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Related papers: Determination of coronal temperatures from electro…

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Statistical uncertainties in determining the temperatures of hot (0.5 keV to 10 keV) coronal plasmas are investigated. The statistical precision of various spectral temperature diagnostics is established by analyzing synthetic ASCA…

Astrophysics · Physics 2009-10-22 Douglas A. Swartz , S. L. O'Dell , M. E. Sulkanen , A. F. Tennant

X-Ray and Ultraviolet (UV) observations of the outer solar atmosphere have been used for many decades to measure the fundamental parameters of the solar plasma. This review focuses on the optically thin emission from the solar atmosphere,…

Solar and Stellar Astrophysics · Physics 2018-09-06 Giulio Del Zanna , Helen E. Mason

The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…

Solar and Stellar Astrophysics · Physics 2023-05-17 Yingjie Zhu , Judit Szente , Enrico Landi

The quiet solar corona emits meter-wave thermal bremsstrahlung. Coronal radio emission can only propagate above that radius, $R_\omega$, where the local plasma frequency eqals the observing frequency. The radio interferometer LOw Frequency…

Solar and Stellar Astrophysics · Physics 2018-06-13 C. Vocks , G. Mann , F. Breitling , M. M. Bisi , B. Dabrowski , R. Fallows , P. T. Gallagher , A. Krankowski , J. Magdalenic , C. Marque , D. Morosan , H. Rucker

In the present work we use a deep-exposure spectrum taken by the SUMER spectrometer in a polar coronal hole in 1996 to measure the ion temperatures of a large number of ions at many different heights above the limb between 0.03 and 0.17…

Astrophysics · Physics 2011-02-11 Enrico Landi , Steven R. Cranmer

An iterative method is presented for reconstructing the height-temperature profile of the solar atmosphere above a sunspot using multi-frequency spectro-polarimetric microwave observations. It is assumed that the emission is formed…

Solar and Stellar Astrophysics · Physics 2026-03-09 T. I. Kaltman , A. G. Stupishin , G. A. Makoev

We propose a novel method to constrain the Milky Way (MW) mass $M_{\rm vir}$ with its corona temperature observations. For a given corona density profile, one can derive its temperature distribution assuming a generalized equilibrium model…

Astrophysics of Galaxies · Physics 2020-12-02 Fulai Guo , Ruiyu Zhang , Xiang-Er Fang

Aims. We study the X-ray emission of low-mass main-sequence stars to derive a reliable general scaling law between coronal temperature and the level of X-ray activity. Methods. We collect ROSAT measurements of hardness ratios and X-ray…

Solar and Stellar Astrophysics · Physics 2015-05-21 Colin P. Johnstone , Manuel Güdel

The Sun's corona is millions of degrees hotter than its 5,000 K photosphere. This heating enigma is typically addressed by invoking the deposition at coronal heights of non-thermal energy generated by the interplay between convection and…

Solar and Stellar Astrophysics · Physics 2009-08-11 Bart De Pontieu , Scott W. McIntosh , Viggo H. Hansteen , Carolus J. Schrijver

One of the most important objectives of solar physics is the physical understanding of the solar atmosphere, the structure of which is also described in terms of the density (N) and temperature (T) distributions of the atmospheric matter.…

Daily differential emission measure (DEM) distributions of the solar corona are derived from spectra obtained by the Extreme-ultraviolet Variability Experiment (EVE) over a 4-year period starting in 2010 near solar minimum and continuing…

Solar and Stellar Astrophysics · Physics 2020-09-16 Samuel J. Schonfeld , Stephen M. White , Rachel A. Hock-Mysliwiec , R. T. James McAteer

The reconstruction of the differential emission measure (DEM) from observations of spectral line intensities provides information on the temperature distribution of the emission measure in the region observed. The inversion process is known…

Solar and Stellar Astrophysics · Physics 2022-05-18 Kenneth P. Dere

We present a Differential Emission Measure (DEM) analysis of the quiet solar corona on disk using data obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on {\it Hinode}. We show that the expected quiet Sun DEM distribution can…

Solar and Stellar Astrophysics · Physics 2009-11-09 David H. Brooks , Harry P. Warren , David R. Williams , Tetsuya Watanabe

Using the APEX-12m telescope, continuum maps at 350~$\mu$m of eight gas-dust clouds from the southern hemisphere are obtained. Clouds are associated with the regions of massive star and star cluster formation and have dense cores. Core…

Astrophysics of Galaxies · Physics 2023-01-12 L. E. Pirogov

We identify coronal holes using a histogram-based intensity thresholding technique and compare their properties to fast solar wind streams at three different points in the heliosphere. The thresholding technique was tested on EUV and X-ray…

Solar and Stellar Astrophysics · Physics 2009-05-13 Larisza D. Krista , Peter T. Gallagher

Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from…

Solar and Stellar Astrophysics · Physics 2015-12-15 Judith de Patoul , Claire Foullon , Pete Riley

Electrons densities in different locations of our galaxy are obtained in pulsar astronomy by dividing the dispersion measure (DM) by the distance of the pulsar to Earth. The properties of the interstellar plasma are related to its heating.…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Y. Ben-Aryeh

The solar atmosphere shows anomalous variation in temperature, starting from the 5500 K photosphere to the million-degree Kelvin corona. The corona itself expands into the interstellar medium as the free streaming solar wind, which…

Solar and Stellar Astrophysics · Physics 2023-04-05 Vishal Upendran

In this paper, the ability of the Hinode/EIS instrument to detect radiative signatures of coronal heating is investigated. Recent observational studies of AR cores suggest that both the low and high frequency heating mechanisms are…

Solar and Stellar Astrophysics · Physics 2015-06-16 Chloé Guennou , Frédéric Auchère , James A. Klimchuk , Karine Bocchialini , Susanna Parenti