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Polarization of radio emission in extragalactic jets at a sub-milliarcsecond angular resolution holds important clues for understanding the structure of the magnetic field in the inner regions of the jets and in close vicinity of the…

We present a novel Bayesian model and a corresponding robust, probabilistic calibration procedure for the CORSAIR polarimeter that can be applied to other polarimeters. Our calibration procedure combines existing Mueller matrix…

Solar and Stellar Astrophysics · Physics 2026-05-28 Alan Hsu , Jenna Samra , Steven Tomczyk , Maxim Kramar

We describe the design of a correlator system for ground and space-based VLBI. The correlator contains unique signal processing functions: flexible LO frequency switching for bandwidth synthesis; 1 ms dump intervals, multi-rate digital…

The Planck Low Frequency Instrument will recover polarization by differencing the outputs from radiometers sensitive to orthogonal polarizations. We contrast the systematic errors that afflict such a system with those that affect…

Astrophysics · Physics 2014-10-13 J. P. Leahy , V. Yurchenko , Morag Hastie , M. Bersanelli , N. Mandolesi

Optical polarimetry provides information on the geometry of the emitting region, the magnetic field configuration and the properties of dust in astrophysical sources. Current state-of-the-art instruments typically have a small field of view…

Black hole imaging challenges the 3rd generation space VLBI, the Very Long Baseline Interferometry, to operate on a 500 GHz band. The coherent integration time needed here is 450 s though the available space oscillators cannot offer more…

Instrumentation and Methods for Astrophysics · Physics 2021-09-20 V. Kudriashov , M. Martin-Neira , E. Lia , J. Michalski , P. Kant , D. Trofimowicz , M. Belloni , P. Jankovic , P. Waller , M. Brandt

The sub/millimeter wavelengths (86-690 GHz) very long baseline interferometry (VLBI) will provide $\sim5-40\ \mu$as angular resolution, $\sim10$ mJy baseline sensitivity, and $\sim 1\ \mu$as/yr proper motion precision, which can directly…

Astrophysics of Galaxies · Physics 2023-11-21 Shan-Shan Zhao , Wu Jiang , Ru-Sen Lu , Lei Huang , Zhi-Qiang Shen

We have assessed accuracy of estimates of Earth orientation parameters (EOP) determined from several very long baseline interferometry (VLBI) observing programs that ran concurrently at different networks. We consider that the root mean…

Geophysics · Physics 2026-03-09 Leonid Petrov , Christian Ploetz , Matthias Schartner

We present preliminary results from the deepest VLBI observations yet conducted. VLBA+GBT 1.4 GHz observations of a region within NOAO-N, reach an r.m.s. noise level of 9 microJy per beam. Three sources are clearly detected (> 7 sigma)…

Astrophysics · Physics 2009-11-07 M. A. Garrett , J. M. Wrobel , R. Morganti

A rigorous approach to simultaneously determine a Terrestrial Reference Frame (TRF) and Earth Orientation Parameters (EOP) is now currently applied on a routine basis in a coordinated project within the Groupe de Recherches de G\'eod\'esie…

Astrophysics · Physics 2008-12-18 G. Bourda , P. Charlot , R. Biancale

The new technique, multi-frequency imaging (MFI) is developed. In VLBI, Multi-Frequency Imaging (MFI) consists of multi-frequency synthesis (MFS) and multi-frequency analysis (MFA) of the VLBI data obtained from observations on various…

Astrophysics · Physics 2007-05-23 S. Likhachev

The high angular resolution and sensitivity of Very Long Baseline Interferometry (VLBI) offer a unique tool to identify and study active galactic nuclei and star-formation activity over cosmic time. However, despite recent technical…

Astrophysics of Galaxies · Physics 2024-12-05 Célestin Herbé-George , J. P. Mckean , Raffaella Morganti , Jack F. Radcliffe

High-speed polarization management is highly desirable for many applications, such as remote sensing, telecommunication, and medical diagnosis. However, most of the approaches for polarization management rely on bulky optical components…

Uncertainty in the calibration of gravitational-wave (GW) detector data leads to systematic errors which must be accounted for in setting limits on the strength of GW signals. When cross-correlation measurements are made using data from a…

General Relativity and Quantum Cosmology · Physics 2014-03-07 John T. Whelan , Emma L. Robinson , Joseph D. Romano , Eric H. Thrane

Instruments for radio astronomical observations have come a long way. While the first telescopes were based on very large dishes and 2-antenna interferometers, current instruments consist of dozens of steerable dishes, whereas future…

Instrumentation and Methods for Astrophysics · Physics 2015-03-13 Stefan J. Wijnholds , Sebastiaan van der Tol , Ronald Nijboer , Alle-Jan van der Veen

External effects such as shocks and temperature variations affect the calibration of visual-inertial sensor systems and thus they cannot fully rely on factory calibrations. Re-calibrations performed on short user-collected datasets might…

Robotics · Computer Science 2019-01-23 Thomas Schneider , Mingyang Li , Cesar Cadena , Juan Nieto , Roland Siegwart

States of light encoding multiple polarizations - vector beams - offer unique capabilities in metrology and communication. However, their practical application is limited by the lack of methods for measuring many polarizations in a scalable…

Optics · Physics 2022-09-13 Davide Pierangeli , Claudio Conti

Context: Radio astronomical receivers are now expanding their frequency range to cover large (octave) fractional bandwidths for sensitivity and spectral flexibility, which makes the design of good analogue circular polarizers challenging.…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Koyel Das , A. L. Roy , R. Keller , G. Tuccari

In this paper, a new geometry index of Very Long Baseline Interferometry (VLBI) observing networks, the volume of network $V$, is examined as an indicator of the errors in the Earth orientation parameters (EOP) obtained from VLBI…

Geophysics · Physics 2009-08-14 Zinovy Malkin

We report on a recent 90 cm wide-field VLBI survey of two 3.1 deg^2 fields using the VLBA, Westerbork and Jodrell Bank telescopes. In-beam calibration was used to calibrate each field, the process was simplified by imaging the calibrators…

Astrophysics · Physics 2007-05-23 Emil Lenc , Mike A. Garrett , Olaf Wucknitz , James M. Anderson , Steven J. Tingay
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