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twentieth-century cosmologists. Photons from the CMB are detected today
in the millimetric and centimetric wavelength ranges as background radiation
in the microwave region of the spectrum with a temperature of 2.726 ± 0.004 K
using radio-astronomical techniques.
At the beginning of the eighties, the United Kingdom’s Jodrell Bank
Observatory (Nuffield Radio Astronomy Laboratories) told us they were
interested in setting up radio telescopes at Teide Observatory because of the
site’s special atmospheric conditions. We began negotiations and, in our usual
style, sent a resident astrophysicist, Jorge Sánchez, to England to carry out
research with them and learn about radio astronomy. We signed an agreement
with the University of Manchester, as a consequence of which three radiometers, by joint agreement designated the Tenerife Experiment, were set up to
measure CMB anisotropies in the frequency range 10–33 GHz, with an
angular resolution of 5 degrees. The Cavendish Laboratory of the University
of Cambridge joined the agreement, and in 1984 systematic observations of
the cosmic microwave background commenced. Jorge Sánchez later moved to
solar physics, and Rafael Rebolo took over the project. Since then, Teide
Observatory has hosted most of the European terrestrial experiments concerning CMB anisotropies, and Rafael Rebolo is now leading the IAC team in
this field.
In 1987 the first results from the Tenerife Experiment, placing more restrictive limits on CMB anisotropy, were published in Nature. IAC astrophysicists
were among the coauthors. This set of results provided the first independent
confirmation of the celebrated discovery of anisotropies in the CMB by the
Cosmic Background Explorer (COBE) satellite.
Between 1998 and 2008 we took on the challenge of designing and building the COSMOSOMAS (COSMOlogical Structures On Medium Angular
Scales) experiment to separate Galactic synchrotron emission from the CMB
and microwave emission from free–free interactions in the interstellar
medium. With a resolution of 1 degree, the instruments were designed to
observe in the frequency range between 10 and 20 GHz. The experiment was
located at Teide Observatory and comprised two sets of antennas with cryogenically cooled receivers operating at 11, 13, 15, and 17 GHz. The antennas
observed the sky in circular scans obtained using a flat mirror rotating at 60
revolutions per minute. The antennas concentrated the radiation into various
receivers housed in cryostats at a temperature of 20 K (–253 °C). Built entirely
at the IAC, the telescope produced hundreds of maps which, when combined,
reached a sensitivity of 50 μK at 1-degree angular scales at each frequency.
Even today, no experiment has surpassed this sensitivity and sky coverage at
these frequencies and angular scales.
F. Sánchez
twentieth-century cosmologists. Photons from the CMB are detected today
in the millimetric and centimetric wavelength ranges as background radiation
in the microwave region of the spectrum with a temperature of 2.726 ± 0.004 K
using radio-astronomical techniques.
At the beginning of the eighties, the United Kingdom’s Jodrell Bank
Observatory (Nuffield Radio Astronomy Laboratories) told us they were
interested in setting up radio telescopes at Teide Observatory because of the
site’s special atmospheric conditions. We began negotiations and, in our usual
style, sent a resident astrophysicist, Jorge Sánchez, to England to carry out
research with them and learn about radio astronomy. We signed an agreement
with the University of Manchester, as a consequence of which three radiometers, by joint agreement designated the Tenerife Experiment, were set up to
measure CMB anisotropies in the frequency range 10–33 GHz, with an
angular resolution of 5 degrees. The Cavendish Laboratory of the University
of Cambridge joined the agreement, and in 1984 systematic observations of
the cosmic microwave background commenced. Jorge Sánchez later moved to
solar physics, and Rafael Rebolo took over the project. Since then, Teide
Observatory has hosted most of the European terrestrial experiments concerning CMB anisotropies, and Rafael Rebolo is now leading the IAC team in
this field.
In 1987 the first results from the Tenerife Experiment, placing more restrictive limits on CMB anisotropy, were published in Nature. IAC astrophysicists
were among the coauthors. This set of results provided the first independent
confirmation of the celebrated discovery of anisotropies in the CMB by the
Cosmic Background Explorer (COBE) satellite.
Between 1998 and 2008 we took on the challenge of designing and building the COSMOSOMAS (COSMOlogical Structures On Medium Angular
Scales) experiment to separate Galactic synchrotron emission from the CMB
and microwave emission from free–free interactions in the interstellar
medium. With a resolution of 1 degree, the instruments were designed to
observe in the frequency range between 10 and 20 GHz. The experiment was
located at Teide Observatory and comprised two sets of antennas with cryogenically cooled receivers operating at 11, 13, 15, and 17 GHz. The antennas
observed the sky in circular scans obtained using a flat mirror rotating at 60
revolutions per minute. The antennas concentrated the radiation into various
receivers housed in cryostats at a temperature of 20 K (–253 °C). Built entirely
at the IAC, the telescope produced hundreds of maps which, when combined,
reached a sensitivity of 50 μK at 1-degree angular scales at each frequency.
Even today, no experiment has surpassed this sensitivity and sky coverage at
these frequencies and angular scales.
F. Sánchez