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Related papers: Persistent Quasi-Periodic Pulsations During a Larg…

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We analyse the 30 October, 2004, X1.2/SF solar event that occurred in AR 10691 (N13 W18) at around 11:44 UT. Observations at 212 and 405 GHz of the Solar Submillimeter Telescope (SST), with high time resolution (5 ms), show an intense…

Context. The dynamics of the flaring loops in active region (AR) 11429 are studied. The observed dynamics consist of several evolution stages of the flaring loop system during both the ascending and descending phases of the registered…

We present a detailed multi-wavelength analysis and interpretation of the evolution of an M7.6 flare on October 24, 2003. The X-ray observations of the flare taken from the RHESSI spacecraft reveal two phases of the flare evolution. The…

Recent X-ray observations have discovered a class of periodic X-ray flares in galactic nuclei known as quasi-periodic eruptions (QPEs). A promising explanation of QPEs is an emission produced when a stellar-mass object orbiting a central…

High Energy Astrophysical Phenomena · Physics 2025-05-16 Tomoya Suzuguchi , Hidetoshi Omiya , Hiroki Takeda

Giant flares from soft gamma-ray repeaters (SGRs) are one of the most violent phenomena in neutron stars. Quasi-periodic oscillations (QPOs) with frequencies ranging from 18 to 1840 Hz have been discovered in the tails of giant flares from…

Astrophysics · Physics 2008-10-14 Bo Ma , Xiang-Dong Li , P. F. Chen

In the present paper, we analyze three energetic X-ray flares from the active RS CVn binary HR 1099 using data obtained from XMM-Newton. The flare duration ranges from 2.8 to 4.1 h, with e-folding rise and decay times in the range of 27 to…

Solar and Stellar Astrophysics · Physics 2024-11-19 Shweta Didel , Jeewan C Pandey , A. K. Srivastava

Solar flares are complex phenomena emitting all types of electromagnetic radiation, and accelerating particles on timescales of minutes, converting magnetic energy to thermal, radiative, and kinetic energy through magnetic reconnections. As…

Solar and Stellar Astrophysics · Physics 2023-09-01 Crisel Suarez , Christopher S. Moore

We report the discovery of quasi-periodic oscillations (QPOs) in the High Mass X-ray Binary (HMXB) pulsar LMC X-4 in its non-flaring (persistent) state using observations with XMM-Newton. In addition to the 74 mHz coherent pulsations, the…

High Energy Astrophysical Phenomena · Physics 2022-03-30 Ketan Rikame , Biswajit Paul , Pragati Pradhan , KT Paul

Using Gaussian process methods, we analyzed the light curves of three extreme solar X-ray flares observed by the RHESSI satellite. Their variability characteristics were then compared with those of HXMT-HE X-ray burst (XRB; in SGR…

High Energy Astrophysical Phenomena · Physics 2025-12-15 Haiyun Zhang , Dahai Yan , Lijuan Dong , Ping Zhang , Ruijing Tang , Jianeng Zhou , Lian Tao , Li Zhang , Niansheng Tang

The observational analysis is performed to study the excitation mechanism and the propagation properties of a quasi-periodic fast-propagating (QFP) magnetosonic wave. The QFP wave was associated with the eruption of a nearby mini-filament…

Solar and Stellar Astrophysics · Physics 2018-05-02 Yuandeng Shen , Tengfei Song , Yu Liu

We explored simultaneous observations of chromospheric evaporation and condensation during the impulsive phase of a C6.7 flare on 9 May 2019. The solar flare was simultaneously observed by multiple instruments, i.e., the New Vacuum Solar…

Solar and Stellar Astrophysics · Physics 2022-02-16 Dong Li , Zhenxiang Hong , Zongjun Ning

Understanding the relationship among different emission components plays an essential role in the study of particle acceleration and energy conversion in solar flares. In flares where gradual and impulsive emission components can be readily…

Solar and Stellar Astrophysics · Physics 2015-06-15 Siming Liu , Youping Li , Lyndsay Fletcher

We analyzed and modeled an M1.2 non-eruptive solar flare on 2011 September 9. The flare exhibits a strong late-phase peak of the warm coronal emissions ($\sim$3~MK) of extreme-ultraviolet (EUV), with peak emission over 1.3 times that of the…

Solar and Stellar Astrophysics · Physics 2018-08-29 Yu Dai , Mingde Ding , Weiguo Zong , Kai E. Yang

We present a multiwavelength study of the X-class flare, which occurred in active region (AR) NOAA 11339 on 3 November 2011. The EUV images recorded by SDO/AIA show the activation of a remote filament (located north of the AR) with…

Solar and Stellar Astrophysics · Physics 2015-06-16 Pankaj Kumar , K. S. Cho

In this paper, we report our multiwavelength observations of the C3.1 circular-ribbon flare SOL2015-10-16T10:20 in AR 12434. The flare consisted of a circular flare ribbon (CFR), an inner flare ribbon (IFR) inside, and a pair of short…

Solar and Stellar Astrophysics · Physics 2016-11-23 Q. M. Zhang , D. Li , Z. J. Ning

Context. Hard X-ray (HXR) spikes refer to fine time structures on timescales of seconds to milliseconds in high-energy HXR emission profiles during solar flare eruptions. Aims. We present a preliminary statistical investigation of temporal…

Solar and Stellar Astrophysics · Physics 2015-06-11 J. X. Cheng , J. Qiu , M. D. Ding , H. Wang

The Fermi-Large Area Telescope (LAT) detection of the X8.2 GOES class solar flare of 2017 September 10 provides for the first time observations of a long duration high-energy gamma-ray flare associated with a Ground Level Enhancement (GLE).…

High Energy Astrophysical Phenomena · Physics 2018-09-26 Nicola Omodei , Melissa Pesce-Rollins , Francesco Longo , Alice Allafort , Säm Krucker

Slow Long Duration Events (SLDEs) are flares characterized by long duration of rising phase. In many such cases impulsive phase is weak with lack of typical short-lasting pulses. Instead of that smooth, long-lasting Hard X-ray (HXR)…

Solar and Stellar Astrophysics · Physics 2015-05-27 Urszula Bak-Steslicka , Tomasz Mrozek , Sylwester Kolomanski

In this letter, we present a spectacular eruptive flare (X8.2) associated with a coronal mass ejection (CME) on 2017 September 10 at the west limb of the Sun. A flux rope eruption is followed by the inflow, the formation of a current sheet…

Solar and Stellar Astrophysics · Physics 2018-02-14 X. L. Yan , L. H. Yang , Z. K. Xue , Z. X. Mei , D. F. Kong , J. C. Wang , Q. L. Li

We present the analyses of intense X-ray flares detected on the active fast rotator AB Dor using observations from the XMM-Newton. A total of 21 flares are detected, and 13 flares are analysed in detail. The total X-ray energy of these…

Solar and Stellar Astrophysics · Physics 2023-10-23 Shweta Didel , Jeewan C. Pandey , A. K. Srivastava , Gurpreet Singh