Measurement of polarization with the Degree Angular Scale Interferometer

Abstract

Measurements of the cosmic microwave background (CMB) radiation can reveal with remarkable precision the conditions of the Universe when it was 400,000 years old. The three most fundamental properties of the CMB are its frequency spectrum (which determines the temperature), and the fluctuations in both the temperature and polarization across a range of angular scales. The frequency spectrum has been well determined, and considerable progress has been made in measuring the power spectrum of the temperature fluctuations. But despite many efforts to measure the polarization, detection of this property of the CMB has hitherto been beyond the reach of even the most sensitive observations. Here we describe the Degree Angular Scale Interferometer (DASI), an array of radio telescopes, which for the past two years has conducted polarization-sensitive observations of the CMB from the Amundsen–Scott South Pole research station.

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Figure 1: Comparison of the instrumental polarization for single and multi-element polarizers.
Figure 2: Ground shield geometry.
Figure 3: DASI absolute phase offsets.
Figure 4: DASI off-axis leakage measurements.
Figure 5: DASI image of the Moon.
Figure 6: Observations of the molecular cloud complex NGC6334.
Figure 7: Polarization field locations.
Figure 8: Total intensity maps of the differenced (C2–C3) CMB fields.

References

  1. 1

    Leitch, E. M. et al. Experiment design and first season observations with the Degree Angular Scale Interferometer. Astrophys. J. 568, 28–37 (2002)

    ADS  Article  Google Scholar 

  2. 2

    Halverson, N. W. et al. Degree Angular Scale Interferometer first results: A measurement of the cosmic microwave background angular power spectrum. Astrophys. J. 568, 38–45 (2002)

    ADS  Article  Google Scholar 

  3. 3

    Pryke, C. et al. Cosmological parameter extraction from the first season of observations with the Degree Angular Scale Interferometer. Astrophys. J. 568, 46–51 (2002)

    ADS  Article  Google Scholar 

  4. 4

    Kovac, J. M. et al. Detection of polarization in the cosmic microwave background using DASI. Nature 420, 772–787 (2002)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Padin, S. et al. The Cosmic Background Imager. Publ. Astron. Soc. Pacif. 114, 83–97 (2002)

    ADS  Article  Google Scholar 

  6. 6

    Kamionkowski, M., Kosowsky, A. & Stebbins, A. Statistics of cosmic microwave background polarization. Phys. Rev. D 55, 7368–7388 (1997)

    ADS  CAS  Article  Google Scholar 

  7. 7

    Zaldarriaga, M. & Seljak, U. All-sky analysis of polarization in the microwave background. Phys. Rev. D 55, 1830–1840 (1997)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Hu, W. & White, M. A CMB polarization primer. New Astron. 2, 323–344 (1997)

    ADS  Article  Google Scholar 

  9. 9

    Moffat, P. H. Aperture synthesis polarimetry of the moon at 21 cm. Mon. Not. R. Astron. Soc. 160, 139–154 (1972)

    ADS  Article  Google Scholar 

  10. 10

    Mitchell, D. I. & De Pater, I. Microwave imaging of Mercury's thermal emission at wavelengths from 0.3 to 20.5 cm. Icarus 110, 2–32 (1994)

    ADS  Article  Google Scholar 

  11. 11

    Poppi, S., Carretti, E., Cortiglioni, S., Krotikov, V. D. & Vinyajkin, E. N. AIP Conf. Proc. 609, Astrophysical Polarized Backgrounds (eds Cecchini, S., Cortiglioni, S., Sault, R. & Sbarra, C.) 187–192 (AIP, Melville, New York, 2002)

    Google Scholar 

  12. 12

    Burton, M. G. et al. High-resolution imaging of photodissociation regions in NGC 6334. Astrophys. J. 542, 359–366 (2000)

    ADS  CAS  Article  Google Scholar 

  13. 13

    Jackson, J. M. & Kraemer, K. E. Photodissociation regions and HII regions in NGC 6334. Astrophys. J. 512, 260–270 (1999)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Högbom, J. A. Aperture synthesis with a non-regular distribution of interferometer baselines. Astron. Astrophys. Suppl. 15, 417–426 (1974)

    ADS  Google Scholar 

  15. 15

    Haslam, C. G. T. et al. A 408 MHz all-sky continuum survey. I—observations at southern declinations and for the north polar region. Astron. Astrophys. 100, 209–219 (1981)

    ADS  CAS  Google Scholar 

  16. 16

    Padin, S., Cartwright, J. K., Shepherd, M. C., Yamasaki, J. K. & Holzapfel, W. L. A wideband analog correlator for microwave background observation. IEEE Trans. Instrum. Meas. 50, 1234–1240 (2001)

    ADS  Article  Google Scholar 

  17. 17

    Wright, A. E., Griffith, M. R., Burke, B. F. & Ekers, R. D. The Parkes-MIT-NRAO (PMN) surveys. 2: Source catalog for the southern survey (- 87.5° < δ < -37°). Astrophys J. Suppl. 91, 111–308 (1994)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We are indebted to the Caltech CBI team led by T. Readhead, in particular to S. Padin for a considerable fraction of DASI's electronics design, to J. Cartwright for the downconverter design and to M. Shepherd for data acquisition software. E. Chauvin of Vertex/RSI is thanked for professional excellence in the design and delivery of the telescope mount. We thank Raytheon Polar Services for their support of the DASI project, including the erection of the DASI ground shields, and in particular R. Rowatt and his crew. We are indebted to the Center for Astrophysical Research in Antarctica (CARA), in particular the efforts of A. Day, S. Meyer, N. Odalen, R., D. and E. Pernic, R. Lowenstein, R. Spotz, M. Whitehead and the CARA polar operations staff. We thank J. Kooi for his assistance with the installation of the polarization hardware, J. Yamasaki for help with electronics, E. LaRue and G. Drag for the assembly of the calibration wire grids, M. Loh for assistance with the Sun shield and K. Coble for analysis of DASI primary beam measurements. We thank the TopHat collaboration for the use of their Sun shield. We thank the observatory staff of the Australia Telescope Compact Array, in particular B. Sault and R. Subrahmanyan, for their generosity in providing point source observations of the DASI fields. This research was initially supported by the National Science Foundation (NSF) under a cooperative agreement with CARA, a NSF Science and Technology Center; it is currently supported by the NSF-OPP. J.E.C. acknowledges support from the James S. McDonnell Foundation and the David and Lucile Packard Foundation. J.E.C. and C.P. acknowledge support from the Center for Cosmological Physics.

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Leitch, E., Kovac, J., Pryke, C. et al. Measurement of polarization with the Degree Angular Scale Interferometer. Nature 420, 763–771 (2002). https://doi.org/10.1038/nature01271

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