Detection of Cosmic Microwave Background Anisotropy by the Third Flight of MSAM

The third flight of the Medium Scale Anisotropy Measurement (MSAM1), in June 1995, observed a new strip of sky, doubling the sky coverage of the original MSAM1 dataset. MSAM1 observes with a 0. 5 beam size in four bands from 5–20 cm. From these four bands we derive measurements of cosmic microwave background radiation (CMBR) anisotropy and interstellar dust emission. Our measurement of dust emission correlates well with the 100 μm IRAS Sky Survey Atlas; from this comparison we determine an effective emissivity spectral index between 100 μm and 444 μm of 1.46± 0.28. Analysis of our measurement of CMBR anisotropy shows that for Gaussian-shaped correlation functions with θc = 0. 3, we place a limit on total rms anisotropy of 2.2× 10 < ∆T/T < 3.9× 10 (90% confidence interval, including calibration error). The band-power limits are 〈δT 〉 ≡ 〈l(l + 1)Cl/2π〉 = 50 −11 μK at l = 160, and 〈δT 〉 = 65 −13 μK at l = 270 (1 σ limits, including calibration error). The corresponding limits with statistical errors only are 〈δT 〉 = 50 −9 μK and 〈δT 〉 = 65 −10 μK respectively. These measurements are consistent with a standard adiabatic cold dark matter model; we discuss constraints on h, n, and the redshift of reionization. NASA/Goddard Space Flight Center, Laboratory for Astronomy and Solar Physics, Code 685.0, Greenbelt, MD 20771 Global Science and Technology, Inc., NASA/GSFC Laboratory for Astronomy and Solar Physics, Code 685.0, Greenbelt, MD 20771 Applied Research Corporation, NASA/GSFC Laboratory for Astronomy and Solar Physics, Code 685.0, Greenbelt, MD 20771 University of Chicago, 5640 S. Ellis St., Chicago, IL 60637 CITA, University of Toronto, Toronto, Ontario M5S 3H8, Canada Department of Physics, University of California, Santa Barbara, CA 93106