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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
(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 uv 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
FWHM of the primary beam.

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Erik Leitch
20010416