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The Bent Crystal Spectrometer (BCS) onboard the NASA Solar Maximum Mission was part of the X-ray Polychromator, which observed numerous flares and bright active regions from February to November 1980, when operation was suspended as a…

Instrumentation and Methods for Astrophysics · Physics 2017-04-12 C. G. Rapley , J. Sylwester , K. J. H. Phillips

We present new calculations of atomic data needed to model autoionizing states of Fe XVI. We compare the state energies, radiative and excitation data with a sample of results from previous literature. We find a large scatter of results,…

Solar and Stellar Astrophysics · Physics 2024-05-03 G. Del Zanna , N. R. Badnell , P. J. Storey

Context: Flare kernels brighten simultaneously in all SDO/AIA channels making it difficult to determine their temperature structure. IRIS is able to spectrally resolve Fe xxi emission from cold chromospheric brightenings, so can be used to…

Solar and Stellar Astrophysics · Physics 2016-02-17 D. Li , D. E. Innes , Z. J. Ning

In this work we investigate the thermal structure of an off-limb active region in various non-flaring areas, as it provides key information on the way these structures are heated. In particular, we concentrate in the very hot component (>3…

Solar and Stellar Astrophysics · Physics 2017-09-06 Susanna Parenti , Giulio del Zanna , Antonino Petralia , Fabio Reale , Luca Teriaca , Paola Testa , Helen E. Mason

We performed extensive tests of the accuracy of atmospheric parameter determination for FGK stars based on the spectrum fitting procedure Spectroscopy Made Easy (SME). Our stellar sample consists of 13 objects, including the Sun, in the…

Solar and Stellar Astrophysics · Physics 2016-01-27 T. Ryabchikova , N. Piskunov , Yu. Pakhomov , V. Tsymbal , A. Titarenko , T. Sitnova , S. Alexeeva , L. Fossati , L. Mashonkina

The Galactic center region was observed with the XRISM X-ray observatory during the performance verification phase in 2024 and a point-like X-ray source was detected with the X-ray imager Xtend at a position of (RA, Dec)=(17h46m10.8s,…

We report the detection of emission from a non-thermal electron distribution in a small solar microflare (GOES class A5.7) observed by the Nuclear Spectroscopic Telescope Array (NuSTAR), with supporting observation by the Reuven Ramaty High…

We investigate the type III radio bursts and X-ray signatures of accelerated electrons in a well observed solar flare in order to find the spatial properties of the acceleration region. Combining simultaneous RHESSI hard X-ray flare data…

Solar and Stellar Astrophysics · Physics 2015-05-27 H. A. S. Reid , N. Vilmer , E. P. Kontar

By combining high-sensitivity LOFAR 150MHz, uGMRT 400MHz and 1,250MHz, GMRT 610MHz, and VLA 5GHz data in the ELAIS-N1 field, we study the radio spectral properties of radio-detected star-forming galaxies (SFGs) at observer-frame frequencies…

The Geostationary Operational Environmental Satellite (GOES) solar soft X-ray (SXR) irradiance in the 1-8{\AA} wavelength range is a long-standing measure of solar activity, used to define the classification of flare strengths. As a result,…

The observation of the supernova remnant N132D by the scientific instruments on board the XMM-Newton satellite is presented. The X-rays from N132D are dispersed into a detailed line-rich spectrum using the Reflection Grating Spectrometers.…

The X-shooter Spectral Library (XSL) is a large empirical stellar library used as a benchmark for the development of stellar population models. The inclusion of $\alpha$-elements abundances is crucial to disentangling the chemical evolution…

Astrophysics of Galaxies · Physics 2023-04-19 Pablo Santos-Peral , Patricia Sánchez-Blázquez , Alexandre Vazdekis , Pedro A. Palicio

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

In the era of vast spectroscopic surveys focusing on Galactic stellar populations, astronomers want to exploit the large quantity and good quality of data to derive their atmospheric parameters without losing precision from automatic…

Solar and Stellar Astrophysics · Physics 2017-12-13 M. Tsantaki , D. T. Andreasen , G. D. C. Teixeira , S. G. Sousa , N. C. Santos , E. Delgado-Mena , G. Bruzual

We present the analysis of emission lines in high-resolution optical spectra of the planet-host star Proxima Centauri (Proxima) classified as a M5.5V\@. We carry out the detailed analysis of observed spectra to get a better understanding of…

Solar and Stellar Astrophysics · Physics 2017-10-11 Ya. V. Pavlenko , A. Suarez Mascareno , R. Rebolo , N. Lodieu , V. J. S. Bejar , J. I. Gonzalez Hernandez

We use a deep XMM-Newton Reflection Grating Spectrometer observation to examine the X-ray emission from the core of the Centaurus cluster of galaxies. We clearly detect Fe-XVII emission at four separate wavelengths, indicating the presence…

Astrophysics · Physics 2009-11-13 J. S. Sanders , A. C. Fabian , S. W. Allen , R. G. Morris , J. Graham , R. M. Johnstone

We present the result of comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we…

Solar and Stellar Astrophysics · Physics 2017-08-30 A. S. Kirichenko , S. A. Bogachev

We present a method for the determination of [alpha/Fe] ratios from low-resolution (R = 2000) SDSS/SEGUE stellar spectra. By means of a star-by-star comparison with degraded spectra from the ELODIE spectral library and with a set of…

In this work we study the correlation between the soft (1.6--12.4 keV, mostly thermal) and the hard (20--40 and 60--80 keV, mostly non-thermal) X-ray emission in solar flares up to the most energetic events, spanning about 4 orders of…

Astrophysics · Physics 2009-11-13 C. Isola , F. Favata , G. Micela , H. S. Hudson

We report multi-wavelength monitoring observations of an M-dwarf flare star AD Leonis with Seimei Telescope (6150--7930 {\AA}), SCAT (Spectroscopic Chuo-university Astronomical Telescope; 3700--7500 {\AA}), NICER (Neutron Star Interior…

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