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We introduce a novel method for discerning optical telescope images of stars from those of galaxies using Gaussian processes (GPs). Although applications of GPs often struggle in high-dimensional data modalities such as optical image…

Instrumentation and Methods for Astrophysics · Physics 2022-03-14 Amanda L. Muyskens , Imène R. Goumiri , Benjamin W. Priest , Michael D. Schneider , Robert E. Armstrong , Jason M. Bernstein , Ryan Dana

In high-resolution solar physics, the volume and complexity of photometric, spectroscopic, and polarimetric ground-based data significantly increased in the last decade reaching data acquisition rates of terabytes per hour. This is driven…

Instrumentation and Methods for Astrophysics · Physics 2018-05-23 C. Denker , C. Kuckein , M. Verma , S. J. González Manrique , A. Diercke , H. Enke , J. Klar , H. Balthasar , R. E. Louis , E. Dineva

We obtain contemporaneous observations of the surface and corona of AB Dor using ground-based circularly polarised spectra from the Anglo-Australian Telescope and X-ray data from the Chandra satellite. The ground-based data are used to…

X-ray and EUV observations are an important diagnostic of various plasma parameters of the solar atmosphere during solar flares. Soft X-ray and EUV observations often show coronal sources near the top of flaring loops, while hard X-ray…

Solar and Stellar Astrophysics · Physics 2015-06-11 Marina Battaglia , Eduard P. Kontar

Solar corona is much hotter than lower layers of the solar atmosphere-photosphere and chromosphere. The coronal temperature is up to 1MK in quiet sun areas, while up to several MK in active regions, which implies a key role of magnetic…

Solar and Stellar Astrophysics · Physics 2025-06-24 Gregory D. Fleishman , Alexey A. Kuznetsov , Gelu M. Nita

Gaussian processes are popular and flexible models for spatial, temporal, and functional data, but they are computationally infeasible for large datasets. We discuss Gaussian-process approximations that use basis functions at multiple…

Methodology · Statistics 2020-12-22 Matthias Katzfuss , Wenlong Gong

In order to support the creation of reliable machine learning models for anomaly detection, this project focuses on preprocessing, enhancing, and organizing a medical imaging dataset. There are two classifications in the dataset: normal and…

Image and Video Processing · Electrical Eng. & Systems 2024-11-20 Dharanidharan S , Suhitha Renuka S , Ajishi Singh , Sheena Christabel Pravin

Complex computer codes are often too time expensive to be directly used to perform uncertainty propagation studies, global sensitivity analysis or to solve optimization problems. A well known and widely used method to circumvent this…

Applications · Statistics 2008-04-06 Amandine Marrel , Bertrand Iooss , Francois Van Dorpe , Elena Volkova

Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power…

Solar and Stellar Astrophysics · Physics 2017-11-29 Samuel J. Van Kooten , Steven R. Cranmer

Coronae exist in most astrophysical objects: stars, accretion disks, and individual galaxies and clusters of galaxies. Coronae in these varied systems have some common properties: 1) hydrostatic equilibrium in background gravity is a good…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-10 Prateek Sharma

To explain the high temperature of the corona, much attention has been paid to the distribution of energy in dissipation events. Indeed, if the event energy distribution is steep enough, the smallest, unobservable events could be the…

Solar and Stellar Astrophysics · Physics 2016-07-06 Vincent Joulin , Éric Buchlin , Jacques Solomon , Chloé Guennou

Mismodeling the uncertain, diffuse emission of Galactic origin can seriously bias the characterization of astrophysical gamma-ray data, particularly in the region of the Inner Milky Way where such emission can make up over 80% of the photon…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Siddharth Mishra-Sharma , Kyle Cranmer

Small-scale propagating disturbances (PD) are ubiquitous in the solar corona. Time-Normalised Optical Flow (TNOF) is a method developed for mapping PD velocity fields in time series of Extreme-Ultraviolet (EUV) images. We show PD velocity…

Solar and Stellar Astrophysics · Physics 2026-02-04 Nina Stankovic , Huw Morgan , Marilena Mierla , Nancy Narang , Luciano Rodriguez , David Berghmans

We propose and test a wavelet transform modulus maxima method for the au- tomated detection and extraction of coronal loops in extreme ultraviolet images of the solar corona. This method decomposes an image into a number of size scales and…

Solar and Stellar Astrophysics · Physics 2010-02-17 R. T. James McAteer , Pierre Kestener , Alain Arneodo , Andre Khalil

Stellar coronae, defined by the ensemble of magnetic field structures above stellar photospheres and chromospheres together with their thermal or non-thermal plasma content, play an important role in our understanding of stellar magnetic…

Astrophysics · Physics 2007-05-23 M. Guedel

Diluted arrays of many optical apertures will be able to provide h igh-resolution snapshot images if the beams are combined according to the densified-pupil scheme. We show that the same principle can also provide coronagraphic images, for…

Astrophysics · Physics 2009-10-31 A. Boccaletti , P. Riaud , C. Moutou , A. Labeyrie

For the first time, we report a large-scale wave that was observed simultaneously in the photosphere, chromosphere, transition region and low corona layers of the solar atmosphere. Using the high temporal and high spatial resolution…

Solar and Stellar Astrophysics · Physics 2015-06-05 Yuandeng Shen , Yu Liu

Context: In this paper we present a validation scheme to investigate the quality of coronal magnetic field models, which is based upon comparisons with observational data from multiple sources. Aims: Many of these coronal models may use a…

Solar and Stellar Astrophysics · Physics 2022-02-09 A. Wagner , E. Asvestari , M. Temmer , S. G. Heinemann , J. Pomoell

The content of hot material in the corona is not constant. Soft X-ray and high-temperature EUV line observations show that new material, apparently heated and evaporated from the chromosphere, is frequently injected into the corona both in…

Astrophysics · Physics 2016-08-30 Arnold O. Benz , Paolo C. Grigis

A joint campaign of several space-borne and ground-based observatories, such as the GREGOR solar telescope, the Extreme-ultraviolet Imaging Spectrometer (EIS), and the Interface Region Imaging Spectrograph (Hinode Observing Plan 381, 11-22…