33 research outputs found
The Antarctic Submillimeter Telescope and Remote Observatory (AST/RO)
AST/RO, a 1.7 m diameter telescope for astronomy and aeronomy studies at
wavelengths between 200 and 2000 microns, was installed at the South Pole
during the 1994-1995 Austral summer. The telescope operates continuously
through the Austral winter, and is being used primarily for spectroscopic
studies of neutral atomic carbon and carbon monoxide in the interstellar medium
of the Milky Way and the Magellanic Clouds. The South Pole environment is
unique among observatory sites for unusually low wind speeds, low absolute
humidity, and the consistent clarity of the submillimeter sky. Four heterodyne
receivers, an array receiver, three acousto-optical spectrometers, and an array
spectrometer are installed. A Fabry-Perot spectrometer using a bolometric array
and a Terahertz receiver are in development. Telescope pointing, focus, and
calibration methods as well as the unique working environment and logistical
requirements of the South Pole are described.Comment: 57 pages, 15 figures. Submitted to PAS
Detection chain and electronic readout of the QUBIC instrument
The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10⁻¹⁶ W/√Hz
Detection chain and electronic readout of the QUBIC instrument
The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10⁻¹⁶ W/√Hz
Planck Early Results: Statistical properties of extragalactic radio sources in the Planck Early Release Compact Source Catalogue
The data reported in Planck's Early Release Compact Source Catalogue (ERCSC)
are exploited to measure the number counts (dN/dS) of extragalactic radio
sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the
catalogue, this measurement extends to the rarest and brightest sources in the
sky. At lower frequencies (30, 44, and 70 GHz) our counts are in very good
agreement with estimates based on WMAP data, being somewhat deeper at 30 and 70
GHz, and somewhat shallower at 44 GHz. Planck's source counts at 143 and 217
GHz join smoothly with the fainter ones provided by the SPT and ACT surveys
over small fractions of the sky. An analysis of source spectra, exploiting
Planck's uniquely broad spectral coverage, finds clear evidence of a steepening
of the mean spectral index above about 70 GHz. This implies that, at these
frequencies, the contamination of the CMB power spectrum by radio sources below
the detection limit is significantly lower than previously estimated.Comment: Planck Collaboration 2011i, A&A accepted, 11 pages, 7 figure
Light-response in two clonal strains of the haptophyte Tisochrysis lutea: Evidence for different photoprotection strategies
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