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aims: We study the recently discovered twisting motion of bright penumbral filaments with the aim of constraining their geometry and the associated magnetic field. methods: A large sunspot located $40\degr$ from disk center was observed at…

Astrophysics · Physics 2009-11-13 V. Zakharov , J. Hirzberger , T. L. Riethmueller , S. K. Solanki , P. Kobel

The various mechanisms of magneto-convective energy transport determines the structure of sunspots and active regions. We characterise the appearance of light bridges and other fine-structure details and elaborate on their…

The spatially resolved broad-band spectroscopy with Very Long Baseline Interferometry (VLBI) is one of the few methods that can probe the physical conditions inside blazar jets. We report on measurements of the magnetic field strength in…

Astrophysics of Galaxies · Physics 2010-01-19 K. V. Sokolovsky , Y. Y. Kovalev , A. P. Lobanov , T. Savolainen , A. B. Pushkarev , M. Kadler

When the polarimetric sensitivity and the angular resolution exceed a threshold, magnetic fields show up almost everywhere on the solar surface. Here I revise the observational properties of the weakest polarization signals, which appear in…

Astrophysics · Physics 2007-05-23 J. Sanchez Almeida

Light walls, as ensembles of oscillating bright structures rooted in sunspot light bridges, have not been well studied, although they are important for understanding sunspot properties. Using the Interface Region Imaging Spectrograph and…

Solar and Stellar Astrophysics · Physics 2017-07-19 Shuhong Yang , Jun Zhang , Robertus Erdélyi , Yijun Hou , Xiaohong Li , Limei Yan

We present a study of unusually bright single pulses (BSPs) from a millisecond pulsar in an ablating binary system, B1744-24A, based on several multi-orbit observations with the Green Bank Telescope. These pulses come predominantly in time…

High Energy Astrophysical Phenomena · Physics 2019-06-11 Anna Bilous , Scott Ransom , Paul Demorest

Solar magnetic synoptic charts obtained by NSO/Kitt Peak and SOHO/MDI are analyzed for studying the appearance of bipolar magnetic regions (BMRs) during solar minima. As a result, we find the emergence of long-lived BMRs has three typical…

Astrophysics · Physics 2009-11-13 Wenbin Song , Xueshang Feng

For groups of photospheric magnetic fields differing in strength the time averaged synoptic maps were obtained on the basis of the National Solar Observatory Kitt Peak data (1976-2003). The latitudinal profiles of magnetic field fluxes were…

Solar and Stellar Astrophysics · Physics 2018-03-21 Elena Vernova , Marta Tyasto , Dmitrii Baranov

Umbral flashes are manifestations of magnetoacoustic shocks in the solar chromosphere. These phenomena are thought to influence the evolution of chromospheric umbral magnetic fields. However, the impact of these shocks on inferred…

Solar and Stellar Astrophysics · Physics 2026-03-13 Hirdesh Kumar , Tobias Felipe , Christoph Kuckein , S. J. González Manrique , A. Asensio Ramos

The main-sequence mercury-manganese (HgMn) stars are known to exhibit large overabundances of exotic elements and, similar to magnetic Ap/Bp stars, are spectrum variables, implying the presence of an inhomogeneous element distribution over…

Solar and Stellar Astrophysics · Physics 2020-04-29 S. Hubrig , S. P. Jarvinen , H. Korhonen , I. Ilyin , M. Schöller , E. Niemczura , S. D. Chojnowski

The properties of magnetic fields forming an extended plage region in AR 10953 were investigated. Stokes spectra of the Fe I line pair at 6302 \AA recorded by the spectropolarimeter aboard the Hinode satellite were inverted using the SPINOR…

Solar and Stellar Astrophysics · Physics 2015-03-25 D. Buehler , A. Lagg , S. K. Solanki , M. van Noort

We analyze spectropolarimetric observations of the chromospheric Ca II 8542 A line taken by the Interferometric Bidimensional Spectrometer (IBIS) at the Dunn Solar Telescope. The data were observed on 2012 January 29 for the NOAA active…

Solar and Stellar Astrophysics · Physics 2017-12-20 Ali G. A. Abdelkawy , Abdelrazek M. K. Shaltout , M. M. Beheary , T. A. Schad

Sunspot penumbrae show high-velocity patches along the periphery. The high-velocity downflow patches are believed to be the return channels of the Evershed flow. We aim to investigate their structure in detail using Hinode SOT/SP…

Solar and Stellar Astrophysics · Physics 2015-06-16 Michiel van Noort , Andreas Lagg , Sanjiv Tiwari , Sami Solanki

The equilibrium structure of sunspots depends critically on its magnetic topology and is dominated by magnetic forces. Tension force is one component of the Lorentz force which balances the gradient of magnetic pressure in force-free…

Space Physics · Physics 2015-05-19 P. Venkatakrishnan , Sanjiv Kumar Tiwari

The vertical component of the magnetic field ($B_\perp$) was found to reach a constant value at the umbra-penumbra boundary of stable sunspots in a recent statistical study of Hinode/SP data. The objective of this work is to verify the…

Solar and Stellar Astrophysics · Physics 2020-07-01 P. Lindner , R. Schlichenmaier , N. Bello González

Studying the emergence of magnetic fields is essential for understanding the physical mechanisms behind various phenomena in the solar atmosphere. Most importantly, the emerging fields offer valuable insights into how energy and mass are…

Solar and Stellar Astrophysics · Physics 2025-08-28 Milan Gošić , Viggo H. Hansteen , Alberto Sainz Dalda , Bart De Pontieu , Luc H. M. Rouppe van der Voort

Optical and infrared continuum polarization from the interstellar medium is known to generally be due to irregular dust grains aligned with the magnetic field. This provides an important tool to probe the geometry and strength of those…

Astrophysics of Galaxies · Physics 2019-03-20 Ilija Medan , B-G Andersson

We used the flux calibrated images through the Broad Band Filter Imager and Stokes Polarimeter data obtained with the Solar Optical Telescope onboard the Hinode spacecraft to study the properties of bright points in and around the sunspots.…

Solar and Stellar Astrophysics · Physics 2015-05-18 Debi Prasad Choudhary , Toshifumi Shimizu

The penumbra of a sunspot is a fascinating phenomenon featuring complex velocity and magnetic fields. It challenges both our understanding of radiative magneto-convection and our means to measure and derive the actual geometry of the…

Astrophysics · Physics 2009-11-13 Rolf Schlichenmaier

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of…

Astrophysics · Physics 2008-11-26 Itahiza Dominguez Cerdena , Jorge Sanchez Almeida , Franz Kneer