Showing papers on "Intensity mapping published in 2008"
TL;DR: In this paper, the authors show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping, which is the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.
Abstract: The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called "dark energy." To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 10(9) individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.
325 citations
TL;DR: The 21 cm line emission by residual cosmic hydrogen after reionization can be used to trace the power spectrum of density perturbations through a significant fraction of the observable volume of the universe as mentioned in this paper.
Abstract: Measurements of the 21 cm line emission by residual cosmic hydrogen after reionization can be used to trace the power spectrum of density perturbations through a significant fraction of the observable volume of the Universe. We show that a dedicated 21 cm observatory could probe a number of independent modes that is 2 orders of magnitude larger than currently available, and enable a cosmic-variance limited detection of the signature of a neutrino mass approximately 0.05 eV. The evolution of the linear growth factor with redshift could also constrain exotic theories of gravity or dark energy to an unprecedented precision.
170 citations
TL;DR: In this paper, the first statistically significant detection of cosmic structure using broadly distributed hydrogen radio emission was presented using a cross correlation with optical galaxies, achieving statistical noise levels of $20 \mu $K, unprecedented in this frequency band.
Abstract: We present the first statistically significant detection of cosmic structure using broadly distributed hydrogen radio emission. This is accomplished using a cross correlation with optical galaxies. Statistical noise levels of $20 \mu $K are achieved, unprecedented in this frequency band. This lends support to the idea that large volumes of the universe can be rapidly mapped without the need to resolve individual faint galaxies, enabling precise constraints to dark energy models. We discuss strategies for improved intensity mapping.
24 citations
01 Jan 2008
TL;DR: In this article, the intensity mapping method was specially designed to eliminate phase ambiguity and the maximum pressure obtained from fringe analysis is 0.33 atm correspond to radius of 2.738 mm and from intensity mapping was 0.244 atm corresponding to 2.526 mm.
Abstract: Pressure change due to laser interaction can be measured using fringe analysis method which is reliable and accurate but rather time-consuming and also by the intensity mapping method which is a very fast and efficient but quite often plagued with phase ambiguity. In this work, the intensity mapping method was specially designed to eliminate phase ambiguity. Both methods of analysis are based on Abel inversion technique. Initially fringe analysis was seem to be more reliable but by around 5 (is delays both methods seemed to reach an agreeable value. The maximum pressure obtained from fringe analysis is 0.33 atm correspond to radius of 2.738 mm and from intensity mapping method is 0.244 atm corresponding to 2.526 mm.
1 citations