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We compare four different methods of calculating uncertainty estimates in fitting parameterized models to RHESSI X-ray spectra, considering only statistical sources of error. Three of the four methods are based on estimating the scale-size…

Solar and Stellar Astrophysics · Physics 2015-06-15 Jack Ireland , Anne K. Tolbert , Richard A. Schwartz , Gordon D. Holman , Brian R. Dennis

We develop a new and powerful method to analyze time series to rigorously detect flares in the presence of an irregularly oscillatory baseline, and apply it to stellar light curves observed with TESS. First, we remove the underlying…

Solar and Stellar Astrophysics · Physics 2025-12-23 Qiyuan Wang , Giovanni Motta , Genaro Sucarrat , Vinay L. Kashyap

Aims: To formulate, implement, and validate a user-independent release of CLEAN for Fourier-based image reconstruction of hard X-rays flaring sources. Methods: CLEAN is an iterative deconvolution method for radio and hard X-ray solar…

Instrumentation and Methods for Astrophysics · Physics 2023-07-20 Emma Perracchione , Fabiana Camattari , Anna Volpara , Paolo Massa , Anna Maria Massone , Michele Piana

The hard X-ray (HXR) emission in solar flares comes almost exclusively from a very small part of the flaring region, the footpoints of magnetic loops. Using RHESSI observations of solar flare footpoints, we determine the radial positions…

Solar and Stellar Astrophysics · Physics 2015-05-27 Marina Battaglia , Eduard P. Kontar

Time-correlated variations in the pulse profiles of radio pulsars provide insights into changes in their magnetospheres. For a small number of pulsars (~20), these variations have been shown to correlate with spin-down rate. Many of these…

High Energy Astrophysical Phenomena · Physics 2025-05-30 Michael J. Keith , Renée Spiewak , Andrew G. Lyne , Patrick Weltevrede , Danai Antonopoulou , Ben Stappers

Adverse space weather effects can often be traced to solar flares, prediction of which has drawn significant research interests. The Helioseismic and Magnetic Imager (HMI) produces full-disk vector magnetograms with continuous high cadence,…

Solar and Stellar Astrophysics · Physics 2017-07-26 Chang Liu , Na Deng , Jason T. L. Wang , Haimin Wang

We report a NuSTAR observation of a solar microflare, SOL2015-09-01T04. Although it was too faint to be observed by the GOES X-ray Sensor, we estimate the event to be an A0.1 class flare in brightness. This microflare, with only 5 counts…

In recent work done by Sun et. al., the color variation of quasars, namely the bluer-when-brighter trend, was found to be timescale-dependent using SDSS $g/r$ band light curves in the Stripe 82. Such timescale dependence, i.e., bluer…

Astrophysics of Galaxies · Physics 2016-12-07 Fei-Fan Zhu , Jun-Xian Wang , Zhen-Yi Cai , Yu-Han Sun

We present the first systematic investigation of the morphological and timing properties of flares in GRBs observed by Swift/XRT. We consider a large sample drawn from all GRBs detected by Swift, INTEGRAL and HETE-2 prior to 2006 Jan 31,…

A high-resolution X-ray spectroscopic observation was made of the RS CVn-type binary star HR 1099 using the Resolve instrument onboard XRISM for its calibration purposes. During the $\sim$400 ks telescope time covering 1.5 binary orbit, a…

The detection of terrestrial planets by radial velocity and photometry is hindered by the presence of stellar signals. Those are often modeled as stationary Gaussian processes, whose kernels are based on qualitative considerations, which do…

Solar and Stellar Astrophysics · Physics 2025-04-23 Nathan C. Hara , Jean-Baptiste Delisle

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 have analyzed 5.5 years of timing observations of 7 'slowly' rotating radio pulsars, made with the Westerbork Synthesis Radio Telescope. We present improved timing solutions and 30, mostly small, new glitches. Particularly interesting…

Astrophysics · Physics 2009-11-11 G. H. Janssen , B. W. Stappers

We report on the results of our simultaneous observations of three large stellar flares with soft X-rays (SXRs) and an H$\mathrm{\alpha}$ emission line from two binary systems of RS CVn type. The energies released in the X-ray and…

High Energy Astrophysical Phenomena · Physics 2023-07-06 Hiroki Kawai , Yohko Tsuboi , Wataru B. Iwakiri , Yoshitomo Maeda , Satoru Katsuda , Ryo Sasaki , Junya Kohara , MAXI TEAM

Monitoring of Sagittarius A* from X-ray to radio wavelengths has revealed structured variability --- including X-ray flares --- but it is challenging to establish correlations between them. Most studies have focused on variability in the…

It is well known among the scientific community that solar flare activity often begins well before the main impulsive energy release. Our aim is to investigate the earliest phase of four distinct flares observed by Solar Orbiter/STIX and…

We present temporal and spectral characteristics of X-ray flares observed from six late-type G-K active dwarfs (V368 Cep, XI Boo, IM Vir, V471 Tau, CC Eri and EP Eri) using data from observations with the XMM-Newton observatory. All the…

Astrophysics · Physics 2009-11-13 J. C. Pandey , K. P. Singh

Context. Solar-like oscillations exhibit a regular pattern of frequencies. This pattern is dominated by the small and large frequency separations between modes. The accurate determination of these parameters is of great interest, because…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 René Kiefer , Ariane Schad , Wiebke Herzberg , Markus Roth

Modern-day civil, mechanical, and aeronautical structures are transitioning towards a continuous, online, and automated maintenance paradigm in order to ensure increased safety and reliability. The field of structural health monitoring…

Signal Processing · Electrical Eng. & Systems 2022-01-14 Shabbir Ahmed , Fotis Kopsaftopoulos

We have constructed timing solutions for 81 gamma-ray pulsars covering more than five years of Fermi data. The sample includes 37 radio-quiet or radio-faint pulsars which cannot be timed with other telescopes. These timing solutions and the…

High Energy Astrophysical Phenomena · Physics 2015-12-02 Matthew Kerr , Paul Ray , Simon Johnston , Ryan Shannon , Fernando Camilo
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