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Category/Subcategory: Natural Sciences/Astronomy

Spicules and their on-disk counterparts - the main driver for solar chromospheric heating?

Author: Klaus Gerhard Puschmann
The question how the outer solar atmosphere is heated from solar photospheric temperatures of about 5800K up to solar chromospheric and coronal temperatures of about 20.000K and millions of degrees respectively, remained without a ... more

Views: 959

Meridional Circulation and Global Solar Oscillations

Author: Markus Roth
We investigate the influence of large-scale meridional circulation on solar p-modes by quasi-degenerate perturbation theory, as proposed by Lavely and Ritzwoller (1992). As an input flow we use various models of stationary meridio ... more

Views: 486

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: 425

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: 390

Observational evidence for variations of the acoustic cutoff frequency with height in the solar atmosphere

Author: Aneta Wisniewska
Direct evidence for the existence of an acoustic cuto frequency in the solar atmosphere is given by observations performed by using the HELioseismological Large Regions Interferometric DEvice operating on the Vacuum Tower Teles ... more

Views: 349

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: 386

Modelling solar and stellar brightness variabilities

Author: Alexander Shapiro
Total and spectral solar irradiance, TSI and SSI, have been measured from space since 1978. This is accompanied by the development of models aimed at replicating the observed variability by relating it to solar surface magnetism. ... more

Views: 384

Surface waves in solar granulation observed with Sunrise

Author: Markus Roth
Solar oscillations are expected to be excited by turbulent flows in the intergranular lanes near the solar surface. Time series recorded by the IMaX instrument aboard the {\sc Sunrise} observatory reveal solar oscillations at hig ... more

Views: 323

Global helioseismic evidence for a deeply penetrating Solar meridional flow consisting of multiple flow cells

Author: Markus Roth
We use a novel global helioseismic analysis method to infer the meridional flow in the deep Solar interior. The method is based on the perturbation of eigenfunctions of Solar p modes due to meridional flow. We apply this method ... more

Views: 674

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: 430