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The cross-correlation function (CCF) is commonly employed in the study of AGN, where it is used to probe the structure of the broad line region by line reverberation, to study the continuum emission mechanism by correlating multi-waveband…

天体物理仪器与方法 · 物理学 2013-02-07 Tal Alexander

Accurate radial velocities ($v_{\rm rad}$) of Cepheids are mandatory within the context of distance measurements via the Baade-Wesselink technique. The most common $v_{\rm rad}$ derivation method consists in cross-correlating the observed…

This work reports the discovery of cycle-to-cycle modulated spectral line and atmospheric velocity gradient variability in long-period Cepheids based on 925 high-resolution optical spectra of $\ell$ Carinae (P $\sim$ 35.5 d) recorded during…

太阳与恒星天体物理 · 物理学 2016-08-19 Richard I. Anderson

We present a novel technique that uses the autocorrelation of the spectrum of a star to measure the line broadening caused by the modulus of its average surface magnetic field. The advantage of the autocorrelation comes from the fact that…

太阳与恒星天体物理 · 物理学 2015-10-21 Ermanno F. Borra , David Deschatelets

Flexible modelling of the autocovariance function (ACF) is central to time-series, spatial, and spatio-temporal analysis. Modern applications often demand flexibility beyond classical parametric models, motivating non-parametric…

统计方法学 · 统计学 2025-06-30 Lachlan Astfalck

The "spectral correlation function" analysis we introduce in this paper is a new tool for analyzing spectral-line data cubes. Our initial tests, carried out on a suite of observed and simulated data cubes, indicate that the spectral…

天体物理学 · 物理学 2009-10-31 Erik W. Rosolowsky , Alyssa A. Goodman , David J. Wilner , Jonathan P. Williams

We present a generalised estimator for the autocorrelation function, S-ACF, which is an extended version of the standard estimator of the autocorrelation function (ACF). S-ACF is a versatile definition that can robustly and efficiently…

天体物理仪器与方法 · 物理学 2023-05-16 Lars T. Kreutzer , Edward Gillen , Joshua T. Briegal , Didier Queloz

Parabolic mean curvature flow-driven active contour models (PMCF-ACMs) are widely used for image segmentation, yet they suffer severe degradation under high-intensity noise because gradient-descent evolutions exhibit the well-known zig-zag…

计算机视觉与模式识别 · 计算机科学 2025-11-17 Saiyu Hu , Chunlei He , Jianfeng Zhang , Dexing Kong , Shoujun Huang

Structure and dynamics at soft-matter interfaces play an important role in nature and technical applications. Optical single-molecule investigations are non-invasive and capable to reveal heterogeneities at the nanoscale. In this work we…

Rotational modulation of stellar light curves due to dark spots encloses information on spot properties and, thus, on magnetic activity. In particular, the decay of the autocorrelation function (ACF) of light curves is presumed to be linked…

太阳与恒星天体物理 · 物理学 2021-08-20 A. R. G. Santos , S. Mathur , R. A. García , M. S. Cunha , P. P. Avelino

This paper aims to develop the first method to reconstruct the shape of the RV curves of short-period fundamental-mode Cepheids, based exclusively on their pulsation period and the morphology of their $V$-band light curves (LCs). We…

A new method for measuring the shear induced by gravitational light deflection is proposed. It is based on analyzing the anisotropy induced in the auto-correlation function (ACF) of the extragalactic background light which is produced by…

天体物理学 · 物理学 2007-05-23 L. Van Waerbeke , Y. Mellier , P. Schneider , B. Fort , G. Mathez

We propose an anisotropic generalisation of the line correlation function (ALCF) to separate and quantify phase information in the large-scale structure of galaxies. The line correlation function probes the strictly non-linear regime of…

宇宙学与河外天体物理 · 物理学 2015-10-22 Alexander Eggemeier , Thorsten Battefeld , Robert E. Smith , Jens Niemeyer

The random motion of molecules in living cells has consistently been reported to deviate from standard Brownian motion, a behavior coined as ``anomalous diffusion''. Fluorescence Correlation Spectroscopy (FCS) is a powerful method to…

The cross correlation method (hereafter CC) is widely used to derive the radial velocity curve of Cepheids when the signal to noise of the spectra is low. However, if it is used with the wrong projection factor, it might introduce some…

太阳与恒星天体物理 · 物理学 2015-05-13 N. Nardetto , W. Gieren , P. Kervella , P. Fouque , J. Storm , G. Pietrzynski , D. Mourard , D. Queloz

Autocorrelation measurement is theoretically demonstrated to characterize attosecond pulses by studying the two-photon double ionization (TPDI) process. An interferometric autocorrelation curve is presented in the change of TPDI probability…

原子物理 · 物理学 2024-09-25 Fei Li , Kun Zhao , Bing-Bing Wang , Xin-Kui He , Zhi-Yi Wei

Recent simulations find that hot gas accretion onto compact accretors are often highly turbulent and diskless, and show power-law density profiles with slope $\alpha_\rho\approx-1$. These results are consistent with observational…

高能天体物理现象 · 物理学 2023-07-19 Wenrui Xu

Fluorescence Correlation Spectroscopy (FCS) is a powerful single-molecule technique which allows for measuring motion (diffusion, flow), concentration, and molecular interaction kinetics of fluorescent molecules from picomolar to micromolar…

We study correlations of hydrodynamic fluctuations in shear flow analytically and also by dissipative particle dynamics~(DPD) simulations. The hydrodynamic equations are linearized around the macroscopic velocity field and then solved by a…

流体动力学 · 物理学 2019-05-02 Xin Bian , Mingge Deng , George Em Karniadakis

Dual-tip phase-detection probes can be used to measure flow properties in gas-liquid flows. Traditionally, time-averaged interfacial velocities have been obtained through cross-correlation analysis of long time-series of phase fraction…

流体动力学 · 物理学 2020-01-14 Matthias Kramer , Benjamin Hohermuth , Daniel Valero , Stefan Felder
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