Related papers: Fourier-Correlation Imaging
Results from a survey of the parsec scale Faraday rotation measure properties for 40 quasars, radio galaxies and BL Lac objects are presented. Core rotation measures for quasars vary from approximately 500 to several thousand radians per…
Some pulsating stars are good clocks. When they are found in binary stars, the frequencies of their luminosity variations are modulated by the Doppler effect caused by orbital motion. For each pulsation frequency this manifests itself as a…
We present design equations for a two-element closely-spaced interferometer for measuring the noise temperature of a uniform sky. Such an interferometer is useful for observing highly diffuse radio sources such as the Milky Way and…
The third-generation South Pole Telescope camera is designed to measure the cosmic microwave background across three frequency bands (95, 150 and 220 GHz) with ~16,000 transition-edge sensor (TES) bolometers. Each multichroic pixel on a…
The light from a source at a distance d will arrive at detectors separated by 100 AU at times that differ by as much as 120 (d/100 Mpc)^{-1} nanoseconds because of the curvature of the wavefront. At gigahertz frequencies, the arrival time…
A new generation of radio telescopes are currently being built with the goal of tracing the cosmic distribution of atomic hydrogen at redshifts 6-15 through its 21-cm line. The observations will probe the large-scale brightness fluctuations…
We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of Fast Fourier…
For a first characterization, we used the two KETEK-PM3325-WB SiPMs each equipped with a 3x3x5 mm${}^3$ LYSO scintillation crystal provided with the PETsys TOFPET2 ASIC Evaluation Kit. We changed the lower of two discriminator thresholds…
Measuring thermodynamic quantities can be easy or not, depending on the system that is being studied. For a macroscopic object, measuring temperatures can be as simple as measuring how much a column of mercury rises when in contact with the…
By observing bright and compact astronomical sources while also taking data with the 183 GHz Water Vapour Radiometers, ALMA will be able to measure the `empirical' relationship between fluctuations in the phase of the astronomical signal…
Scattering from objects near an antenna produce correlated signals from strong compact radio sources in a manner similar to those used by the Sea Interferometer to measure the radio source positions using the fine frequency structure in the…
In this paper, we describe the principle of a multi-aperture interferometer that uses a phase-shifting technique and is suitable for quick, snapshot imaging of astrophysical objects at extreme angular resolution through Fourier inversion. A…
An approach is demonstrated for comparing the temperature of the upper atmosphere obtained by ground-based and satellite methods. A method for calibrating ground-based instruments (Fabry-Perot interferometer) based on the data obtained and…
Super-resolution imaging based on single molecule localization allows accessing nanometric-scale information in biological samples with high precision. However, complete measurements including molecule orientation are still challenging.…
Coherence refers to correlations between field vibrations at two separate points in degrees of freedom such as space, time, and polarisation. In the context of space, coherence theory has been formulated between two transverse positions…
Satellite quantum communications have rapidly evolved in the past few years, culminating in the proposal, development, and deployment of satellite missions dedicated to quantum key distribution and the realization of fundamental tests of…
This article begins with the discussions on the formation of speckles in the case of non-coherent quasi monochromatic source and of ways to detect them. Prior to this, a brief introduction on the behavior of the atmosphere and its effect on…
Nowadays, tens of satellites carry hyperspectral spectrometers. Such instruments allow decomposing the light that exits the atmosphere from its top into hundreds to thousands of contiguous spectral channels. By analysis of the light…
Using a combination of theory and computer simulations, we study the translocation of an RNA molecule, pulled through a solid-state nanopore by an optical tweezer, as a method to determine its secondary structure. The resolution with which…
The comparison of optical reference frequency signals over free-space optical links is limited by the relative motion between local and remote sites. For ground to low earth orbit comparison, the expected Doppler shift and Doppler rate…