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	No pulsed radio emission during a bursting phase of a Galactic magnetar 期刊论文 OAI收割 Nature, 2020, 卷号: 587, 页码: 63-65 作者: HXMT \| 收藏 \| 浏览/下载：46/0 \| 提交时间：2022/02/08 Astrophysics - High Energy Astrophysical Phenomena Abstract: Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances^1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources^4-13, but no convincing evidence has been collected so far¹⁴. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft íray bursts¹⁵. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft íray/hard-X-ray flare^18-21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-íray repeater (SGR) bursts were detected in íray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.
	GRB 200415A: A Short Gamma-Ray Burst from a Magnetar Giant Flare? 期刊论文 OAI收割 The Astrophysical Journal, 2020, 卷号: 899, 页码: 106 作者: HXMT \| 收藏 \| 浏览/下载：41/0 \| 提交时间：2022/02/08 Gamma-ray bursts Soft gamma-ray repeaters Magnetars Gamma-ray transient sources 629 1441 992 1853 Astrophysics - High Energy Astrophysical Phenomena Abstract: The giant flares of soft gamma-ray repeaters (SGRs) have long been proposed to contribute to at least a subsample of the observed short gamma-ray bursts (GRBs). In this paper, we perform a comprehensive analysis of the high-energy data of the recent bright short GRB 200415A, which was located close to the Sculptor galaxy. Our results suggest that a magnetar giant flare provides the most natural explanation for most observational properties of GRB 200415A, including its location, temporal and spectral features, energy, statistical correlations, and high-energy emissions. On the other hand, the compact star merger GRB model is found to have difficulty reproducing such an event in a nearby distance. Future detections and follow-up observations of similar events are essential to firmly establish the connection between SGR giant flares and a subsample of nearby short GRBs.
	Estimating horizontal electric current in solar active regions 期刊论文 OAI收割 SOLAR PHYSICS, 1998, 卷号: 182, 期号: 2, 页码: 365-379 作者: Ji, HS; Song, MT; Li, XQ; Hu, FM 收藏 \| 浏览/下载：29/0 \| 提交时间：2013/02/05 FREE MAGNETIC-FIELDS FLARE PHENOMENA MORPHOLOGY NOAA-6659 VECTOR JUNE