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Hamilton J-Ch, Charlassier R, Cressiot C, Kaplan J, Piat M, Rosset C, . (2008). Sensitivity of a bolometric interferometer to the cosmic microwave backgroud power spectrum
. A&A, 491(3), 923–927.
Abstract: Context. The search for B-mode polarization fluctuations in the Cosmic Microwave Background is one of the main challenges of modern cosmology. The expected level of the B-mode signal is very low and therefore requires the development of highly sensitive instruments with low systematic errors. An appealing possibility is bolometric interferometry. Aims. We compare in this article the sensitivity on the CMB angular power spectrum achieved with direct imaging, heterodyne and bolometric interferometry. Methods. Using a simple power spectrum estimator, we calculate its variance leading to the counterpart for bolometric interferometry of the well known Knox formula for direct imaging. Results. We find that bolometric interferometry is less sensitive than direct imaging. However, as expected, it is finally more sensitive than heterodyne interferometry due to the low noise of the bolometers. It therefore appears as an alternative to direct imagers with different and possibly lower systematic errors, mainly due to the absence of an optical setup in front of the horns.
Programme: 915
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. (2009). Bachelor's thesis, , .
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. (2009). QUBIC: the Q&U Bolometric Interferometer for Cosmology. JOURNAL OF LOW TEMPERATURE PHYSICS, 167(5-6), 872–878.
Abstract: The primordial B-mode polarisation of the Cosmic Microwave Background is the imprints of the gravitational wave background generated by inflation. Observing the B-mode is up to now the most direct way to constrain the physics of the primordial Universe, especially inflation. To detect these B-modes, high sensitivity is required as well as an exquisite control of systematics effects. To comply with these requirements, we propose a new instrument called QUBIC (Q and U Bolometric Interferometer for Cosmology) based on bolometric interferometry. The control of systematics is obtained with a close-packed interferometer while bolometers cooled to very low temperature allow for high sensitivity. We present the architecture of this new instrument, the status of the project and the self-calibration technique which allows accurate measurement of the instrumental systematic effects.
Programme: 915
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R. Charlassier, E.F. Bunn, J.-Ch. Hamilton, J. Kaplan, S. Malu. (2010). Bandwidth in bolometric interferometry.
. ASTRONOMY & ASTROPHYSICS, 514.
Abstract: Context. Bolometric interferometry is a promising new technology with potential applications to the detection of B-mode polarization fluctuations of the cosmic microwave background (CMB). A bolometric interferometer will have to take advantage of the wide spectral detection band of its bolometers to be competitive with imaging experiments. A crucial concern is that interferometers are assumed to be significantly affected by a spoiling effect known as bandwidth smearing. Aims: We investigate how the bandwidth modifies the work principle of a bolometric interferometer and affects its sensitivity to the CMB angular power spectra. Methods: We obtain analytical expressions for the broadband visibilities measured by broadband heterodyne and bolometric interferometers. We investigate how the visibilities must be reconstructed in a broadband bolometric interferometer and show that this critically depends on hardware properties of the modulation phase shifters. If the phase shifters produce shifts that are constant with respect to frequency, the instrument works like its monochromatic version (the modulation matrix is not modified), while if they vary (linearly or otherwise) with respect to frequency, one has to perform a special reconstruction scheme, which allows the visibilities to be reconstructed in frequency subbands. Using an angular power spectrum estimator that accounts for the bandwidth, we finally calculate the sensitivity of a broadband bolometric interferometer. A numerical simulation is performed that confirms the analytical results. Results: We conclude that (i) broadband bolometric interferometers allow broadband visibilities to be reconstructed regardless of the type of phase shifters used and (ii) for dedicated B-mode bolometric interferometers, the sensitivity loss caused by bandwidth smearing is quite acceptable, even for wideband instruments (a factor of 2 loss for a typical 20% bandwidth experiment).
Programme: 915
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. (2013). Quality Assessment of the First Measurements of Tropospheric Water Vapor and Temperature by the HAMSTRAD Radiometer Over Concordia Station, Antarctica
. 0196-2892, PP(99), 1–23.
Keywords: Extraterrestrial measurements, Instruments, Microwave radiometry, Ocean temperature, Temperature measurement, Terrestrial atmosphere, Water, Antarctica, atmospheric measurements, humidity measurements, least squares methods, microwave measurements, microwave radiometry, temperature measurements, time series analysis,
Programme: 910,1013
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. (2011). Bachelor's thesis, , .
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. (2011). Foraging habitats of top predators, and areas of ecological significance, on the Kerguelen Plateau. Bachelor's thesis, , .
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Cotte C., Delord K, Peron C., Bost C.a., Duhamel G., Pruvost P., Gasco N., Martin A., Weimerskirch H. (2011). Interactions between seabirds and fisheries in the French EEZs: implications for conservation and management. Bachelor's thesis, , .
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Dragon A.c., Marchand S., Authier M., Cotte C., Blain S., Guinet C. (2011). Insights into the spatio-temporal productivity distribution in the Indian Sector of the Southern Ocean provided by satellite observations. Bachelor's thesis, , .
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Martin C, Bentaleb I, Steelandt S, Guinet C, . (2011). Stable carbon and nitrogen isotope variations in canine dentine growth layers of Kerguelen southern elephant seals. 0171-8630, 439, 295–305.
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