negligible at these frequencies. They are the most sensitive millimeter-wavelength limits for coherence angles \<= 3'. The results are also considered in the context of secondary sources of anisotropy, specifically the Sunyaev-Zel'dovich effect from galaxy clusters.

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/astro-ph/9702196>)

[PDF](<https://arxiv.org/pdf/astro-ph/9702196.pdf>)