Measurements of Anisotropy in the Cosmic Microwave Background Radiation at Degree Angular Scales Near the Stars Sigma Hercules and Iota Draconis

A. C. Clapp, M. J. Devlin, J. O. Gundersen, C. A. Hagmann, V. V. Hristov, A. E. Lange, M. Lim, P. M. Lubin, P. D. Mauskopf, P. R. Meinhold, P. L. Richards, G. F. Smoot, S. T. Tanaka P. T. Timbie, C. A. Wuensche

Published 1994-04-28, updated 1994-05-01Version 3

We present results from two four-frequency observations centered near the stars Sigma Hercules and Iota Draconis during the fourth flight of the Millimeter-wave Anisotropy eXperiment (MAX). The observations were made of 6 x 0.6-degree strips of the sky with 1.4-degree peak to peak sinusoidal chop in all bands. The FWHM beam sizes were 0.55+/-0.05 degrees at 3.5 cm-1 and a 0.75+/-0.05 degrees at 6, 9, and 14 cm-1. Significant correlated structures were observed at 3.5, 6 and 9 cm-1. The spectra of these signals are inconsistent with thermal emission from known interstellar dust populations. The extrapolated amplitudes of synchrotron and free-free emission are too small to account for the amplitude of the observed structures. If the observed structures are attributed to CMB anisotropy with a Gaussian autocorrelation function and a coherence angle of 25', then the most probable values are DT/TCMB = (3.1 +1.7-1.3) x 10^-5 for the Sigma Hercules scan, and DT/TCMB = (3.3 +/- 1.1) x 10^-5 for the Iota Draconis scan (95% confidence upper and lower limits). Finally a comparison of all six MAX scans is presented.