6 research outputs found
A Bayesian method for the analysis of the dust emission in the Far-Infrared and Submillimeter
We present a method, based on Bayesian statistics, to fit the dust emission parameters in the far-infrared and submillimeter wavelengths. The method estimates the dust temperature and spectral emissivity index, plus their relationship, properly taking into account the statistical and systematic uncertainties. We test it on three sets of simulated sources detectable by the Herschel Space Observatory in the PACS and SPIRE spectral bands (70-500 ÎĽm), spanning over a wide range of dust temperatures. The simulated observations are a one-component interstellar medium and two two-component sources, both warm (H II regions) and cold (cold clumps (CCs)). We first define a procedure to identify the better model, then we recover the parameters of the model and measure their physical correlations by means of a Markov Chain Monte Carlo algorithm adopting multi-variate Gaussian priors. In this process, we assess the reliability of the model recovery and of parameter estimation. We conclude that the model and parameters are properly recovered only under certain circumstances and that false models may be derived in some cases. We applied the method to a set of 91 starless CCs in an interarm region of the Galactic plane with low star formation activity, observed by Herschel in the Hi-GAL survey. Our results are consistent with a temperature-independent spectral index
QUBIC: The Q and U bolometric interferometer for cosmology
The Q & U Bolometric Interferometer for Cosmology, QUBIC, is an innovative
experiment designed to measure the polarization of the Cosmic Microwave Background and
in particular the signature left therein by the inflationary expansion of the Universe. The
expected signal is extremely faint, thus extreme sensitivity and systematic control are necessary in order to attempt this measurement. QUBIC addresses these requirements using an
innovative approach combining the sensitivity of Transition Edge Sensor cryogenic bolometers, with the deep control of systematics characteristic of interferometers. This makes
QUBIC unique with respect to others classical imagers experiments devoted to the CMB
polarization. In this contribution we report a description of the QUBIC instrument including
recent achievements and the demonstration of the bolometric interferometry performed in
lab. QUBIC will be deployed at the observation site in Alto Chorrillos, in Argentina at the
end of 2019