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TopHat in Antarctica

The first phase of the Medium-Scale Anisotropy Measurement (MSAM1) is completed. It probed CMBR anisotropy at 0.5 degree angular scales between 5 and 23 icm (150 and 700 GHz, 0.4 and 2.0 mm). Fluctuations at these angular scales are believed to be the precursors of the largest structures we observe today.

The first flight of this package (MSAM1-92 : June 1992 from Palestine, TX) resulted in a detection of 0.5 x 10-5 <dT/T< 2 x 10-5. The second flight (MSAM1-94 : June 1994 from Palestine, TX) observed the same region of sky and produced a measurement in statistical agreement with the 1992 observation.

This region of the sky is also the first independently confirmed observation of medium-scale CMBR anisotropy via the Princeton SK experiment . This confirmation occurred at a much lower frequency enabling us to rule out certain foreground contamination as a possible source of signal. The final flight (MSAM1-95: June 1995 from Palestine, TX) observed an independent patch of sky more than doubling the sky coverage of the previous two flights. The results from all three flights have been published, and a final, combined analysis is nearly complete.