CARA Science: Python


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Summary

Python is one of the instruments in CARA that study the cosmic microwave background radiation (CMBR). It was at the Pole from 1992-1997.

Python was a 0.75-meter telescope which detected and characterized anisotropy in the cosmic microwave background (CMB) radiation at sub-degree angular scales. The experiment operated successfully for five summer seasons at the Pole. In the first three years of observations, the telescope was outfitted with a four pixel bolometric photometer operating at 90 GHz. In the last two years of observations, the photometer was replaced by a two pixel HEMT amplifier-based radiometer operating at 40 GHz.

Results

The same region of sky, uncontaminated by any known foregrounds, was observed at both 40 and 90 GHz. A joint analysis of the 40 and 90 GHz data sets confirms that the anisotropy observed is consistent with that expected from the CMB. In its last year of observations the Python experiment sampled approximately 600 square degrees of sky (see Figure 1). The large sky coverage, high signal to noise ratio, and low contamination due to foregrounds allowed a reliable and robust determination of the CMB power spectrum as shown in Figure 2.

Python has detected structure in the CMBR on angular scales of 0.91°, 2.75°, and 5.5°, at two different wavelengths, and at more than a hundred points on the sky. Its data are among the most extensive, most precise, and best confirmed measurements yet made of intermediate-scale anisotropy.

A much more detailed summary can be found on the group's website.

Pictures

For more information

The group has a website at http://cmbr.phys.cmu.edu/pyth.html .

Python is based at Carnegie-Mellon University. For more information, contact Jeff Peterson, jeff@cmbr.phys.cmu.edu .