Conclusions

As of sunrise 2000, we have obtained more than 1000 hours of usable data on three sets of eight fields, or over 42 hours per field. DASI images of these fields are shown in Figure 7, with rms noise in each field less than $10~{\rm\mu K}$ (note, however, that these maps have been corrected for the primary beam, so that the signal/noise decreases by a factor of two at the edge).

Figure 6 shows the estimated errors on power spectrum measurements given the data collected so far. Note that this is not a power spectrum measured by DASI, but a power spectrum recovered from realistic simulations of the CMBR, with sky coverage and noise appropriate for the data in hand. Errors on these estimates reflect actual data editing and scatter, baseline correlations due to the overlap of antenna apertures in the u-v plane, and correlations introduced by the ground subtraction.

 

Figure: Expected errors on the measured DASI power spectrum, where visibilities have been combined into 10 bins. Points are the power spectrum recovered from a set of 24 simulated CMBR fields, drawn from the power spectrum given by the solid line. No point sources were included in these simulations.

 

Figure: DASI images of 24 CMBR fields, where maps have been corrected for the primary beam taper. Each circle represents the $3\fdg 4$ FWHM of the primary beam.

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