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The Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) was designed to study diffuse emission from hot gas in the local interstellar cavity in the wavelength range 90 - 265 A. Between launch in January 2003 and early 2004, the instrument…

Astrophysics · Physics 2009-11-10 M. Hurwitz , T. P. Sasseen , M. M. Sirk

The EUV late phase is the second increase of the irradiance of the warm coronal lines during solar flares, and has a crucial impact on the Earth's ionosphere. In this paper, we report on the extremely energetic EUV late phase of a pair of…

Solar and Stellar Astrophysics · Physics 2025-12-10 Ya Wang , Sargam M. Mulay , Lyndsay Fletcher

Enhanced continuum brightness is observed in many flares (''white light flares''), yet it is still unclear which processes contribute to the emission. To understand the transport of energy needed to account for this emission, we must first…

Solar and Stellar Astrophysics · Physics 2016-01-27 Lucia Kleint , Petr Heinzel , Phil Judge , Säm Krucker

We performed coordinated observations of AR 12205, which produced a C-class flare on 2014 November 11, with the Interface Region Imaging Spectrograph (IRIS) and the Domeless Solar Telescope (DST) at Hida Observatory. Using spectral data in…

The gravitational redshift measured by Cottam, Paerels and Mendez for the neutron star (NS) in the low-mass X-ray binary EXO 0748-676 depends on the identification of an absorption line during a type I burst as the H$\alpha$ line from…

Astrophysics · Physics 2009-11-07 L. Bildsten , P. Chang , F. Paerels

Quiet Sun and active region spectra from the Hinode/EIS instrument are presented, and the strongest lines from different temperature regions discussed. A list of emission lines recommended to be included in EIS observation studies is…

The extreme ultraviolet (EUV) and X-ray radiation emitted during solar flares has been shown to significantly increase the electron density of the Earth's ionosphere. During flares, quasi-periodic pulsations (QPPs) in X-ray flux originating…

Solar and Stellar Astrophysics · Physics 2025-04-11 Aisling N. O'Hare , Susanna Bekker , Laura A. Hayes , Ryan O. Milligan

Chromospheric evaporation (CE) and coronal rain (CR) represent two crucial phenomena encompassing the circulation of mass and energy during solar flares. While CE marks the start of the hot inflow into the flaring loop, CR marks the end,…

Solar and Stellar Astrophysics · Physics 2024-06-05 Seray Sahin , Patrick Antolin

In a solar flare, a large fraction of the magnetic energy released is converted rapidly to the kinetic energy of non-thermal particles and bulk plasma motion. This will likely result in non-equilibrium particle distributions and turbulent…

Solar and Stellar Astrophysics · Physics 2017-02-15 Natasha L. S. Jeffrey , Lyndsay Fletcher , Nicolas Labrosse

In order to better understand the nature of active region outflows, the electron density was measured by using a density-sensitive line pair Fe xiv 264.78A/274.20A.Since coronal line profiles of the outflow region are composed of a major…

Solar and Stellar Astrophysics · Physics 2015-06-03 Naomasa Kitagawa , Takaaki Yokoyama

We have imaged the extremely high-velocity outflowing gas in CO (2-1) and (3-2) associated with the shell-like ultracompact HII region G5.89-0.39 at a resolution of ~3" (corresponding to ~4000 AU) with the Submillimeter Array. The…

Solar and Stellar Astrophysics · Physics 2015-06-03 Yu-Nung Su , Sheng-Yuan Liu , Huei-Ru Chen , Ya-Wen Tang

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed…

Solar and Stellar Astrophysics · Physics 2015-11-04 X. Fang , D. Yuan , T. Van Doorsselaere , R. Keppens , C. Xia

Theoretical emission-line ratios involving Fe XI transitions in the 257-407 A wavelength range are derived using fully relativistic calculations of radiative rates and electron impact excitation cross sections. These are subsequently…

Solar and Stellar Astrophysics · Physics 2015-05-18 F. P. Keenan , R. O. Milligan , D. B. Jess , K. M. Aggarwal , M. Mathioudakis , R. J. Thomas , J. W. Brosius , J. M. Davila

Investigate particle acceleration and heating in a solar microflare. In a microflare with non-thermal emission to remarkably high energies ($>50$ keV), we investigate the hard X-rays with RHESSI imaging and spectroscopy and the resulting…

Astrophysics · Physics 2010-09-17 I. G. Hannah , S. Krucker , H. S. Hudson , S. Christe , R. P. Lin

Coronal mass ejection spray plasma associated with the M1.5-class flare of 16 February 2011 is found to exhibit a Doppler blue-shift of 850 km/s - the largest value yet reported from ultraviolet (UV) or extreme ultraviolet (EUV)…

Solar and Stellar Astrophysics · Physics 2023-02-08 Peter R. Young

Using joint observations from Hinode/EIS and the Atmospheric Imaging Array (AIA) on the Solar Dynamics Observatory we explore the asymmetry of coronal EUV line profiles. We find that asymmetries exist in all of the spectral lines studied,…

Solar and Stellar Astrophysics · Physics 2012-01-26 Marybeth Sechler , Scott W. McIntosh , Hui Tian , Bart De Pontieu

The intensity of the \oiv~2s$^{2}$ 2p $^{2}$P-2s2p$^{2}$ $^{4}$P and \siv~3 s$^{2}$ 3p $^{2}$P- 3s 3p$^{2}$ $^{4}$ P intercombination lines around 1400~\AA~observed with the \textit{Interface Region Imaging Spectrograph} (IRIS) provide a…

Solar and Stellar Astrophysics · Physics 2016-10-19 V. Polito , G. Del Zanna , J. Dudík , H. E. Mason , A. Giunta , K. K. Reeves

In this research, we investigate Explosive Events (EEs) in the off-limb solar atmosphere, with simultaneous observations from the Si IV, Mg II k, and slit-jaw images (SJI) of the Interface Region Imaging Spectrograph (IRIS), on 17 August…

Solar and Stellar Astrophysics · Physics 2022-07-06 E. Tavabi , S. Zeighami , M. Heydari

We used spectropolarimetric observations of a sunspot in active region NOAA 11809 in the Ca ii line at 854.2 nm taken with the SpectroPolarimeter for Optical and Infrared Regions (SPINOR) at the Dunn Solar Telescope to infer thermodynamic…

Solar and Stellar Astrophysics · Physics 2018-04-23 Debi Prasad Choudhary , Christian Beck

A model has been proposed for estimation of plasma parameters of explosive electron emission pulses in vacuum arc discharge. It based on transition through the critical state during the explosion and allow to predict the cathode spot plasma…

Plasma Physics · Physics 2020-10-26 M. M. Tsventoukh