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Most studies of quasi-periodic pulsations in solar flares have identified characteristic periods in the 5 - 300s range. Due to observational limitations there have been few attempts to probe the < 5s period regime and understand the…

Solar and Stellar Astrophysics · Physics 2024-06-12 Andrew R. Inglis , Laura A. Hayes

The GOES M2-class solar flare, SOL2010-06-12T00:57, was modest in many respects yet exhibited remarkable acceleration of energetic particles. The flare produced an ~50 s impulsive burst of hard X- and \gamma-ray emission up to at least 400…

High Energy Astrophysical Phenomena · Physics 2017-02-22 Fermi GBM Collaboration , Fermi LAT Collaboration , B. R. Dennis , R. A. Schwartz , A. K. Tolbert

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 nature of quasi-periodic pulsations in solar flares is poorly constrained, and critically the general prevalence of such signals in solar flares is unknown. Therefore, we perform a large-scale search for evidence of signals consistent…

Solar and Stellar Astrophysics · Physics 2016-12-28 A. R. Inglis , J. Ireland , B. R. Dennis , L. A. Hayes , P. T. Gallagher

In the last four decades it has been observed that solar flares show quasi-periodic pulsations (QPPs) from the lowest, i.e. radio, to the highest, i.e. gamma-ray, part of the electromagnetic spectrum. To this day, it is still unclear which…

Short timescale flux variations are closely related to the energy release process of magnetic reconnection during solar flares. Radio light curves at 1, 2, 3.75, 9.4, and 17 GHz of 209 flares observed by the Nobeyama Radio Polarimeter from…

Solar and Stellar Astrophysics · Physics 2020-06-04 Wang Lu , Liu Si-ming , Ning Zong-jun

We present the detections of 19 solar flares detected in high-energy gamma rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first four years of operation. Interestingly, all flares are associated with fairly fast…

High Energy Astrophysical Phenomena · Physics 2017-02-22 LAT collaboration

The Fermi Large Area Telescope (LAT) observed two bright X-class solar flares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission…

High Energy Astrophysical Phenomena · Physics 2017-02-22 LAT collaboration

We present an analysis of intermittent processes occurred during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and have been a…

Solar and Stellar Astrophysics · Physics 2016-06-22 C. Guillermo Giménez de Castro , Paulo J. A. Simões , Jean-Pierre Raulin , Odilon M. Guimarães

Solar small scale microwave bursts (SMBs), including microwave dot, spike, and narrow band type III bursts, are characterized with very short timescales, narrow frequency bandwidth, and very high brightness temperatures. Based on…

Solar and Stellar Astrophysics · Physics 2015-06-16 Baolin Tan

The energy and spectral shape of radio bursts may help us understand the generation mechanism of solar eruptions, including solar flares, CMEs, eruptive filaments, and various scales of jets. The different kinds of flares may have different…

Solar and Stellar Astrophysics · Physics 2022-01-05 Chengming Tan , Karl-Ludwig Klein , Yihua Yan , Satoshi Masuda , Baolin Tan , Jing Huang , Guowu Yuan

Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, there are often multiple, temporally and spatially separated…

Solar and Stellar Astrophysics · Physics 2020-12-02 Rohit Sharma , Marina Battaglia , Yingjie Luo , Bin Chen , Sijie Yu

We explore the quasi-periodic pulsations (QPPs) with multiple periods in hard X-ray (HXR) emission from Fermi/GBM during the impulsive phase of solar flare (SOL2014-09-10). The completely new observational result is that the shorter periods…

Solar and Stellar Astrophysics · Physics 2017-07-19 Dong Li , Qingmin Zhang

This paper presents the gamma-ray spectral and timing results from the long-term regular observations of Mrk 421 with the Large Area Telescope (LAT) onboard Fermi during 2008 August - 2023 August. We discerned six periods the relatively…

High Energy Astrophysical Phenomena · Physics 2025-03-05 B. Kapanadze , A. Gurchumelia , M. Aller

We considered 18 solar flares observed between June 2010 and July 2012, in which high energy >100 MeV {\gamma}-emission was registered by the Large Area Telescope (LAT) aboard FermiGRO. We examined for these {\gamma}-events soft X-ray…

High Energy Astrophysical Phenomena · Physics 2015-09-02 Alexei Struminsky , Weiqun Gan

Solar flares are observed and classified according to their intensity measured with the GOES X-ray Sensors. We show that the duration of a flare, as measured by the full width at half maximum (FWHM) in GOES is not related to the size of the…

Solar and Stellar Astrophysics · Physics 2019-04-10 Jeffrey W. Reep , Kalman J. Knizhnik

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…

Based on a 10 years sample of gamma-ray flares of FSRQs collected with FERMI and AGILE, I report on this proceeding the advance on a statistical study of variability for a sample of more than 300 FSRQs. I will focus on waiting time between…

High Energy Astrophysical Phenomena · Physics 2025-07-08 Luigi Pacciani

We searched for superflares on solar-type stars using Kepler data with 1 min sampling in order to detect superflares with short duration. We found 187 superflares on 23 solar-type stars whose bolometric energy ranges from the order of…

Solar and Stellar Astrophysics · Physics 2015-05-11 Hiroyuki Maehara , Takuya Shibayama , Yuta Notsu , Shota Notsu , Satoshi Honda , Daisaku Nogami , Kazunari Shibata

A new solar burst emission spectral component has been found showing sub-THz fluxes increasing with frequency, spectrally separated from the well known microwave component. Rapid pulsations are found present in all events observed at the…

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