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One of the challenges in spaceborne synthetic aperture radar (SAR) is modeling and mitigating radio frequency interference (RFI) artifacts in SAR imagery. Linear frequency modulated (LFM) signals have been commonly used for characterizing…

Image and Video Processing · Electrical Eng. & Systems 2025-09-24 Dehui Yang , Feng Xi , Qihao Cao , Huizhang Yang

It was decided in May 2012 that the Square Kilometre Array (SKA) will be built in Africa and Australia, two Southern Hemisphere continents. Here we discuss the plan for SKA design and construction, and how New Zealand radio astronomers can…

Instrumentation and Methods for Astrophysics · Physics 2012-12-27 Sergei Gulyaev , Paul Banks

Radio-astronomical observations are increasingly corrupted by RF interference, and online detection and filtering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the…

Astrophysics · Physics 2009-10-31 Amir Leshem , Alle-Jan van der Veen , Albert-Jan Boonstra

Signal artefacts due to Radio Frequency Interference (RFI) are a common nuisance in radio astronomy. Conventionally, the RFI-affected data are tagged by an expert data analyst in order to warrant data quality. In view of the increasing data…

Instrumentation and Methods for Astrophysics · Physics 2018-08-30 Paul Ray Burd , Karl Mannheim , Tobias März , Jonas Ringholz , Alexander Kappes , Matthias Kadler

Impulsive radio bursts that are detectable across cosmological distances constitute extremely powerful probes of the ionized Inter-Galactic Medium (IGM), intergalactic magnetic fields, and the properties of space-time itself. Their…

The radio spectrum is a finite and increasingly precious resource for astronomical research, as well as for other spectrum users. Keeping the frequency bands used for radio astronomy as free as possible of unwanted Radio Frequency…

Instrumentation and Methods for Astrophysics · Physics 2009-06-15 W. van Driel

Context. Apertif is a multi-beam receiver system for the Westerbork Synthesis Radio Telescope that operates at 1.1-1.5 GHz, which overlaps with various radio services, resulting in contamination of astronomical signals with radio-frequency…

Detection of the redshifted 21-cm signal of neutral hydrogen from the Cosmic Dawn and the Epoch of Reionization is one of the final frontiers of modern observational cosmology. The inherently faint signal makes it susceptible to…

Instrumentation and Methods for Astrophysics · Physics 2023-03-29 Aishrila Mazumder , Abhirup Datta , Mayuri Sathyanarayana Rao , Arnab Chakraborty , Saurabh Singh , Anshuman Tripathi , Madhurima Choudhury

We introduce a new Bayesian HI spectral line fitting technique capable of obtaining spectroscopic redshifts for millions of galaxies in radio surveys with the Square Kilometere Array (SKA). This technique is especially well-suited to the…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-28 Ian Harrison , Michelle Lochner , Michael L. Brown

In this third paper of a series on radio weak lensing for cosmology with the Square Kilometre Array, we scrutinise synergies between cosmic shear measurements in the radio and optical/near-IR bands for mitigating systematic effects. We…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Stefano Camera , Ian Harrison , Anna Bonaldi , Michael L. Brown

In this paper we use radiative transfer + N-body simulations to explore the feasibility of measurements of cross-correlations between the 21cm field observed by the Square Kilometer Array (SKA) and high-z Lyman Alpha Emitters (LAEs)…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-05 Dijana Vrbanec , Benedetta Ciardi , Vibor Jelic , Hannes Jensen , Ilian T. Iliev , Garrelt Mellema , Saleem Zaroubi

The Square Kilometre Array (SKA) is a planned radio interferometer of unprecedented scale that will revolutionize low-frequency radio astronomy when completed. In particular, one of its core science drivers is the systematic mapping of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-11 Nichole Barry , Gianni Bernardi , Bradley Greig , Nicholas Kern , Florent Mertens

We use two independent methods to forecast the dark energy measurements achievable by combining future galaxy redshift surveys based on the radio HI emission line with Cosmic Microwave Background (CMB) data from the {\sl Planck} satellite.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Filipe B. Abdalla , Chris Blake , Steve Rawlings

We introduce SigNova, a new semi-supervised framework for detecting anomalies in streamed data. While our initial examples focus on detecting radio-frequency interference (RFI) in digitized signals within the field of radio astronomy, it is…

Instrumentation and Methods for Astrophysics · Physics 2024-03-13 Paola Arrubarrena , Maud Lemercier , Bojan Nikolic , Terry Lyons , Thomas Cass

Strong evidence has recently emerged for a variation in the fine structure constant, $\alpha\equiv e^2/\hbar c$, over the history of the Universe. This was concluded from a detailed study of the relative positions of redshifted optical…

Astrophysics · Physics 2009-11-10 S. J. Curran , N. Kanekar , J. K. Darling

As radio telescopes become more sensitive, the damaging effects of radio frequency interference (RFI) become more apparent. Near radio telescope arrays, RFI sources are often easily removed or replaced; the challenge lies in identifying…

Instrumentation and Methods for Astrophysics · Physics 2018-08-01 Daniel Czech , Amit Mishra , Michael Inggs

The discovery and study of pulsars and Fast Radio Bursts (FRBs) in time-domain radio data is often hampered by radio frequency interference (RFI). Some of this terrestrial RFI is impulsive and bright, and relatively easy to identify and…

High Energy Astrophysical Phenomena · Physics 2021-06-09 Yogesh Maan , Joeri van Leeuwen , Dany Vohl

Long baseline radio interferometers can provide some interesting opportunities for future SETI searches. Known advantages (compared to single dishes or beam-formed arrays), include the large reduction in false-positives due to the…

Instrumentation and Methods for Astrophysics · Physics 2018-10-18 M. A. Garrett

It has been proposed recently that the SKA1-MID could be used to conduct an HI intensity mapping survey that could rival upcoming Stage IV dark energy surveys. However, measuring the weak HI signal is expected to be very challenging due to…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-01 Stuart E. Harper , Clive Dickinson , Richard Battye , Lucas Olivari

If Fast Radio Bursts (FRBs) are truly at astronomical, in particular cosmological, distances, they represent one of the most exciting discoveries in astrophysics of the past decade. However, the distance to FRBs has, to date, been estimated…

High Energy Astrophysical Phenomena · Physics 2015-05-06 Rob Fender , Tom Oosterloo