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Polarization observations of the cosmic microwave background with the Cosmic Background Imager from September 2002 to May 2004 provide a significant detection of the E-mode polarization and reveal an angular power spectrum of polarized emission showing peaks and valleys that are shifted in phase by half a cycle relative to those of the total intensity(More)
– 2 – Using the Cosmic Background Imager, a 13-element interferometer array operating in the 26–36 GHz frequency band, we have observed 40 deg 2 of sky in three pairs of fields, each ∼ 145 ′ × 165 ′ , using overlapping pointings (mosaicing). We present images and power spectra of the cosmic microwave background radiation in these mosaic fields. We remove(More)
The formation of gaseous giant planets is thought to occur in the first few million years after stellar birth. Models predict that the process produces a deep gap in the dust component (shallower in the gas). Infrared observations of the disk around the young star HD 142527 (at a distance of about 140 parsecs from Earth) found an inner disk about 10(More)
We report measurements of anisotropy in the cosmic microwave background radiation over the multipole range ℓ ∼ 200 → 3500 with the Cosmic Background Imager – 2 – based on deep observations of three fields. These results confirm the drop in power with increasing ℓ first reported in earlier measurements with this instrument, and extend the observations of(More)
The spectral energy distribution of the dark cloud LDN 1622, as measured by Finkbeiner using WMAP data, drops above 30 GHz and is suggestive of a Boltzmann cutoff in grain rotation frequencies, characteristic of spinning dust emission. LDN 1622 is conspicuous in the 31 GHz image we obtained with the Cosmic Background Imager, which is the first cm-wave(More)
The maximum entropy method (MEM) is a well known deconvolution technique in radio-interferometry. This method solves a non-linear optimization problem with an entropy regularization term. Other heuristics such as CLEAN are faster but highly user dependent. Nevertheless, MEM has the following advantages: it is unsupervised, it has an statistical basis, it(More)
A snow-line is the region of a protoplanetary disk at which a major volatile, such as water or carbon monoxide, reaches its condensation temperature. Snow-lines play a crucial role in disk evolution by promoting the rapid growth of ice-covered grains. Signatures of the carbon monoxide snow-line (at temperatures of around 20 kelvin) have recently been imaged(More)
ALMA is a revolutionary instrument in its scientific concept, its engineering design and its organisation as a global effort. ALMA and new incoming radio-telescopes delivery big amounts of data that are useful to the sky image reconstruction. In this context, MEM is one of the most recognized reconstruction algorithms in radio-interferometry and is based on(More)
Many stars are surrounded by disks of dusty debris formed in the collisions of asteroids, comets, and dwarf planets, but is gas also released in such events? Observations at submillimeter wavelengths of the archetypal debris disk around β Pictoris show that 0.3% of a Moon mass of carbon monoxide orbits in its debris belt. The gas distribution is highly(More)
The advent of high fidelity observatory interferometers such ALMA, invites new opportunities in algorithmic research for image processing. Interferometer telescopes perform irregular sampling on the Fourier transform of the sky images called "visibilities." The inverse problem resolution is called "Image Synthesis". This inverse problem is "Ill-posed" and(More)