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We present a large-scale view of the magnetic field in the central 2deg * 2deg region of our Galaxy. The polarization of point sources has been measured in the J, H, and Ks bands using the near-infrared polarimetric camera SIRPOL on the 1.4…

Sunspots are dark spots on the solar surface associated with strong magnetic fields. The number, area, and brightness of sunspots are supposed to reflect the intensity of the solar magnetic fields and are often used as proxies for their…

Solar and Stellar Astrophysics · Physics 2015-06-16 K. Georgieva , B. Kirov , Yu. A. Nagovitsyn

We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies are obtained by tracking the temporal…

Solar and Stellar Astrophysics · Physics 2017-12-13 D. Salabert , R. A. García , A Jiménez , L. Bertello , E. Corsaro , P. L. Pallé

The solar magnetism is no more considered as a purely superficial phenomenon. The SoHO community has shown that the length of the solar cycle depends on the transition region between radiation and convection. Nevertheless, the internal…

We point out that polarization measurements as planned for the upcoming PLANCK mission can significantly enhance the accuracy of cosmic parameter estimation compared to the temperature anisotropy spectrum alone. In order to illustrate this,…

Astrophysics · Physics 2007-05-23 Pavel Naselsky , Jens Schmalzing , Jesper Sommer-Larsen , Steen Hannested

We study the magnetic flux carried by pores located outside active regions with sunspots and investigate their possible contribution to the reversal of the global magnetic field of the Sun. We find that they contain a total flux of…

Solar and Stellar Astrophysics · Physics 2016-02-10 M. Svanda , A. S. Brun , Th. Roudier , L. Jouve

We have finished the 6cm polarization survey of the Galactic plane using the Urumqi 25m radio telescope. It covers 10deg<l<230deg in Galactic longitude and |b| <5deg in Galactic latitude. The new polarization maps not only reveal new…

Astrophysics of Galaxies · Physics 2015-06-04 J. L. Han , W. Reich , X. H. Sun , X. Y. Gao , L. Xiao , W. B. Shi , P. Reich , R. Wielebinski

In recent years, the development of spectropolarimetric techniques deeply modified our knowledge of stellar magnetism. In the case of solar-type stars, the challenge is to measure a geometrically complex field and determine its evolution…

Astrophysics · Physics 2007-05-23 P. Petit

The solar activity, which is driven by a variable magnetic field, exhibits changes along several time scales, the 11-year being the most known. In addition to the SunSpot Number, the Ca II K index and the Mg II index are indices widely…

Solar and Stellar Astrophysics · Physics 2024-05-28 Raffaele Reda , Valentina Penza

Patterns of the magnetic signature of ionospheric currents, generated from an empirical model based on satellite observations, are used to build a statistical correlation based model for ionospheric fields. In order to stabilize the…

Geophysics · Physics 2025-02-14 K. Ferrat , M. Schanner , V. Lesur , M. Holschneider , C. Stolle , J. Baerenzung

Solar filaments are well-known tracers of polarity inversion lines that separate two opposite magnetic polarities on the solar photosphere. Because observations of filaments began long before the systematic observations of solar magnetic…

Machine Learning · Computer Science 2024-05-13 V. Kisielius , E. Illarionov

Dust polarization observations are a powerful, practical tool to probe the geometry (and to some extent, the strength) of magnetic fields in star-forming regions. In particular, Planck polarization data have revealed the importance of…

Ahead-of-time forecasting of the output power of power plants is essential for the stability of the electricity grid and ensuring uninterrupted service. However, forecasting renewable energy sources is difficult due to the chaotic behavior…

Computer Vision and Pattern Recognition · Computer Science 2023-10-27 Anas Al-lahham , Obaidah Theeb , Khaled Elalem , Tariq A. Alshawi , Saleh A. Alshebeili

Axion helioscopes search for solar axions and axion-like particles via inverse Primakoff conversion in strong laboratory magnets pointed at the Sun. Anticipating the detection of solar axions, we determine the potential for the planned…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-28 Ciaran A. J. O'Hare , Andrea Caputo , Alexander J. Millar , Edoardo Vitagliano

If the alpha effect plays a role in the generation of the Sun's magnetic field, the field should show evidence of magnetic helicity of opposite signs at large and small length scales. Measuring this faces two challenges: (i) in weak-field…

Solar and Stellar Astrophysics · Physics 2019-09-30 Axel Brandenburg

Variations in the solar wind density introduce variable delays into pulsar timing observations. Current pulsar timing analysis programs only implement simple models of the solar wind, which not only limit the timing accuracy, but can also…

Astrophysics · Physics 2009-11-13 X. P. You , G. B. Hobbs , W. A. Coles , R. N. Manchester , J. L. Han

The continuous observation of the magnetic field by Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI) produces numerous image sequences in time and space. These sequences provide data support for predicting the…

Solar and Stellar Astrophysics · Physics 2021-06-23 Liang Bai , Yi Bi , Bo Yang , Jun-Chao Hong , Zhe Xu , Zhen-Hong Shang , Hui Liu , Hai-Sheng Ji , Kai-Fan Ji

To reproduce the weak magnetic field on the polar caps of the Sun observed during the declining phase of cycle 23 poses a challenge to surface flux transport models since this cycle has not been particularly weak. We use a well-calibrated…

Solar and Stellar Astrophysics · Physics 2015-05-27 Jie Jiang , Robert H. Cameron , Dieter Schmitt , Manfred Schuessler

When observed in quiet regions close to the solar limb, many strong resonance lines show conspicuous linear polarization signals, produced by scattering processes, with extended wing lobes. Recent studies indicate that, contrary to what was…

Solar and Stellar Astrophysics · Physics 2022-01-12 Emilia Capozzi , Ernest Alsina Ballester , Luca Belluzzi , Javier Trujillo Bueno

Phase-resolved observations of the solar-type star Ksi Bootis A were obtained using the NARVAL spectropolarimeter at the Telescope Bernard Lyot (Pic du Midi, France) during years 2007, 2008, 2009 and 2010. The data sets enable us to study…