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Related papers: On accuracy assessment of celestial reference fram…

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From 43GHz VLBA observations of the pair of radio sources 1928+738 and 2007+777 we have demonstrated the feasibility of precision phase-delay differential astrometric techniques at millimeter wavelengths. For a pair of sources with 5…

Astrophysics · Physics 2007-05-23 J. C. Guirado , J. M. Marcaide , M. A. Perez-Torres , E. Ros

Context: The Deep Extragalactic VLBI-Optical Survey (DEVOS) aims at constructing a large sample of compact radio sources up to two orders of magnitude fainter than those studied in other Very Long Baseline Interferometry (VLBI) surveys.…

Astrophysics · Physics 2008-01-09 S. Frey , L. I. Gurvits , Z. Paragi , L. Mosoni , M. A. Garrett , S. T. Garrington

The third realization of the International Celestial Reference Frame (ICRF3) was adopted in August 2018 and includes positions of extragalactic objects at three frequencies: 8.4 GHz, 24 GHz, and 32 GHz. In this paper, we present celestial…

Instrumentation and Methods for Astrophysics · Physics 2024-04-30 Hana Krasna , David Gordon , Aletha de Witt , Christopher S. Jacobs

Carrier frequency offset estimation (CFOE) is a critical stage in modern coherent optical communication systems. Although conventional all-digital techniques perform reliably in typical fiber-optic communication links, CFOE often becomes a…

Signal Processing · Electrical Eng. & Systems 2026-03-31 I. P. Vieira , G. V. Serra , R. A. Colares , D. A. A. Mello

Context. The current algorithms used for the calibration and analysis of very long baseline interferometry (VLBI) networks that only use linear polarizers (as is the case of the VLBI Global Observing System, VGOS) do not properly account…

Instrumentation and Methods for Astrophysics · Physics 2024-06-19 V. Pérez-Díez , I. Martí-Vidal , E. Albentosa-Ruiz , J. González-García , F. Jaron , T. Savolainen , M. H. Xu , R. Bachiller

As dense low Earth orbit (LEO) constellations are being planned, the need for accurate synchronization schemes in high-speed environments remains a challenging problem to tackle. To further improve synchronization accuracy in channeling…

Signal Processing · Electrical Eng. & Systems 2022-10-04 Rıfat Volkan Şenyuva , Güneş Karabulut Kurt

The light from a source at a distance d will arrive at detectors separated by 100 AU at times that differ by as much as 120 (d/100 Mpc)^{-1} nanoseconds because of the curvature of the wavefront. At gigahertz frequencies, the arrival time…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-10 Kyle Boone , Matthew McQuinn

The polarization properties of radio sources at very low frequencies (<200 MHz) have not been widely measured, but the new generation of low-frequency radio telescopes, including the Low Frequency Array (LOFAR: a Square Kilometre Array Low…

We introduce a new cross-correlation method to detect and verify the astrophysical origin of Faraday Rotation (FR) in multiwavelength surveys. FR is well studied in radio astronomy from radio point sources but the $\lambda^{2}$ suppression…

Instrumentation and Methods for Astrophysics · Physics 2018-01-18 Matthew Kolopanis , Philip Mauskopf , Judd Bowman

Reverberation chambers (RCs) were recently reported as a low-cost alternative to anechoic chambers (ACs) to perform radar cross-section (RCS) pattern measurements. The method consists of using transmitting and receiving antennas pointing…

Though in-orbit calibration is adopted to reduce position error of individual star spot down to 0.02pixel on star tracker, little study has been conducted on the accuracy to what extent for some significant error sources which often leads…

Instrumentation and Methods for Astrophysics · Physics 2020-10-21 J. Zhang , Y. C. Hao , L. Wang , Y. Long

Recently, Owen(1993) and Owen and Ledlow (1994) have shown that the dividing line between Fanaroff-Riley class~I and class~II Radio Sources is very sharp when the sources are represented as points in the radio-optical luminosity plane. It…

Astrophysics · Physics 2016-08-30 Geoffrey V. Bicknell

We have observed 37 bright, polarized radio sources with the Allen Telescope Array (ATA) to present a novel analysis of their Faraday rotation properties. Each source was observed during the commissioning phase with 2 to 4 100-MHz bands at…

Many low-luminosity active galactic nuclei (AGNs) contain a compact radio core which can be observed with high angular resolution using very long baseline interferometry (VLBI). Combining arcsec-scale structural information with…

Astrophysics of Galaxies · Physics 2020-04-06 Máté Krezinger , Sándor Frey , Zsolt Paragi , Roger Deane

A complete sample of bright ROSAT sources with hard XRB-like spectra in the Galactic Plane (|b| < 15 deg.) has been tentatively identified with radio sources in the GB6/PMN/NVSS surveys, and subsequently observed with the Australia…

Astrophysics · Physics 2007-05-23 G. S. Tsarevsky , E. P. Pavlenko , R. A. Stathakis , N. S. Kardashev , O. B. Slee

We propose to use degree-scale angular clustering of fast radio bursts (FRBs) to identify their origin and the host galaxy population. We study the information content in autocorrelation of the angular positions and dispersion measures (DM)…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-03 Masato Shirasaki , Kazumi Kashiyama , Naoki Yoshida

Compact Symmetric Objects (CSOs) are small (less than 1 kpc) radio sources which have symmetric double lobes or jets. The dominant theory for the small size of these objects is that they are young radio sources which could grow into larger…

Astrophysics of Galaxies · Physics 2010-11-11 S. E. Tremblay , G. B. Taylor , J. F. Helmboldt , C. D. Fassnacht , R. W. Romani

In optical interferometry, the visibility squared modulus are generally assumed to follow a Gaussian distribution and to be independent of each other. A quantitative analysis of the relevance of such assumptions is important to help…

Instrumentation and Methods for Astrophysics · Physics 2014-05-15 Antony Schutz , Martin Vannier , David Mary , Andre Ferrari , Florentin Millour , Romain Petrov

Various studies have laid claim to finding an alignment of the polarization vectors or radio jets of active galactic nuclei (AGN) over large distances, but these results have proven controversial and so far, there is no clear explanation…

For finite length polar codes, channel polarization leaves a significant number of channels not fully polarized. Adding a Cyclic Redundancy Check (CRC) to better protect information on the semi-polarized channels has already been…

Information Theory · Computer Science 2016-11-14 A. Elkelesh , M. Ebada , S. Cammerer , S. ten Brink