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The focus of this investigation is to quantify the conversion of magnetic to thermal energy initiated by a quiet Sun cancellation event and to explore the resulting dynamics from the interaction of the opposite polarity magnetic features.…

Solar and Stellar Astrophysics · Physics 2023-03-29 Anjali. J. Kaithakkal , J. M. Borrero , A. Pastor Yabar , J. de la Cruz Rodríguez

In this article, an active contours without edges (ACWE)-based algorithm has been proposed for the detection of solar filaments in H-alpha full-disk solar images. The overall algorithm consists of three main steps of image processing. These…

Computer Vision and Pattern Recognition · Computer Science 2024-12-31 Sanmoy Bandyopadhyay , Vaibhav Pant

Observations of astronomical objects in the far ultraviolet (FUV wavelengths span 900-1800{\AA}) from earth's orbit has been impeded due to bright Lyman-{\alpha} geocoronal emission. The Johns Hopkins Rocket Group is developing a hydrogen…

Instrumentation and Methods for Astrophysics · Physics 2021-09-07 Isu Ravi , Stephan R. McCandliss , Russell Pelton

The aim of this study is to demonstrate how the logarithmic millimeter continuum gradient observed using the Atacama Large Millimeter/submillimeter Array (ALMA) may be used to estimate optical thickness in the solar atmosphere. We discuss…

Solar and Stellar Astrophysics · Physics 2019-05-01 Andrew S. Rodger , Nicolas Labrosse , Sven Wedemeyer , Mikolaj Szydlarski , Paulo J. A. Simões , Lyndsay Fletcher

We explore the possibility of resolving an image of a damped Lyman alpha (DLA) system in absorption against an extended, diffuse background X-ray source. Typical columns of neutral hydrogen in DLAs are high enough to block out up to ~30% of…

Astrophysics · Physics 2009-11-10 Mark Dijkstra , Zoltan Haiman , Caleb Scharf

Full disc observations of the Sun in the H$\alpha$ line provide information about the solar chromosphere and in particular about the filaments, which are dark and elongated features that lie along magnetic field polarity inversion lines.…

Solar storms can have a major impact on the infrastructure of the earth. Some of the causing events are observable from ground in the H{\alpha} spectral line. In this paper we propose a new method for the simultaneous detection of flares…

Computer Vision and Pattern Recognition · Computer Science 2013-04-29 Gernot Riegler , Thomas Pock , Werner Pötzi , Astrid Veronig

The strong enhancement of the ultraviolet emission during solar flares is usually taken as an indication of plasma heating in the lower solar atmosphere caused by the deposition of the energy released during these events. Images taken with…

Solar and Stellar Astrophysics · Physics 2019-01-23 Paulo J. A. Simões , Hamish A. S. Reid , Ryan O. Milligan , Lyndsay Fletcher

The Alfv\'{e}n speed and plasma beta in photospheric bright points observed by the Broadband Filter Imager (BFI) of the Solar Optical Telescope (SOT) on board the \textit{Hinode} satellite, are estimated seismologically. The diagnostics is…

Kanzelh\"ohe Observatory (KSO) regularly performs high-cadence full-disk imaging of the solar chromosphere in the H$\alpha$ and CaIIK spectrallines as well as the solar photosphere in white-light. In the frame of ESA's Space Situational…

DEM analysis is a major diagnostic tool for stellar atmospheres. But both its derivation and its interpretation are notably difficult because of random and systematic errors, and the inverse nature of the problem. We use simulations with…

Solar and Stellar Astrophysics · Physics 2013-06-17 Chloé Guennou , Frédéric Auchère , Elie Soubrié , Karine Bocchialini , Susanna Parenti

We present the first detection of solar flare emission at middle-ultraviolet wavelengths around 2000 A by the channel 2 of the Large-Yield RAdiometer (LYRA) onboard the PROBA2 mission. The flare (SOL20170906) was also observed in the…

Ellerman bombs (EBs) and UV bursts are both small-scale solar activities that occur in active regions. They are now believed to form at different heights in the lower atmosphere. In this paper, we use one-dimensional radiative hydrodynamic…

Solar and Stellar Astrophysics · Physics 2021-11-09 Jie Hong , Ying Li , M. D. Ding , Qi Hao

We present an initial study of one of the first ALMA Band 3 observations of the Sun with the aim to characterise the diagnostic potential of brightness temperatures measured with ALMA on the Sun. The observation covers 48min at a cadence of…

The ALHAMBRA (Advance Large Homogeneous Area Medium Band Redshift Astronomical) survey has observed 8 different regions of the sky, including sections of the COSMOS, DEEP2, ELAIS, GOODS-N, SDSS and Groth fields using a new photometric…

We present the Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) selected from MUSE and HST observations of 17 lensing clusters. The sample consists of 603 continuum-faint (-23<M_UV<-14) lensed Lyman-alpha emitters (producing 959 images) with…

Large and magnetically complex sunspot groups are known to be associated with flares. To date, the Mount Wilson scheme has been used to classify sunspot groups based on their morphological and magnetic properties. The most flare prolific…

Solar and Stellar Astrophysics · Physics 2016-01-20 Sreejith Padinhatteeri , Paul A. Higgins , D. Shaun Bloomfield , Peter T. Gallagher

We have obtained deep, high spatial resolution images of the central region of Abell 1795 at Halpha and [NII] (6583A) with the Maryland Magellan Tunable Filter (MMTF), and in the far-ultraviolet (FUV) with the Advanced Camera for Surveys…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Michael McDonald , Sylvain Veilleux

The Lyman-alpha (Ly{\alpha};1216 {\AA}) line is the brightest emission line in the quiescent solar spectrum and radiates a significant fraction of the available nonthermal energy during flares. Despite its importance, there is a lack of…

Solar and Stellar Astrophysics · Physics 2025-04-25 Luke Majury , Ryan Milligan , Elizabeth Butler , Harry Greatorex , Maria Kazachenko

Coronal bright points (CBP) are ubiquitous small brightenings in the solar corona associated with small magnetic bipoles. We derive the solar differential rotation profile by tracing the motions of CBPs detected by the Atmospheric Imaging…

Solar and Stellar Astrophysics · Physics 2015-02-25 Davor Sudar , Ivica Skokić , Roman Brajša , Steven H. Saar
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