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Radio astronomical observations have very poor signal to noise ratios, unlike in other disciplines. On the other hand, it is possible to observe the object of interest for long time intervals as well as using a wider bandwidth.…

Astrophysics · Physics 2008-09-02 Sarod Yatawatta

In the past two decades, a rebirth of interest in low-frequency radio astronomy for 21 cm tomography of the Epoch of Reionization, has given rise to a new class of radio interferometers with $N \gg 100$ antennas. The availability of…

Instrumentation and Methods for Astrophysics · Physics 2022-08-11 Deepthi Gorthi

Space interferometry is the inevitable endpoint of high angular resolution astrophysics, and a key technology that can be leveraged to analyse exoplanet formation and atmospheres with exceptional detail. However, the anticipated cost of…

Instrumentation and Methods for Astrophysics · Physics 2020-06-04 Jonah T. Hansen , Michael J. Ireland

We review metrics to assess the radio quietness of sites used for radio astronomy. Concise metrics are needed to compare candidate sites for new telescopes, to monitor the quality of existing sites, and to design telescopes to work well at…

Instrumentation and Methods for Astrophysics · Physics 2014-03-03 Aaron Chippendale , Kjetil Wormnes

We report on the detection of source noise in the time domain at 162MHz with the Murchison Widefield Array. During the observation the flux of our target source Virgo A (M87) contributes only $\sim$1\% to the total power detected by any…

Instrumentation and Methods for Astrophysics · Physics 2021-04-14 John Morgan , Ron Ekers

The Naval Research Laboratory and the National Radio Astronomy Observatory completed implementation of a low frequency capability on the VLA at 73.8 MHz in 1998. This frequency band offers unprecedented sensitivity (~25 mJy/beam) and…

LOFAR, the Low Frequency Array, is a large radio telescope consisting about 100 soccer field sized antenna stations spread over a region of 400 km in diameter. It will operate in the frequency range from ~10 to 240 MHz, with a resolution at…

Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analysed the radio-frequency interference (RFI) situation in two…

Low-frequency radio astronomy is limited by severe ionospheric distortions below 50 MHz and complete reflection of radio waves below 10-30 MHz. Shielding of man-made interference from long-range radio broadcasts, strong natural radio…

Cosmology and Nongalactic Astrophysics · Physics 2009-03-09 Sebastian Jester , Heino Falcke

The Atacama Millimeter/Submillimeter Array (ALMA) remains unparalleled in sensitivity at radio frequencies above 35 GHz. In this paper, we explore ALMA's potential for narrowband technosignature detection, considering factors such as the…

Instrumentation and Methods for Astrophysics · Physics 2024-12-02 Louisa A Mason , Michael A Garrett , Kelvin Wandia , Andrew P V Siemion

Interferometric measurements with arrays of radio antennas are a powerful and widely used technique in astronomy. Recently, this technique has been revisited for the reconstruction of extensive air showers [1]. This radio-interferometric…

Instrumentation and Methods for Astrophysics · Physics 2022-12-16 Felix Schlüter , Tim Huege

Digital radio arrays are widely used for the low-frequency radio astronomy as well as for detection of air-showers induced by high-energy cosmic rays and neutrinos. Since the radio emission from air-showers forms short broadband pulses with…

The indirect detection of cosmic rays via the radio signal of extensive air showers is gaining a lot of ground. Many new arrays of radio antennas are under construction or in the phase of development. Calibrating these arrays is important…

Instrumentation and Methods for Astrophysics · Physics 2023-01-30 Max Büsken , Tomáš Fodran , Tim Huege

A promising approach to detect high-energy tau neutrinos is through the measurement of impulsive radio emission from horizontal air showers initiated in the Earth's atmosphere. Observations at frequencies between 30 and 80 MHz seem…

Instrumentation and Methods for Astrophysics · Physics 2024-10-31 Tim Huege , Oliver Krömer

Astronomers usually need the highest angular resolution possible, but the blurring effect of diffraction imposes a fundamental limit on the image quality from any single telescope. Interferometry allows light collected at widely-separated…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 John D. Monnier , Ronald J. Allen

Fast radio bursts (FRBs) are extraordinary astrophysical phenomena characterized by short radio pulses that last only a few milliseconds, yet their power can surpass that of 500 million suns. To date, most detected FRBs originate from…

LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30-240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to…

At sufficiently low frequencies, no ground-based radio array will be able to produce high resolution images while looking through the ionosphere. A space-based array will be needed to explore the objects and processes which dominate the sky…

The dynamical evolution and radiative properties of luminous radio galaxies and quasars of the FRII type, are well understood. As a result, through the use of detailed modeling of the observed radio emission of such sources, one can…

Astrophysics of Galaxies · Physics 2021-12-08 Anna Wojtowicz , Lukasz Stawarz , Jerzy Machalski , Luisa Ostorero

We present a new approach to multi-frequency synthesis in radio astronomy. Using Bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. In principle, the bandwidth of a wide-band…

Instrumentation and Methods for Astrophysics · Physics 2015-09-16 H. Junklewitz , M. A. Bell , T. Enßlin