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Category/Subcategory: Natural Sciences/Astronomy

Validation of Spherical Born Approximation Sensitivity Functions for Measuring Deep Solar Meridional Flow

Author: Vincent Böning
Accurate measurements of deep solar meridional flow are of vital interest for understanding the solar dynamo. In this paper, we validate a recently developed method for obtaining sensitivity functions (kernels) for travel-time mea ... more

Views: 527

VARIATION OF ACOUSTIC CUTOFF PERIOD WITH HEIGHT IN THE SOLAR ATMOSPHERE: THEORY VERSUS OBSRVETIONS

Author: Aneta Wisniewska
Recently Wiśniewska et al. demonstrated observationally how the acoustic cutoff frequency varies with height in the solar atmosphere including the upper photosphere and the lower and middle chromosphere, and showed that the obser ... more

Views: 446

Stellar magnetic activity and variability of oscillation parameters - An investigation of 24 solar-like stars observed by Kepler

Author: René Kiefer
Context. The Sun and solar-like stars undergo activity cycles for which the underlying mechanisms are not well understood. The oscillations of the Sun are known to vary with its activity cycle and these changes provide diagnostics ... more

Views: 530

Sensitivity Kernels for Flows in Time-Distance Helioseismology: Extension to Spherical Geometry

Author: Vincent Böning
We extend an existing Born approximation method for calculating the linear sensitivity of helioseismic travel times to flows from Cartesian to spherical geometry. This development is necessary for using the Born approximation for ... more

Views: 636

The Importance of Long-term Synoptic Observations and Data Sets for Solar Physics and Helioseismology

Author: Markus Roth
A casual single glance at the Sun would not lead an observer to conclude that it varies. The discovery of the 11-year sunspot cycle was only made possible through systematic daily observations of the Sun over 150 years and even to ... more

Views: 479

Verification of the helioseismic Fourier-Legendre analysis for meridional flow measurements

Author: Markus Roth
{Measuring the Sun's internal meridional flow is one of the key issues of helioseismology. Using the Fourier-Legendre analysis is a technique for addressing this problem.} {We validate this technique with the help of artificial ... more

Views: 433

Experimental results for infrared aberration tracking using a correlation algorithm on two star extended field

Author: Narsireddy Anugu
We report an experimental results of different correlation algorithms for an extended source wavefront sensor.

Views: 478

AN UPDATE ON THE MOPRA SOUTHERN GALACTIC PLANE CO SURVEY

Author: Michael Burton
The 22 m diameter Mopra telescope in Australia is being used to undertake an improved survey of the CO J = 1{0 line at 3mm along the 4th quadrant of the Galaxy, achieving an order of magnitude better spatial and spectral resolut ... more

Views: 480

Measurement of the VLT pupil motions using a 2 × 2 lenslet evaluated aberrations

Author: Narsireddy Anugu
We present the telescope pupil tracking strategy for the GRAVITY interferometer.

Views: 439