5.3 Saskatoon5 Current and future CMB 5.1 The COBE satellite

5.2 The Tenerife experiments 

[Project collaborators: R. Davies (Jodrell Bank - Principal Investigator); R. Rebolo, C. Gutierrez, R. Watson, R. Hoyland (IAC, Tenerife); A. Lasenby, A. Jones, G. Rocha, S. Hancock (MRAO, Cambridge).]

A description of these experiments was given in Lasenby & Hancock [65]. Here we briefly summarise the relevant features. The Tenerife experiments constitute a suite of three instruments, working at 10, 15 and 33 GHz, designed and built at Jodrell Bank (Davies et al. 1992 [45], 1996 [44]) and operated by the IAC in-situ on Tenerife island. Data are taken by drift scanning in right ascension at fixed declination and by sampling at tex2html_wrap_inline1793 intervals in declination with a beamwidth of tex2html_wrap_inline1795 (FWHM) it is possible to build up a fully sampled two-dimensional map of the sky at each frequency [82]. Initially, observations were concentrated on the strip of sky at declination tex2html_wrap_inline1797 where the low frequency surveys of Haslam et al. (408 MHz) [55] and Reich and Reich (1420 MHz) [83] indicate a minimum in Galactic foreground emission.

Analysis of the data at declination tex2html_wrap_inline1797 has been made and reported in Hancock et al. (1994) [52Jump To The Next Citation Point In The Article]. Results from the Dec. tex2html_wrap_inline1801 data scans at 10 and 15 GHz have recently been reported in Gutierrez et al. [51] and are consistent with the Dec. tex2html_wrap_inline1803 data. A level of tex2html_wrap_inline1805   tex2html_wrap_inline1529 K was found in a high Galactic latitude region at Dec. tex2html_wrap_inline1801 at 15 GHz. The COBE data was used in Bunn et al. (1996) to make a prediction for the Tenerife data. The comparison between this prediction and the Tenerife 15 GHz data is shown in Figure  12, and it is seen that there is very good agreement with the main features in the COBE scan. This is evidence for features that are constant in amplitude over a frequency range of 15 GHz to 90 GHz and is a very strong candidate for a real CMB anisotropy.

  

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Figure 12: Comparison between the maximum entropy reconstruction of the Tenerife Dec. tex2html_wrap_inline1801 data at 15 GHz (solid line) and the COBE DMR predictions of Bunn et al. (1996) (dashed line) at 53 and 90 GHz.

The Tenerife programme is continuing, with the objective of mapping some 4000 square degrees of sky at 10, 15 and 33 GHz. In conjunction with the COBE four-year data set, these experiments will continue to offer a useful source of large-scale CMB anisotropy measurements and hence to directly probe cosmological theories. In terms of power spectrum results, a revised estimate of the fluctuation amplitude for tex2html_wrap_inline1617 values near tex2html_wrap_inline1815 has been constructed from the Dec tex2html_wrap_inline1803 data, making an allowance for an atmospheric contribution (Hancock et al. 1997 [53]) that was not subtracted in Hancock et al. [52]. This is used below in comparison with theoretical curves.

Preliminary analysis of the full 15 GHz data set (Dec. tex2html_wrap_inline1819 to tex2html_wrap_inline1821) has been made and will be presented in a future paper. For an assumed value of n =1 a full two dimensional likelihood analysis gives tex2html_wrap_inline1825   tex2html_wrap_inline1529 K.



5.3 Saskatoon5 Current and future CMB 5.1 The COBE satellite

image The Cosmic Microwave Background
Aled W. Jones and Anthony N. Lasenby
http://www.livingreviews.org/lrr-1998-11
© Max-Planck-Gesellschaft. ISSN 1433-8351
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