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Related papers: Inferring solar differential rotation through norm…

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We present an adaptation of the rotation-corrected, m-averaged spectrum technique designed to observe low signal-to-noise-ratio, low-frequency solar p modes. The frequency shift of each of the 2l+1 m spectra of a given (n,l) multiplet is…

Solar and Stellar Astrophysics · Physics 2011-02-11 D. Salabert , J. Leibacher , T. Appourchaux , F. Hill

We present the identification of very low frequency g modes in the asymptotic regime and two important parameters that have long been waited for: the core rotation rate, and the asymptotic equidistant period spacing of these g modes. The…

Measurement of the differential rotation of the Sun's interior is one of the great achievements of helioseismology, providing important constraints for stellar physics. The technique relies on observing and analyzing rotationally-induced…

Time-distance helioseismology is a set of powerful tools to study features below the Sun's surface. Inverse methods are needed to interpret time-distance measurements, with many examples in the literature. However, techniques that utilize a…

Solar and Stellar Astrophysics · Physics 2020-10-14 Jason Jackiewicz

Global hydrodynamic simulations of internal solar dynamics have focused on replicating the conditions for solar-like differential rotation and meridional circulation using the results of helioseismic inversions as a constraint. Inferences…

Bayesian methods are becoming more widely used in asteroseismic analysis. In particular, they are being used to determine oscillation frequencies, which are also commonly found by Fourier analysis. It is important to establish whether the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Timothy R. White , Brendon J. Brewer , Timothy R. Bedding , Dennis Stello , Hans Kjeldsen

Context. Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles. Aims. We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes. Methods. A first-order…

Solar and Stellar Astrophysics · Physics 2020-08-05 C. R. Goddard , A. C. Birch , D. Fournier , L. Gizon

Solar internal rotation at high latitudes is poorly constrained by acoustic-mode helioseismology. Global inertial modes observed on the Sun are highly sensitive to solar differential rotation and may provide new diagnostics of rotation in…

Solar and Stellar Astrophysics · Physics 2026-05-20 Prithwitosh Dey , Laurent Gizon , Yuto Bekki

Normal-mode oscillation frequencies computed from stellar models differ from those which would be measured from stars with identical interior structures, because of modelling errors in the near-surface layers. These frequency differences…

Solar and Stellar Astrophysics · Physics 2021-10-20 J. M. Joel Ong , Sarbani Basu , Ian W. Roxburgh

Mode fitting or "peak-bagging" is an important procedure in helioseismology allowing one to determine the various mode parameters of solar oscillations. Here we describe a way of reducing the systematic bias in the fits of certain mode…

Solar and Stellar Astrophysics · Physics 2011-02-11 S. T. Fletcher , W. J. Chaplin , Y. Elsworth , R. New

Recent developments in instrumentation (e.g., in particular the Kepler and CoRoT satellites) provide a new opportunity to improve the models of stellar pulsations. Surface layers, rotation, and magnetic fields imprint erratic frequency…

Solar and Stellar Astrophysics · Physics 2015-06-04 M. Gruberbauer , D. B. Guenther , T. Kallinger

I present a matched-wave asymptotic analysis of the driving of solar oscillations by a general localised source. The analysis provides a simple mathematical description of the asymmetric peaks in the power spectrum in terms of the relative…

Astrophysics · Physics 2009-10-30 Colin S. Rosenthal

Helioseismic techniques such as ring-diagram analysis have often been used to determine the subsurface structural differences between solar active and quiet regions. Results obtained by inverting the frequency differences between the…

Astrophysics · Physics 2009-11-13 Chia-Hsien Lin , Sarbani Basu , Linghuai Li

Despite the strong evidence that the peaks in the spectrum of solar oscillations are asymmetric, most determinations of mode frequencies have been based on fits of symmetric Lorentzian profiles to the Fourier or power spectra of oscillation…

Departures from standard spherically symmetric solar models, in the form of perturbations such as global and local-scale flows and structural asphericities, result in the splitting of eigenfrequencies in the observed spectrum of solar…

Solar and Stellar Astrophysics · Physics 2020-07-03 Srijan Bharati Das , Tuneer Chakraborty , Shravan M. Hanasoge , Jeroen Tromp

Recent studies have established that peaks in solar oscillation power spectra are not Lorentzian in shape, but have a distinct asymmetry. Fitting a symmetric Lorentzian profile to the peaks therefore produces a shift in frequency of the…

The advent of space-based photometry missions in the early 21st century enabled the application to asteroseismic data of advanced inference techniques until then restricted to the field of helioseismology. The high quality of the…

Solar and Stellar Astrophysics · Physics 2022-06-24 Gaël Buldgen , Jérôme Bétrisey , Ian W. Roxburgh , Sergei V. Vorontsov , Daniel R. Reese

We present a comprehensive study of one method for measuring various parameters of global modes of oscillation of the Sun. Using velocity data taken by the Michelson Doppler Imager (MDI), we analyze spherical harmonic degrees l <= 300. Both…

Solar and Stellar Astrophysics · Physics 2015-11-18 Tim Larson , Jesper Schou

Helioseismic observations have provided valuable datasets with which to pursue the detailed investigation of solar interior dynamics. Among various methods to analyse these data, normal-mode coupling has proven to be a powerful tool, used…

Solar and Stellar Astrophysics · Physics 2021-10-20 Prasad Mani , Shravan Hanasoge

We determine the frequencies of solar oscillations covering a wide range of degree (100< l <4000) and frequency (1.5 <\nu<10 mHz) using the ring diagram technique applied to power spectra obtained from MDI (Michelson Doppler Imager) data.…

Astrophysics · Physics 2009-10-31 H. M. Antia , Sarbani Basu