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Optical positions from the SuperCOSMOS Sky Survey have been compared in detail with accurate radio positions that define the second realisation of the International Celestial Reference Frame (ICRF2). The comparison was limited to the IIIaJ…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Adam Schaefer , Richard Hunstead , Helen Johnston

The limiting magnitude is a key issue for optical interferometry. Pairwise fringe trackers based on the integrated optics concepts used for example in GRAVITY seem limited to about K=10.5 with the 8m Unit Telescopes of the VLTI, and there…

The study of quantum reference frames (QRFs) is motivated by the idea of taking into account the quantum properties of the reference frames used, explicitly or implicitly, in our description of physical systems. Like classical reference…

Principal component analysis (PCA) frequently suffers from the disturbance of outliers and thus a spectrum of robust extensions and variations of PCA have been developed. However, existing extensions of PCA treat all samples equally even…

Machine Learning · Computer Science 2021-03-23 Rui Zhang , Hongyuan Zhang , Xuelong Li

Faraday complexity describes whether a spectropolarimetric observation has simple or complex magnetic structure. Quickly determining the Faraday complexity of a spectropolarimetric observation is important for processing large, polarised…

Instrumentation and Methods for Astrophysics · Physics 2021-07-01 M. J. Alger , J. D. Livingston , N. M. McClure-Griffiths , J. L. Nabaglo , O. I. Wong , C. S. Ong

We investigate the distribution and properties of Faraday rotating and synchrotron emitting regions in the Galactic ISM in the direction of the Galactic anti-centre. We apply Faraday tomography to a radio polarization dataset that we…

Astrophysics · Physics 2015-05-13 D. H. F. M. Schnitzeler , P. Katgert , A. G. de Bruyn

Principal component analysis (PCA) is traditionally implemented through a covariance or kernel matrix, leading-eigenvector extraction, and hard rank-$k$ projection. These steps can be computationally costly in high-dimensional and…

Quantum Physics · Physics 2026-05-28 Yewei Yuan , Michele Minervini , Mark M. Wilde , Nana Liu

Cosmological correlators encode invaluable information about the wavefunction of the primordial universe. In this letter we present a duality between correlators and wavefunction coefficients that is valid to all orders in the loop…

High Energy Physics - Theory · Physics 2025-01-07 David Stefanyszyn , Xi Tong , Yuhang Zhu

Direct imaging of exoplanets requires very high contrast levels, which are obtained using coronagraphs. But residual quasi-static aberrations create speckles in the focal plane downstream of the coronagraph which mask the planet. This…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 J. Mazoyer , P. Baudoz , R. Galicher , M. Mas , G. Rousset

During the last years, much attention has been paid to the astrometric implications of the galactic aberration in proper motions (GA). This effect causes systematic errors in astrometric measurements at a microarcsecond level. Some authors…

Instrumentation and Methods for Astrophysics · Physics 2015-02-03 Zinovy Malkin

We explore the use of principal component analysis (PCA) to characterize high-fidelity simulations and interferometric observations of the millimeter emission that originates near the horizons of accreting black holes. We show…

Instrumentation and Methods for Astrophysics · Physics 2018-09-05 Lia Medeiros , Tod R. Lauer , Dimitrios Psaltis , Feryal Özel

We present a new method of DEEM, the direct energy encircling method, for characterising the performance of fibres in most astronomical spectroscopic applications. It's a versatile platform to measure focal ratio degradation (FRD),…

Instrumentation and Methods for Astrophysics · Physics 2019-12-25 Yunxiang Yan , Qi Yan , Gang Wang , Weimin Sun , A-Li Luo , Zhenyu Ma , Qiong Zhang , Jian Li , Shuqing Wang

The International VLBI Service for Geodesy & Astrometry (IVS) regularly provides high-quality data to produce Earth Orientation Parameters (EOP), and for the maintenance and realization of the International Terrestrial and Celestial…

Model-independent analysis (MIA) methods are generally useful for analysing complex systems in which relationships between the observables are non-trivial and noise is present. Principle Component Analysis (PCA) is one of MIA methods…

Accelerator Physics · Physics 2015-06-17 Y. I. Kim , S. T. Boogert , Y. Honda , A. Lyapin , H. Park , N. Terunuma , T. Tauchi , J. Urakawa

Head-related transfer function (HRTF) plays an important role in the construction of 3D auditory display. This paper presents an individual HRTF modeling method using deep neural networks based on spatial principal component analysis. The…

Audio and Speech Processing · Electrical Eng. & Systems 2020-02-07 Mengfan Zhang , Zhongshu Ge , Tiejun Liu , Xihong Wu , Tianshu Qu

The accuracy of astrometric observations conducted via a space-borne optical interferometer orbiting the Earth is expected to approach a few microarcseconds. Data processing of such extremely high-precision measurements requires access to a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Sergei M. Kopeikin , N. V. Shuygina , M. V. Vasilyev , E. I. Yagudina , L. I. Yagudin

Geometric optics approximation is sufficient to describe the effects in the near-Earth environment. In this framework Faraday rotation is purely a reference frame (gauge) effect. However, it cannot be simply dismissed. Establishing local…

General Relativity and Quantum Cosmology · Physics 2023-01-27 Pravin Kumar Dahal , Daniel R. Terno

Diffraction tomography aims to recover an object's scattering potential from measured wave fields. In the classical setting, the object is illuminated by plane waves from many directions, and the Fourier diffraction theorem provides a…

Numerical Analysis · Mathematics 2026-03-11 Peter Elbau , Noemi Naujoks

We present an algorithm using Principal Component Analysis (PCA) to subtract galaxies from imaging data, and also two algorithms to find strong, galaxy-scale gravitational lenses in the resulting residual image. The combined method is…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 R. Joseph , F. Courbin , R. B. Metcalf , C. Giocoli , P. Hartley , N. Jackson , F. Bellagamba , J. -P. Kneib , L. Koopmans , G. Lemson , M. Meneghetti , G. Meylan , M. Petkova , S. Pires

Two reference systems (RS) are defined and used as the basis for investigating thermal effects of rotation through both random classical zero point radiation and quantum vacuum. Both RSs consist of an infinite number of instantaneous global…

Mathematical Physics · Physics 2007-05-23 Yefim S. Levin
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