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Up to now, the completion of an ALMA interferometric observation is determined based on the achievement of a given shape and size of the synthesized beam and the noise RMS in the representative spectral range. This approach with respect to…

Instrumentation and Methods for Astrophysics · Physics 2020-12-17 Dirk Petry , María Díaz Trigo , Rüdiger Kneissl , Ignacio Toledo , Stefano Facchini

The detection of astrophysical Gamma-Ray Bursts (GRBs) has always been intertwined with the challenge of identifying the direction of the source. Accurate angular localization of better than a degree has been achieved to date only with…

Instrumentation and Methods for Astrophysics · Physics 2021-02-25 Roi Rahin , Luca Moleri , Alex Vdovin , Amir Feigenboim , Solomon Margolin , Shlomit Tarem , Ehud Behar , Max Ghelman , Alon Osovizky

We describe an "active" antenna system for HF/VHF (long wavelength) radio astronomy that has been successfully deployed 256-fold as the first station (LWA1) of the planned Long Wavelength Array. The antenna system, consisting of crossed…

This document presents a novel method for the intra-field calibration and imaging of the radio source SgrA*, observed with the Atacama Large Millimeter/submillimeter Array (ALMA). SgrA* is a complex source comprising two components: the…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Ezequiel Albentosa-Ruiz , Iván Martí-Vidal , Ciriaco Goddi , Alejandro Mus

Interferometers require accurate determination of the array configuration in order to produce reliable observations. A method is presented for finding the maximum-likelihood estimate of the telescope geometry, and of other instrumental…

Astrophysics · Physics 2009-11-07 Klaus Maisinger , M. P. Hobson , Richard D. E. Saunders , Keith J. B. Grainge

The low-frequency sky below $\sim$15 MHz (20 m) is obscured by the Earth's ionosphere, the layer of charged particles above the neutral atmosphere. Single spacecraft have made measurements in this band, but cannot achieve high or even…

Instrumentation and Methods for Astrophysics · Physics 2024-04-15 Mary Knapp , Lenny Paritsky , Ekaterina Kononov , Melodie M. Kao

Despite an emerging interest in MIMO radar, the utilization of its complementary strengths in combination with optical depth sensors has so far been limited to far-field applications, due to the challenges that arise from mutual sensor…

High-resolution astronomical imaging at sub-GHz radio frequencies has been available for more than 15 years, with the VLA at 74 and 330 MHz, and the GMRT at 150, 240, 330 and 610 MHz. Recent developments include wide-bandwidth upgrades for…

Instrumentation and Methods for Astrophysics · Physics 2014-02-21 H. T. Intema

Producing ultra-deep high-angular-resolution images with current and next-generation radio interferometers introduces significant computational challenges. In particular, the imaging is so demanding that processing large datasets,…

Instrumentation and Methods for Astrophysics · Physics 2025-01-14 J. M. G. H. J. de Jong , R. J. van Weeren , T. J. Dijkema , J. B. R. Oonk , H. J. A. Röttgering , F. Sweijen

Radiation detectors deployed as part of a large urban network or for homeland security monitoring must maintain reliable energy calibration even when subjected to substantial variations in temperature and ambient background radiation.…

Instrumentation and Detectors · Physics 2026-04-23 Marco Salathe , Nicolas Abgrall , Mark S. Bandstra , Tenzing H. Y. Joshi , Brian J. Quiter , Reynold J. Cooper

We present a case for significantly enhancing the utility and efficiency of the ngEHT by incorporating an additional 86 GHz observing band. In contrast to 230 or 345 GHz, weather conditions at the ngEHT sites are reliably good enough for 86…

Because of atmospheric turbulence, obtaining high angular resolution images with a high dynamic range is difficult even in the near infrared domain of wavelengths. We propose a novel technique to overcome this issue. The fundamental idea is…

Astrophysics · Physics 2009-11-11 G. Perrin , S. Lacour , J. Woillez , E. Thiebaut

The Low Frequency Array (LOFAR) is an ideal instrument to conduct deep extragalactic surveys. It has a large field of view and is sensitive to large scale and compact emission. It is, however, very challenging to synthesize thermal noise…

Millimeter-wave (mmWave) radar systems with large array have pushed radar sensing into a new era, thanks to their high angular resolution. However, our long-term experiments indicate that array elements exhibit phase drift over time and…

Signal Processing · Electrical Eng. & Systems 2025-07-01 Ruixu Geng , Yadong Li , Dongheng Zhang , Pengcheng Huang , Binquan Wang , Binbin Zhang , Zhi Lu , Yang Hu , Yan Chen

LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. LOFAR allows detailed sensitive high-resolution studies of the low-frequency radio sky. At the same time LOFAR also provides excellent short…

While conventional imaging in VLBI provides information only about the relative position between different features of a given source, phase-referenced observations can provide precise positional information with respect to an external…

Astrophysics · Physics 2007-05-23 Eduardo Ros

The major cornerstone of future ground-based astronomy is imaging and spectroscopy at the diffraction limit using adaptive optics. To exploit the potential of current AO systems, we have begun a survey around bright stars to study…

Astrophysics · Physics 2007-05-23 R. I. Davies , M. Lehnert , A. J. Baker , S. Rabien

Integrating efficient connectivity, positioning and sensing functionalities into 5G New Radio (NR) and beyond mobile cellular systems is one timely research paradigm, especially at mm-wave and sub-THz bands. In this article, we address the…

The emergence of beyond-licensed spectrum sharing in FR1 (0.45-6 GHz) and FR2 (24 - 52 GHz) along with the multi-antenna narrow-beam based directional transmissions demand a wideband spectrum sensing in temporal as well as spatial domains.…

Signal Processing · Electrical Eng. & Systems 2020-08-17 Himani Joshi , Sumit J. Darak , Mohammad Alaee-Kerahroodi , Bhavani Shankar Mysore Rama Rao