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Related papers: The Low-Frequency Solar Corona in Circular Polariz…

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Tomography of the solar corona can provide cruicial constraints for models of the low corona, unique information on changes in coronal structure and rotation rates, and a valuable boundary condition for models of the heliospheric solar…

Instrumentation and Methods for Astrophysics · Physics 2015-09-11 Huw Morgan

Potential Field Source Surface (PFSS) models are widely used to study the solar corona and form the basis for solar wind forecasting, yet often fail to reproduce observed properties of coronal holes. We analyze 702 observed coronal holes…

Solar and Stellar Astrophysics · Physics 2026-01-19 Stephan G. Heinemann , Jens Pomoell , Manuela Temmer

Lyne & Manchester (1988) identified a group of some 50 pulsars they called "partial cones" which they found difficult to classify and interpret. They were notable for their asymmetric average profiles and asymmetric polarization…

Astrophysics of Galaxies · Physics 2015-05-20 Dipanjan Mitra , Joanna. M. Rankin

For the first time, a multi-wave research of oscillation dynamics in a solar facula from its birth to decay was carried out. We performed spectral observations of active region NOAA 12744 at Horizontal Solar Telescope of the Sayan Solar…

Solar and Stellar Astrophysics · Physics 2020-08-26 Andrei Chelpanov , Nikolai Kobanov

Stellar coronae are believed to be the main birthplace of various stellar magnetic activities. However, the structures and properties of stellar coronae remain poorly understood. Using the Space Weather Modelling Framework with the…

Sun-as-a-star coronal plasma composition, derived from full-Sun spectra, and the F10.7 radio flux (2.8 GHz) have been shown to be highly correlated (r = 0.88) during solar cycle 24. However, this correlation becomes nonlinear during…

We use microwave imaging observations from the Nobeyama Radioheliograph at 17 GHz for long-term studies of solar activity. In particular, we use the polar and low-latitude brightness temperatures as proxies to the polar magnetic field and…

Solar and Stellar Astrophysics · Physics 2018-08-15 N. Gopalswamy , P. Makela , S. Yashiro , S. Akiyama

The general model for incoherent synchrotron radiation has long been known, with the first theory being published by Westfold in $1959$ and continued by Westfold and Legg in $1968$. When this model was first developed it was applied to…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Diarmaid de Búrca , Andrew Shearer

We completed observations with the Effelsberg 100-m radio telescope to measure the polarised emission from a complete sample of Compact Steep-Spectrum sources. We observed the sources at four different frequencies. We complemented these…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 F. Mantovani , K. -H. Mack , F. M. Montenegro-Montes , A. Rossetti , A. Kraus

How and where are coronal loops rooted in the solar lower atmosphere? The details of the magnetic environment and its evolution at the footpoints of coronal loops are crucial to understanding the processes of mass and energy supply to the…

We present a comprehensive radio polarization study of the Perseus molecular cloud using wideband L-band observations from the Karl G. Jansky Very Large Array. Our survey covers $\sim13.8$~deg$^2$ with a mean Stokes~$I$ sensitivity of…

Astrophysics of Galaxies · Physics 2026-02-23 Haleh Hajizadeh , Jeroen Stil , René Plume , Mehrnoosh Tahani , Preshanth Jagannathan

We present results of multifrequency polarimetric VLBA observations of 34 compact radio sources. The observations are part of a large survey undertaken to identify CSOs Observed in the Northern Sky (COINS). Based on VLBI continuum surveys…

Astrophysics · Physics 2007-05-23 A. B. Peck , G. B. Taylor

This work aims to understand the behavior of non-linear waves in the vicinity of a coronal null point. In previous works we have showed that high frequency waves are generated in such magnetic configuration. This paper studies those waves…

Solar and Stellar Astrophysics · Physics 2017-06-07 I. C. Santamaria , E. Khomenko , M. Collados , A. de Vicente

We present sensitive ($\sim$9 $\mu$Jy), sub-arcsecond resolution radio continuum observations at 9.0 GHz (3.3 cm) and 14.0 GHz (2.1 cm) obtained with the Karl G. Jansky Very Large Array (VLA) toward the nearby Coronet Cluster in Corona…

A technique is described for measuring electrical currents in the solar corona. It uses radioastronomical polarization measurements of a spatially-extended radio source viewed through the corona. The observations yield the difference in the…

Astrophysics · Physics 2009-11-13 Steven R. Spangler

We report on full-Stokes L-band observations of 98 MeerKAT calibration sources. Linear polarization is detected in 71 objects above a fractional level of 0.2\%. We identify ten sources with strong fractional linear polarization and low…

Astrophysics of Galaxies · Physics 2024-05-24 A. R. Taylor , L. S. Legodi

Large coronal loops around one solar radius in altitude are an important connection between the solar wind and the low solar corona. However, their plasma properties are ill-defined as standard X-ray and UV techniques are not suited to…

Solar and Stellar Astrophysics · Physics 2023-02-01 Jinge Zhang , Hamish A. S. Reid , Vratislav Krupar , Pietro Zucca , Bartosz Dabrowski , Andrzej Krankowski

The rare intermittent pulsars pose some of the most challenging questions surrounding the pulsar emission mechanism, but typically have relatively minimal low-frequency ($\lesssim$ 300 MHz) coverage. We present the first low-frequency…

Efforts are underway to use high-precision timing of pulsars in order to detect low-frequency gravitational waves. A limit to this technique is the timing noise generated by dispersion in the plasma along the line of sight to the pulsar,…

High Energy Astrophysical Phenomena · Physics 2022-02-04 P. Kumar , S. M. White , K. Stovall , J. Dowell , G. B. Taylor

We report observations of solar spicules at millimeter wavelengths (mm-$\lambda$) using the Atacama Large Millimeter/submillimeter Array (ALMA). These are supplemented by observations in optical (O), ultraviolet (UV) and extreme ultraviolet…

Solar and Stellar Astrophysics · Physics 2025-04-09 T. S. Bastian , C. Alissandrakis , A. Nindos , M. Shimojo , S. M. White