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The Atacama Large millimetre/submillimetre Array (ALMA) makes use of water vapour radiometers (WVR), which monitor the atmospheric water vapour line at 183 GHz along the line of sight above each antenna to correct for phase delays…

Instrumentation and Methods for Astrophysics · Physics 2017-09-20 L. T. Maud , R. P. J. Tilanus , T. A. van Kempen , M. R. Hogerheijde , M. Schmalzl , I. Yoon , Y. Contreras , M. C. Toribio , Y. Asaki , W. R. F. Dent , E. Fomalont , S. Matsushita

Fluctuating properties of the atmosphere, and in particular its water vapour content, give rise to phase fluctuations of astronomical signals which, if uncorrected, lead to rapid deterioration of performance of (sub)-mm interferometers on…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Bojan Nikolic , Rosie C. Bolton , Sarah F. Graves , Richard E. Hills , John S. Richer

Atacama Large Millimeter/submillimeter Array (ALMA) will be the world largest mm/submm interferometer, and currently the Early Science is ongoing, together with the commissioning and science verification (CSV). Here we present a study of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 S. Matsushita , K. -I. Morita , D. Barkats , R. E. Hills , E. Fomalont , B. Nikolic

By observing bright and compact astronomical sources while also taking data with the 183 GHz Water Vapour Radiometers, ALMA will be able to measure the `empirical' relationship between fluctuations in the phase of the astronomical signal…

Instrumentation and Methods for Astrophysics · Physics 2009-07-28 Bojan Nikolic

We have developed Water Vapour Radiometers (WVRs) for the Australia Telescope Compact Array (ATCA) that are capable of determining signal path length fluctuations by virtue of measuring small temperature fluctuations in the atmosphere using…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Balthasar T. Indermuehle , Michael G. Burton , Jonathan Crofts

This memo describes the software engineering and technical details of the design and implementation of the wvrgcal program and associated libraries. This program performs off-line correction of atmospheric phase fluctuations in ALMA…

Instrumentation and Methods for Astrophysics · Physics 2012-07-26 Bojan Nikolic , Sarah F. Graves , Rosie C. Bolton , John S. Richer

We present the phase characteristics study of the Atacama Large Millimeter/submillimeter Array (ALMA) long (up to 3 km) baseline, which is the longest baseline tested so far using ALMA. The data consist of long time-scale (10 - 20 minutes)…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Satoki Matsushita , Yoshiharu Asaki , Ryohei Kawabe , Ed Fomalont , Denis Barkats , Stuartt Corder

We report on laboratory test results of the Compact Water Vapor Radiometer (CWVR) prototype for the NSF's Karl G. Jansky Very Large Array (VLA), a five-channel design centered around the 22 GHz water vapor line. Fluctuations in precipitable…

Instrumentation and Methods for Astrophysics · Physics 2019-08-20 Ajay Gill , Robert J. Selina , Bryan J. Butler

A diverse array of science goals require accurate flux calibration of observations with the Atacama Large Millimeter/Submillimeter array (ALMA), however, this goal remains challenging due to the stochastic time-variability of the ``grid''…

Instrumentation and Methods for Astrophysics · Physics 2020-11-25 Logan Francis , Doug Johnstone , Gregory Herczeg , Todd R. Hunter , Daniel Harsono

In a radio interferometer, the determination of geometrical antenna positions relies on accurate calibration of the dry and wet delay of the atmosphere above each antenna. For the Atacama Large Millimeter/Submillimeter Array (ALMA), which…

Instrumentation and Methods for Astrophysics · Physics 2016-10-14 Todd R. Hunter , Robert Lucas , Dominique Broguiere , Ed B. Fomalont , William R. F. Dent , Neil Phillips , David Rabanus , Catherine Vlahakis

This paper presents the first detailed investigation of the characteristics of mm/submm phase fluctuation and phase correction methods obtained using ALMA with baseline lengths up to ~15 km. Most of the spatial structure functions (SSFs)…

The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels…

Instrumentation and Methods for Astrophysics · Physics 2016-12-14 D. Defrère , P. Hinz , E. Downey , M. Böhm , W. C. Danchi , O. Durney , S. Ertel , J. M. Hill , W. F. Hoffmann , B. Mennesson , R. Millan-Gabet , M. Montoya , J. -U. Pott , A. Skemer , E. Spalding , J. Stone , A. Vaz

The success of any ALMA phase-calibration strategy, which incorporates phase transfer, depends on a good understanding of how the atmospheric path delay changes with frequency (e.g. Holdaway & Pardo 2001). We explore how the wet dispersive…

Instrumentation and Methods for Astrophysics · Physics 2009-12-16 Emily I. Curtis , Bojan Nikolic , John S. Richer , Juan R. Pardo

By direct measurements of the gas temperature, the Atacama Large Millimeter/sub-millimeter Array (ALMA) has yielded a new diagnostic tool to study the solar chromosphere. Here we present an overview of the brightness-temperature…

Atmospheric water vapor causes significant undesired phase fluctuations for the Submillimeter Array (SMA) interferometer, particularly in its highest frequency observing band of 690 GHz. One proposed solution to this atmospheric effect is…

Astrophysics · Physics 2007-05-23 D. Y. Kubo , T. R. Hunter , R. D. Christensen , P. I. Yamaguchi

Traditional color and airmass corrections can typically achieve ~0.02 mag precision in photometric observing conditions. A major limiting factor is the variability in atmospheric throughput, which changes on timescales of less than a night.…

Instrumentation and Methods for Astrophysics · Physics 2013-02-26 Ting Li , D. L. DePoy , R. Kessler , D. L. Burke , J. L. Marshall , J. Wise , J. -P. Rheault , D. W. Carona , S. Boada , T. Prochaska , R. Allen

Millimeter-wave remote sensing technology can significantly improve measurements of volcanic eruptions, yielding new insights into eruption processes and improving forecasts of drifting volcanic ash for aviation safety. Radiometers can…

The intensity of radiation at millimeter wavelengths from the solar atmosphere is closely related to the plasma temperature and the height of formation of the radiation is wavelength dependent. From that follows that the slope of the…

Solar and Stellar Astrophysics · Physics 2023-01-18 Henrik Eklund , Mikolaj Szydlarski , Sven Wedemeyer

Further analysis has been made on the millimeter and submillimeter-wave (100-1600 GHz or 3 mm - 188 micron) atmospheric opacity data taken with the Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above sea level in northern…

Astrophysics · Physics 2015-06-24 Satoki Matsushita , Hiroshi Matsuo

The Atacama Large Millimeter/submillimeter Array (ALMA) offers new diagnostic capabilities for studying the Sun, providing complementary insights through high spatial and temporal resolution at millimeter wavelengths. ALMA acts as a linear…

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