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The accuracy of astrometric observations conducted via a space-borne optical interferometer orbiting the Earth is expected to approach a few microarcseconds. Data processing of such extremely high-precision measurements requires access to a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Sergei M. Kopeikin , N. V. Shuygina , M. V. Vasilyev , E. I. Yagudina , L. I. Yagudin

We have used the Very Large Array (VLA), linked with the Pie Town Very Long Baseline Array antenna, to determine astrometric positions of 46 radio stars in the International Celestial Reference Frame (ICRF). Positions were obtained in the…

The radio observations are based on dual frequency Mark--III VLBI data from 1979 until the end of 1993. Currently 436 sources define the celestial inertial frame. A comparison to the JPL94R01 catalog is made. Position vs. time plots of…

Astrophysics · Physics 2007-05-23 N. Zacharias , A. L. Fey , J. L. Russell , K. J. Johnston

Faraday rotation measures (RMs) have been used for many studies of cosmic magnetism, and in most cases having more RMs is beneficial for those studies. This has lead to development of RM surveys that have produced large catalogs, as well as…

Polarization is very sensitive to the configuration of the magnetic field in the radiation region. In addition to polarization curve and polarization spectrum, studies of polarization angle (PA) rotation spectrum is also crucial. In this…

High Energy Astrophysical Phenomena · Physics 2025-10-15 Xing-Yao Wang , Jia-Sheng Li , Mi-Xiang Lan

The S-band Polarisation All Sky Survey (SPASS/ATCA) rotation measure (RM) catalogue is the largest broadband RM catalogue to date, increasing the RM density in the sparse southern sky. Through analysis of this catalogue, we report a…

Astrophysics of Galaxies · Physics 2024-06-05 S. Ranchod , S. A. Mao , R. Deane , S. S. Sridhar , A. Damas-Segovia , J. D. Livingston , Y. K. Ma

Standard analysis pipelines for measurements of Baryon Acoustic Oscillations (BAO) in galaxy surveys make use of a fiducial cosmological model to guide the data compression required to transform from observed redshifts and angles to the…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-25 Paul Carter , Florian Beutler , Will J. Percival , Joseph DeRose , Risa H. Wechsler , Cheng Zhao

Calibrating out per-antenna signal chain effects is an essential step in analyzing radio interferometric data. For drift-scanning arrays, robustly calibrating the data is especially challenging due to the lack of the ability to track a…

Instrumentation and Methods for Astrophysics · Physics 2026-02-09 Robert Pascua , Jonathan Sievers , Adrian Liu

We present new software to cross-match low-frequency radio catalogues: the Positional Update and Matching Algorithm (PUMA). PUMA combines a positional Bayesian probabilistic approach with spectral matching criteria, allowing for confusing…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 J. L. B. Line , R. L. Webster , B. Pindor , D. A. Mitchell , C. M. Trott

Observation of the redshifted 21-cm signal from Cosmic Dawn and Epoch of Reionization is a challenging endeavor in observational cosmology. Presence of orders of magnitude brighter astrophysical foregrounds and various instrumental…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-03 Aishrila Mazumder , Abhirup Datta , Arnab Chakraborty , Suman Majumdar

We present a study on the inference of cosmological and astrophysical parameters using stacked galaxy cluster profiles. Utilizing the CAMELS-zoomGZ simulations, we explore how various cluster properties--such as X-ray surface brightness,…

This paper focuses on assessing the limitations in the direction-finding process of radio sources with directional antennas in an urbanized environment, demonstrating how signal source antenna parameters, such as beamwidth and maximum…

Information Theory · Computer Science 2025-03-25 Cezary Ziolkowski , Jan M. Kelner

Mega-constellations in Low Earth Orbit have the potential to revolutionise worldwide internet access. The concomitant potential of these mega-constellations to impact space sustainability, however, has prompted concern from space actors as…

Systems and Control · Electrical Eng. & Systems 2022-07-12 Calum Spring-Turner , Raj Thilak Rajan

Spatial data display correlation between observations collected at neighboring locations. Generally, machine and deep learning methods either do not account for this correlation or do so indirectly through correlated features and thereby…

Methodology · Statistics 2024-10-08 Matthew J. Heaton , Andrew Millane , Jake S. Rhodes

Forthcoming radio surveys will include full polarisation information, which can be potentially useful for weak lensing observations. We propose a new method to measure the (integrated) gravitational field between a source and the observer,…

Astrophysics of Galaxies · Physics 2021-12-08 Jérémie Francfort , Giulia Cusin , Ruth Durrer

In the rest of this volume Lahav and Fisher have presented the method of Spherical Harmonic Analysis (SHA) and its use in estimating cosmologically interesting parameters. Here I demonstrate the use of SHA in cross-correlating galazy…

Astrophysics · Physics 2007-05-23 Caleb. A. Scharf

Galaxy morphology is one of the most fundamental ways to describe galaxy properties, but the morphology we observe may be affected by wavelength and spatial resolution, which may introduce systematic bias when comparing galaxies at…

Astrophysics of Galaxies · Physics 2023-07-27 Yao Yao , Jie Song , Xu Kong , Guanwen Fang , Hong-Xin Zhang , Xinkai Chen

Calibration is a key step in the signal processing pipeline of any radio astronomical instrument. The required sky, ionospheric and instrumental models for this step can suffer from various kinds of incompleteness. In this paper we analyze…

Instrumentation and Methods for Astrophysics · Physics 2019-02-08 A. Mouri Sardarabadi , L. V. E. Koopmans

Inflationary models predict a definite, model independent, angular dependence for the three-point correlation function of $\Delta T/T$ at large angles (greater than $\sim 1^\circ$) which we calculate. The overall amplitude is model…

Astrophysics · Physics 2009-10-22 Toby Falk , Raghavan Rangarajan , Mark Srednicki

The space astrometry mission GAIA will construct a dense optical QSO-based celestial reference frame. For consistency between the optical and radio positions, it will be important to align the GAIA frame and the International Celestial…

Astrophysics · Physics 2008-12-18 G. Bourda , P. Charlot , R. Porcas , S. Garrington
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