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Recent interferometers (e.g. ALMA and NOEMA) allow us to obtain the detailed brightness distribution of the astronomical sources in 3 dimension (R.A., Dec., frequency). However, the interpixel correlation of the noise due to the limited uv…

Instrumentation and Methods for Astrophysics · Physics 2022-07-27 Takafumi Tsukui , Satoru Iguchi , Ikki Mitsuhashi , Kenichi Tadaki

The measurement of shape parameters of sources in astronomical images is usually performed by assuming that the underlying noise is uncorrelated. Spatial noise correlation is however present in practice due to various observational effects…

Astrophysics · Physics 2007-05-23 A. Refregier , S. T. Brown

This manual is intended to help ALMA and other interferometer users improve images by recognising limitations and how to overcome them and deciding when and how to use self-calibration. The images provided by the ALMA Science Archive are…

Instrumentation and Methods for Astrophysics · Physics 2022-07-13 A. M. S. Richards , E. Moravec , S. Etoka , E. B. Fomalont , A. F. Pérez-Sánchez , M. C. Toribio , R. A. Laing

In the Monte Carlo (MC) method statistical noise is usually present. Statistical noise may become dominant in the calculation of a distribution, usually by iteration, but is less Important in calculating integrals. The subject of the…

Computational Physics · Physics 2013-11-08 Mihály Makai , Zoltán Szatmáry

Knowledge of the noise distribution in magnitude diffusion MRI images is the centerpiece to quantify uncertainties arising from the acquisition process. The use of parallel imaging methods, the number of receiver coils and imaging filters…

Computer Vision and Pattern Recognition · Computer Science 2018-10-03 Samuel St-Jean , Alberto De Luca , Max A. Viergever , Alexander Leemans

This paper investigates the possibility of improving radio interferometric images using an algorithm inspired by an optical method known as "lucky imaging", which would give more weight to the best-calibrated visibilities used to make a…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 Etienne Bonnassieux , Cyril Tasse , Oleg Smirnov , Philippe Zarka

I present in this paper a method to calibrate data obtained from optical and infrared interferometers. I show that correlated noises and errors need to be taken into account for a very good estimate of individual error bars but also when…

Astrophysics · Physics 2009-11-07 G. Perrin

Cosmological observables rely heavily on summary statistics such as two-point correlation functions. In many practical cases (e.g. the weak-lensing cosmic shear), those correlation functions are estimated from a finite, discrete sample of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-24 Pierre Fleury

Intensity interferometry is a well known method in astronomy. Recently, a related method called incoherent diffractive imaging (IDI) was proposed to apply intensity correlations of x-ray fluorescence radiation to determine the 3D…

Optics · Physics 2020-08-27 Fabian Trost , Kartik Ayyer , Henry Chapman

Periodograms are common tools used to search for periodic signals in unevenly spaced time series. The significance of periodogram peaks is often assessed using false alarm probability (FAP), which in most studies assumes uncorrelated noise…

Instrumentation and Methods for Astrophysics · Physics 2020-03-11 J. -B. Delisle , N. Hara , D. Ségransan

It is a well-established principle that cross-correlating seismic observations at different receiver locations can yield estimates of band-limited inter-receiver Green's functions. This principle, known as seismic interferometry, is a…

Geophysics · Physics 2021-08-11 Daniella Ayala-Garcia , Andrew Curtis , Michal Branicki

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…

Instrumentation and Methods for Astrophysics · Physics 2009-07-28 Bojan Nikolic

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…

Instrumentation and Methods for Astrophysics · Physics 2020-09-11 Adrian T. Sutinjo , Benjamin McKinley , Leonid Belostotski , Daniel C. X. Ung , Jishnu N. Thekkeppattu

Precise measurement of frequency sensitivity coefficients (FSCs) of some physical effects contributing to uncertainty is an important work in type-B uncertainty (u_B) evaluation of atomic frequency standards. We proposed a method based on…

Quantum Physics · Physics 2019-09-11 Qian Wang , Ning Zhang , Rong Wei , Yuzhu Wang

Accurately estimating the statistical properties of noise is important in data analysis for space-based gravitational wave detectors. Noise in different time-delay interferometry channels correlates with each other. Many studies often…

Instrumentation and Methods for Astrophysics · Physics 2025-06-18 Ya-Nan Li , Yi-Ming Hu , En-Kun Li

We quantify the impact of spatio-temporally correlated Gaussian quantum noise on frequency estimation by Ramsey interferometry. While correlations in a classical noise environment can be exploited to reduce uncertainty relative to the…

Quantum Physics · Physics 2018-08-31 Félix Beaudoin , Leigh M. Norris , Lorenza Viola

Even the most sensitive cosmic microwave background anisotropy experiments have signal to noise ratios <=5, so that an accurate determination of the properties of the cosmological signal requires a careful assessment of the experimental…

Astrophysics · Physics 2009-10-30 C. M. Gutierrez

I calculate the noise in the measured correlation functions and spectra of digitized, noiselike signals. In the spectral domain, the signals are drawn from a Gaussian distribution with variance that depends on frequency. Nearly all…

Astrophysics · Physics 2007-05-23 C. R. Gwinn

The present generation of weak lensing surveys will be superseded by surveys run from space with much better sky coverage and high level of signal to noise ratio, such as SNAP. However, removal of any systematics or noise will remain a…

Astrophysics · Physics 2009-11-10 Dipak Munshi , Patrick Valageas

The detection of anisotropies with respect to a given direction in a vector field is a common problem in astronomy. Several methods have been proposed that rely on the distribution of the acute angles between the data and a reference…

Instrumentation and Methods for Astrophysics · Physics 2022-03-01 F. Dávila-Kurbán , M. Lares , D. Garcia Lambas
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