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| − | <big>'''"TianLai Project" Dark Energy Observation'''</big> | + | <big>The TianLai Project -- A Dark Energy Radio Observation Experiment<big> |
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| − | A wide range of cosmological observations have been proposed that make use of the 21 cm emission of neutral hydrogen. These include: Measurement of the expansion history h(z), via the mapping of large scale structure and baryon acoustic oscillations at redshifts from 0 to 1; Detection of the redshift of the Epoch of Reionization, believed to lie someplace in the redshift range 7 to 12; and Measurement of the linear growth of large scale structure in the neutral dark age at redshifts as high as 50. Because 21 cm observations provide three-dimensional information many theorists are intrigued by the huge information content such observations promise to provide. The physics examined by such observations may soon include a test of the “Dark Energy” equation of state, and study of linear growth of dark matter structures via ordinary attractive gravity, as well as information from very early epochs on star formation and radiative transport.
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| − | But, even though the potential for such observation is exciting, the actual observations remain challenging to carry out. First, the telescopes are big. These observations will be made using telescopes of collecting area at least 10,000 m^2, and with hundreds or even thousands of wide-band receiver channels. Second, both Galactic and extragalactic foreground emissions exceed the sought after 21 cm signals by many orders of magnitude. Third, the frequency range of these observations is heavily contaminated by man-made interference. Removal of these foregrounds, and the man made interference, will require understanding and calibration of the telescope response with unprecedented precision.
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| | + | The neutral hydrogen atoms in the Universe radiates with a wavelength of 21 cm, on large scales the intensity of this radiation is proportional to the matter density. By radio observation, one can probe the cosmic large scale structure distribution. Using the baryon acoustic oscillation signatures in the matter power spectrum as standard rulers, high precision cosmological measurements can be obtained, and the dark energy equation of state parameter w measured. This provides an important tool for dark energy observation. |
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| | == Getting started == | | == Getting started == |
Revision as of 22:57, 17 July 2012
The TianLai Project -- A Dark Energy Radio Observation Experiment
The neutral hydrogen atoms in the Universe radiates with a wavelength of 21 cm, on large scales the intensity of this radiation is proportional to the matter density. By radio observation, one can probe the cosmic large scale structure distribution. Using the baryon acoustic oscillation signatures in the matter power spectrum as standard rulers, high precision cosmological measurements can be obtained, and the dark energy equation of state parameter w measured. This provides an important tool for dark energy observation.
Getting started
