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In radio astronomy, accurate calibration is of crucial importance for the new generation of radio interferometers. More specifically, because of the potential presence of outliers which affect the measured data, robustness needs to be…

Instrumentation and Methods for Astrophysics · Physics 2018-08-01 Virginie Ollier , Mohammed Nabil El Korso , André Ferrari , Rémy Boyer , Pascal Larzabal

We compare performances of ground-based single-mode and multimode (speckle) interferometers in the presence of partial Adaptive Optics correction of atmospheric turbulence. It is first shown that for compact sources (i.e. sources smaller…

Astrophysics · Physics 2009-11-10 E. Tatulli , P. Mege , A. Chelli

Interstellar scattering is known to broaden distant objects spatially and temporally. The latter aspect is difficult to analyse, unless the signals carry their own time stamps. Pulsars are so kind to do us this favour. Typically the…

Astrophysics of Galaxies · Physics 2019-04-26 Olaf Wucknitz

We study the weak-value amplification (WVA) in a phase measurement with an optical interferometer in which shot noise limits the sensitivity. We compute the signal and the shot noise including the full-order interaction terms of the WVA,…

Quantum Physics · Physics 2012-06-26 Atsushi Nishizawa , Kouji Nakamura , Masa-Katsu Fujimoto

We analyze the creation of spin squeezed atomic ensembles by simultaneous dispersive interactions with several optical frequencies. A judicious choice of optical parameters enables optimization of an interferometric detection scheme that…

Quantum Physics · Physics 2009-05-14 M. Saffman , D. Oblak , J. Appel , E. S. Polzik

Two-stage least squares (TSLS) estimators and variants thereof are widely used to infer the effect of an exposure on an outcome using instrumental variables (IVs). They belong to a wider class of two-stage IV estimators, which are based on…

Methodology · Statistics 2015-10-08 Stijn Vansteelandt , Vanessa Didelez

We present a $Z_1^2$-based framework for estimating the spin frequency and frequency derivative of high-energy pulsars from Poisson-limited photon event lists. The key point is that the width of a coherent detection peak is not, by itself,…

Instrumentation and Methods for Astrophysics · Physics 2026-05-15 Akshat Singhal , Rohit Nair , Devendra Sahu , Gayathri Raman , Suman Bala

Interferometric observations with three telescopes or more provide two observables: closure phase information together with visibilities measurements. When using single-mode interferometers, both observables have to be redefined in the…

Astrophysics · Physics 2009-11-11 E. Tatulli , A. Chelli

Nonlinear combinations of direct observables are often used to estimate quantities of theoretical interest. Without sufficient caution, this could lead to biased estimations. An example of great interest is the skewness $S_3$ of the galaxy…

Astrophysics · Physics 2009-10-31 Lam Hui , Enrique Gaztanaga

We compare signal and noise for observations of the scintillating pulsar B0834+06, using very-long baseline interferometry and a single-dish spectrometer. Comparisons between instruments and with models suggest that amplitude variations of…

Astrophysics of Galaxies · Physics 2015-05-27 C. R. Gwinn , M. D. Johnson , T. V. Smirnova , D. R. Stinebring

The sensitivity achievable by a pair of VIRGO detectors to stochastic and isotropic gravitational wave backgrounds of cosmological origin is discussed in view of the development of a second VIRGO interferometer. We describe a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 D. Babusci , M. Giovannini

The propagation of errors through the uniform disk visibility function is examined. Implications of those errors upon measures of absolute visibility through optical and near-infrared interferometers are considered within the context of…

Astrophysics · Physics 2009-11-11 Gerard T. van Belle , Gerald van Belle

Modern radio interferometers sensitive to low frequencies will make use of wide-band detectors. For such wide bandwidths, dispersive atmospheric effects introduce variations in the fringe delay which change through the band of the…

Instrumentation and Methods for Astrophysics · Physics 2011-01-25 I. Marti-Vidal

Position and frequency switching techniques used for the removal of the bandpass dependence of radio astronomical spectra are presented and discussed in detail. Both methods are widely used, although the frequency dependence of the system…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 B. Winkel , A. Kraus , U. Bach

The amplification obtained using weak values is quantified through a detailed investigation of the signal to noise ratio for an optical beam deflection measurement. We show that for a given deflection, input power and beam radius, the use…

Quantum Physics · Physics 2009-10-14 David J. Starling , P. Ben Dixon , Andrew N. Jordan , John C. Howell

Most optical and IR spectra are now acquired using detectors with finite-width pixels in a square array. This paper examines the effects of such pixellation, using computed simulations to illustrate the effects which most concern the…

Instrumentation and Methods for Astrophysics · Physics 2017-09-05 J. Gordon Robertson

The Laser Interferometer Space Antenna (LISA) mission aims to detect gravitational waves by interferometrically measuring the change of separation between free-falling test masses (TMs). LISA's interferometers must deliver pm/rtHz…

Efficient estimators of Fourier-space statistics for large number of objects rely on Fast Fourier Transforms (FFTs), which are affected by aliasing from unresolved small scale modes due to the finite FFT grid. Aliasing takes the form of a…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-09 Emiliano Sefusatti , Martin Crocce , Roman Scoccimarro , Hugh Couchman

Long duration noisy-looking waveforms such as those obtained in randomly multiply scattering and reverberant media are complex; they resist direct interpretation. Nevertheless, such waveforms are sensitive to small changes in the source of…

Geophysics · Physics 2015-05-27 Richard L Weaver , Céline Hadziioannou , Eric Larose , Michel Campillo

We characterize the performance of the widely-used least-squares estimator in astrometry in terms of a comparison with the Cramer-Rao lower variance bound. In this inference context the performance of the least-squares estimator does not…

Instrumentation and Methods for Astrophysics · Physics 2015-11-18 Rodrigo A. Lobos , Jorge F. Silva , Rene A. Mendez , Marcos Orchard