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The prototype for events that we call MFs - "March Fifth" events or "Magnetar Flares" - was observed on March 5, 1979. There is evidence that MFs are powered by catastrophic magnetic instabilities in ultramagnetized neutron stars. These…

Astrophysics · Physics 2009-11-06 Robert C. Duncan

The efficient release of magnetic energy in astrophysical plasmas, such as during solar flares, can in principle be achieved through magnetic diffusion, at a rate determined by the associated electric field. However, attempts at measuring…

High-resolution time series of sunspots have been obtained with the Swedish 1m Solar Telescope between 2003 and 2006 at different locations on the solar disc. Proper motions in seven different active regions have been studied. The analysis…

The 2011 outburst of Swift J1822.3--1606 was extraordinary; periodic modulations at the spin period of the underlying neutron star were clearly visible, remarkably similar to what is observed during the decaying tail of magnetar giant…

High Energy Astrophysical Phenomena · Physics 2015-09-29 Manoneeta Chakraborty , Ersin Gogus

The magnetar Swift J1555.2-5402 was discovered in outburst on 2021 June 3 by the Burst Alert Telescope on board the Swift satellite. Early X-ray follow-up revealed a spin period P~3.86 s, a period derivative Pdot~3e-11 s/s, dozens of short…

Observations of nearby star forming clouds with imaging X-ray telescopes have revealed that X-ray emission is elevated $10^1-10^4$ above main sequence levels in low-mass pre-main sequence (PMS) stars. The variability and spectral X-ray…

Astrophysics · Physics 2007-05-23 Eric D. Feigelson

The theory of cold, relativistic, magnetohydrodynamic outflows is generalized by the inclusion of an intense radiation source. In some contexts, such the breakout of a gamma-ray burst jet from a star, the outflow is heated to a high…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Matthew Russo , Christopher Thompson

The Sun and other cool stars harbouring outer convection zones manifest magnetic activity in their atmospheres. The connection between this activity and the properties of a deep-seated dynamo generating the magnetic flux is not well…

Solar and Stellar Astrophysics · Physics 2015-05-27 Emre Işık , Dieter Schmitt , Manfred Schüssler

Forming massive stars launch outflows of magnetic origin, which in fact serve as a marker for finding sites of massive star formation. However, both the theoretical and observational study of the mechanisms that intervene in the formation…

Solar and Stellar Astrophysics · Physics 2023-01-18 André Oliva , Rolf Kuiper

We present a study of molecular outflows using high-resolution mapping of the CO (1-0) line emission toward eight relatively nearby 6.7 GHz methanol masers, which are associated with massive star forming regions. Outflows were detected in…

Astrophysics · Physics 2008-11-26 Y. Xu , Z. -Q. Shen , J. Yang , X. W. Zheng , A. Miyazaki , K. Sunada , H. J. Ma , J. J. Li , J. X. Sun , C. C. Pei

Magnetar flares are highly energetic and rare events in which intense X and {\gamma}-ray emission is released from strongly magnetised neutron stars. The events are also accompanied by mass ejection from the neutron star. Fast radio bursts…

High Energy Astrophysical Phenomena · Physics 2026-03-18 Konstantinos N. Gourgouliatos

Vortex-type motions have been measured by tracking bright points in high-resolution observations of the solar photosphere. These small-scale motions are thought to be determinant in the evolution of magnetic footpoints and their interaction…

Solar and Stellar Astrophysics · Physics 2015-05-18 L. Balmaceda , S. Vargas Domínguez , J. Palacios , I. Cabello , V. Domingo

The twisted local magnetic field at the front or rear regions of the magnetic clouds (MCs) associated with interplanetary coronal mass ejections (ICMEs) is often nearly opposite to the direction of the ambient interplanetary magnetic field…

We consider possible geometries of magnetic fields in GRB outflows, and their evolution with distance from the source. For magnetically driven outflows, with an assumed ratio of magnetic to kinetic energy density of order unity, the field…

Astrophysics · Physics 2009-10-31 H. C. Spruit , F. Daigne , G. Drenkhahn

The detection of a short hard X-ray burst and an associated bright soft X-ray source by the Swift satellite in 2020 October heralded a new magnetar in outburst, SGR J1830-0645. Pulsations at a period of ~10.4 s were detected in prompt…

Magnetar bursts can be emitted by Alfv\'en waves growing in the outer magnetosphere to nonlinear amplitudes, $\delta B/B\sim 1$, and triggering magnetic reconnection. Similar magnetic flares should occur quasi-periodically in a magnetized…

High Energy Astrophysical Phenomena · Physics 2021-11-17 Andrei M. Beloborodov

We make a comparative analysis for two filaments that showed quite different activation in response to the flux emergence within the filament channels. The observations from the Solar Dynamics Observatory (SDO) and Global Oscillation…

Solar and Stellar Astrophysics · Physics 2015-08-06 Ting Li , Jun Zhang , Haisheng Ji

Aims. The aim of this paper is to consider relationship between the decay of sunspots and convection via the motion of the family of granules and how the diffusion mechanism of magnetic field operates in a decaying sunspot. Methods. We…

Solar and Stellar Astrophysics · Physics 2024-04-02 Chenxi Zheng , Thierry Roudier , Brigitte Schmieder , Guiping Ruan , Jean-Marie Malherbe , Yang Liu , Yao Chen , Wenda Cao

We have investigated the variation of magnetic helicity over a span of several days around the times of 11 X-class flares which occurred in seven active regions (NOAA 9672, 10030, 10314, 10486, 10564, 10696, and 10720) using the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Sung-Hong Park , Jeongwoo Lee , Gwang-Son Choe , Jongchul Chae , Hyewon Jeong , Guo Yang , Ju Jing , Haimin Wang

Rapid magnetic upflows in the quiet-Sun photosphere were recently uncovered from both SUNRISE/IMaX and Hinode/SOT observations. Here, we study magnetic upflow events (MUEs) from high-quality, high- (spatial, temporal, and spectral)…

Solar and Stellar Astrophysics · Physics 2015-09-07 S. Jafarzadeh , L. Rouppe van der Voort , J. de la Cruz Rodriguez