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The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA…

A Radio interferometer comprises several antennas, spared over a large area. Say ALMA(Atacama Large Millimeter/submillimeter Array), VLA(very large array), VLBA(Very Long Baseline Array), GMRT(Giant Metrewave Radio Telescope), MWA(…

Instrumentation and Methods for Astrophysics · Physics 2023-10-09 Akash Kulkarni

Weak gravitational lensing observations probe the spectrum and evolution of density fluctuations and the cosmological parameters which govern them but are currently limited to small fields and subject to selection biases. We show how the…

Astrophysics · Physics 2009-10-31 Asantha Cooray , Wayne Hu , Jordi Miralda-Escude

The analysis of optical spectra - emission or absorption -- has been arguably the most powerful approach for discovering and understanding matters. The invention and development of many kinds of spectrometers have equipped us with versatile…

The Large Array Survey Telescope (LAST) is designed to survey the variable and transient sky at high temporal cadence. The array is comprised of 48 F/2.2 telescopes of 27.9cm aperture, coupled to full-frame backside-illuminated cooled CMOS…

In the near future, the Expanded Very Large Array (EVLA) will allow surveys for maser sources with unprecedented sensitivity, spectral coverage and spectroscopic capabilities. In particular, comprehensive surveys for many maser species with…

Astrophysics · Physics 2009-11-13 Karl M. Menten

The VLT Survey Telescope Survey of Mass Assembly and Structural Hierarchy (VST-SMASH) aims to detect tidal features and remnants around very nearby galaxies, a unique and essential diagnostic of the hierarchical nature of galaxy formation.…

We report a detection of the coherent distortion of faint galaxies arising from gravitational lensing by foreground structures. This ``cosmic shear'' is potentially the most direct measure of the mass power spectrum, as it is unaffected by…

Astrophysics · Physics 2011-05-05 David Bacon , Alexandre Refregier , Richard Ellis

The next-generation Very Large Array (ngVLA) is an astronomical observatory planned to operate at centimeter wavelengths (25 to 0.26 centimeters, corresponding to a frequency range extending from 1.2 to 116 GHz). The observatory will be a…

Low-noise phased arrays are essential for the next generation of microwave and submillimetre wave astronomy. We analyze their behaviour from a functional perspective, and show that their operation is intimately related to the mathematical…

Astrophysics · Physics 2007-07-12 S. Withington , G. Saklatvala , M. P. Hobson

The high sensitivity of the new generation of radio telescopes such as the Square Kilometre Array (SKA) will allow cosmological weak lensing measurements at radio wavelengths that are competitive with optical surveys. We present an…

Instrumentation and Methods for Astrophysics · Physics 2016-09-23 Marzia Rivi , Lance Miller , Sphesihle Makhathini , Filipe Batoni Abdalla

The coherent image distortions induced by weak gravitational lensing can be used to measure the power spectrum of density inhomogeneities in the universe. We present our on-going effort to detect this effect with the FIRST radio survey,…

We discuss the unique opportunities for maser astrometry with the inclusion of the Square Kilometre Array (SKA) in Very Long Baseline Interferometry (VLBI) networks. The first phase of the SKA will enable observations of hydroxyl and…

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

Contemporary cosmic microwave background (CMB) experiments typically have observing bands covering the range 20 - 800 GHz. Certain science goals, including the detection of $\mu$-type distortions to the CMB spectrum and the characterization…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-07 David Zegeye , Thomas Crawford , Jens Chluba , Mathieu Remazeilles , Keith Grainge

The Large Array Survey Telescope (LAST) is a wide-field visible-light telescope array designed to explore the variable and transient sky with a high cadence. LAST will be composed of 48, 28-cm f/2.2 telescopes (32 already installed)…

We report the use of the Australia Telescope Compact Array (ATCA) to conduct polarimetric observations of the sky at 5 GHz. The ATCA is normally operated as an interferometer array, but these observations were conducted in a split array…

Astrophysics · Physics 2010-11-11 D. McConnell , E. Carretti , R. Subrahmanyan

This paper proposes a new sparse array geometry for 2-D (azimuth and elevation) DOA (direction-of-arrival) estimation. The proposed array geometry is V-shaped sparse array and it is composed of two linear portions which are crossing each…

Signal Processing · Electrical Eng. & Systems 2020-04-28 Ahmet M. Elbir

In this proceeding, we summarize the key science goals and reference design for a next-generation Very Large Array (ngVLA) that is envisaged to operate in the 2030s. The ngVLA is an interferometric array with more than 10 times the…

Instrumentation and Methods for Astrophysics · Physics 2018-08-22 Eric J. Murphy

This paper describes a programme to map large-scale cosmic structures on the largest possible scales by using the Five hundred metre Aperture Spherical Telescope (FAST) to make a 21 cm (red-shifted) intensity map of the sky for the range…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 George F. Smoot , Ivan Debono