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We present a detailed analysis of a superflare on the active M dwarf star AD Leonis. The event presents a rare case of a stellar flare observed simultaneously in X-rays (with XMM-Newton) and in optical (with the Transiting Exoplanet Survey…

Solar and Stellar Astrophysics · Physics 2022-11-30 B. Stelzer , M. Caramazza , St. Raetz , C. Argiroffi , M. Coffaro

The presence of flare related acoustic emission (sunquakes) in some flares represents a severe challenge to our current understanding of flare energy transport processes. We present a comparison of new spectral observations from Hinode's…

Solar and Stellar Astrophysics · Physics 2015-10-14 Sarah A. Matthews , Louise K. Harra , Sergei Zharkov , Lucie M. Green

We investigate the characteristics of bright flares for a sample of supergiant fast X-ray transients and their relation to the orbital phase. We have retrieved all Swift/BAT Transient Monitor light curves, and collected all detections in…

We present analysis of a GOES C1-class flare from 2022 September 6, which was jointly observed as occulted by Nuclear Spectroscopic Telescope ARray (NuSTAR) and on-disk by Spectrometer/Telescope for Imaging X-rays (STIX). NuSTAR observed…

Surface granulation can be predicted with the mass, metallicity, and frequency of maximum power of a star. Using the orders-of-magnitude larger APOGEE-Kepler sample, we recalibrate the relationship fit by Corsaro et al. (2017) for…

Solar and Stellar Astrophysics · Physics 2019-10-09 Jamie Tayar , Keivan G. Stassun , Enrico Corsaro

The Space Telescope Imaging Spectrograph (STIS) has measured the flux for Sirius from 0.17--1.01~$\mu$m on the \emph{HST} White Dwarf scale. Because of the cool debris disk around Vega, Sirius is commonly recommended as the primary IR flux…

Instrumentation and Methods for Astrophysics · Physics 2014-03-28 R. C. Bohlin

Polarization measurements of hard X-rays from solar flares can provide a direct handle on the extent to which the accelerated electrons are beamed, which, in turn, has important implications for particle acceleration models. Past efforts to…

Astrophysics · Physics 2009-11-07 M. L. McConnell , J. M. Ryan , D. M. Smith , R. P. Lin , A. G. Emslie

The ultraviolet (UV) emission of stellar flares may have a pivotal role in the habitability of rocky exoplanets around low-mass stars. Previous studies have used white-light observations to calibrate empirical models which describe the…

Solar and Stellar Astrophysics · Physics 2022-11-09 James A. G. Jackman , Evgenya Shkolnik , Chase Million , Scott Fleming , Tyler Richey-Yowell , Parke Loyd

Sagittarius A*, the supermassive compact object at the center of the Galaxy, exhibits outbursts in the near infrared and X-ray domains. These flares are likely due to energetic events very close to the central object, on a scale of a few…

Astrophysics · Physics 2011-02-11 N. Hamaus , T. Paumard , T. Müller , S. Gillessen , F. Eisenhauer , S. Trippe , R. Genzel

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…

Sun-as-a-star spectroscopic characteristics of solar flares can be used as a benchmark for the detection and analyses of stellar flares. Here, we study the Sun-as-a-star properties of an X1.0 solar flare using high-resolution spectroscopic…

Solar and Stellar Astrophysics · Physics 2024-03-15 Y. L. Ma , Q. H. Lao , X. Cheng , B. T. Wang , Z. H. Zhao , S. H. Rao , C. Li , M. D. Ding

Solar flares are regularly observed in extreme ultraviolet (EUV), soft X-rays (SXR), and hard X-rays (HXR). However, those in near and mid-UV are sparse. The Solar Ultraviolet Imaging Telescope (SUIT) onboard the Aditya-L1, launched on 2nd…

Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot…

Solar and Stellar Astrophysics · Physics 2014-02-26 R. O. Parke Loyd , Kevin France

We present the first results from the "Low Energy Detector" payload of the "Solar X-ray Spectrometer (SOXS)" mission, which was launched onboard the GSAT-2 Indian spacecraft on 08 May 2003 by the GSLV-D2 rocket to study solar flares. The…

The Gaia-ESO Survey (GES) is a large public spectroscopic survey which acquired spectra for more than 100000 stars across all major components of the Milky Way. In addition to atmospheric parameters and stellar abundances that have been…

Power-law frequency distributions of the peak flux of solar flare X-ray emission have been studied extensively and attributed to a system of self-organized criticality (SOC). In this paper, we first show that, so long as the shape of the…

Solar and Stellar Astrophysics · Physics 2016-10-12 You-ping Li , Li Feng , Ping Zhang , Siming Liu , Weiqun Gan

Context: Solar flares release a large fraction of their energy into non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays are observed from the corona and chromosphere. Aims: We aim to characterize the acceleration…

Astrophysics · Physics 2009-11-11 Marina Battaglia , Arnold O. Benz

We report about the multi-frequency (1-30 GHz) daily monitoring of the radio flux variability of the three microquasars: SS433, GRS1915+105 and Cyg X-3 during the period from September 2005 to May 2006. 1. We detected clear correlation of…

Astrophysics · Physics 2007-05-23 S. A. Trushkin , N. N. Bursov , T. Kotani , N. A. Nizhelskij , M. Namiki , M. Tsuboi , P. A. Voitsik

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