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Related papers: New Observations of the Solar 0.5-5 keV Soft X-ray…

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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

New Swift monitoring observations of the variable, radio-quiet quasar, PDS 456, are presented. A bright X-ray flare was captured in September 2018, the flux increasing by a factor of 4 and with a doubling time-scale of 2 days. From the…

High Energy Astrophysical Phenomena · Physics 2020-11-11 James Reeves , Valentina Braito , Delphine Porquet , Andrew Lobban , Gabriele Matzeu , Emanuele Nardini

Measuring the relative amount of high-temperature, low-emission-measure plasma is considered to be a smoking gun observation to constrain the frequency of plasma heating in coronal structures. Often, narrowband, extreme ultraviolet images,…

Solar and Stellar Astrophysics · Physics 2024-01-24 P. S. Athiray , Amy R. Winebarger

The infrared solar spectrum contains a wealth of physical data about the Sun and is being explored using modern detectors and technology with new ground-based solar telescopes. One such instrument will be the ground-based Cryogenic Near-IR…

Solar and Stellar Astrophysics · Physics 2022-06-22 Aatiya Ali , Alin Paraschiv , Kevin Reardon , Philip Judge

A soft X-ray excess above the 2-10 keV power law extrapolation is generally observed in AGN X-ray spectra. Presently there are two competitive models to explain it: blurred ionized reflection and warm Comptonisation. In the latter case,…

High Energy Astrophysical Phenomena · Physics 2020-02-12 P. -O. Petrucci , D. Gronkiewicz , A. Rozanska , R. Belmont , S. Bianchi , B. Czerny , G. Matt , J. Malzac , R. Middei , A. De Rosa , F. Ursini , M. Cappi

In the X-ray spectra of AGNs, a noticeable excess of soft X-rays is typically detected beyond the extrapolation of the power-law trend observed between 2-10 keV. In the scenario of warm Comptonization, observations propose a warm corona…

High Energy Astrophysical Phenomena · Physics 2024-09-18 B. Palit , A. Rozanska , P. O. Petrucci , D. Gronkiewicz , S. Barnier , S. Bianchi , D. R. Ballantyne , V. E. Gianolli , R. Middei , R. Belmont , F. Ursini

We present the X-ray analysis of coronal properties in a statistically representative sample of 23 mostly radio-quiet AGN from the SUBWAYS campaign (SUpermassive Black holes Winds in XrAYs), focusing on quasars at redshifts $0.1 < z < 0.4 $…

Spectroscopic observations in X-ray wavelengths provide excellent diagnostics of the temperature distribution in solar flare plasma. The Solar X-ray Monitor (XSM) onboard the Chandrayaan-2 mission provides broad-band disk integrated soft…

Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations…

Solar and Stellar Astrophysics · Physics 2009-07-22 Harry P. Warren , David H. Brooks

The current status of understanding of the X-ray emission from Seyfert galaxies involves Comptonization of soft photons by hot subrelativistic electrons. After briefly reviewing the early theoretical basis for the presence of hot optically…

Astrophysics · Physics 2007-05-23 Laura Maraschi , Francesco Haardt

Context: Solar flare hard X-rays (HXRs) are thought to be produced by nonthermal coronal electrons stopping in the chromosphere, or remaining trapped in the corona. The collisional thick target model (CTTM) predicts that sources produced by…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. O'Flannagain , P. Gallagher , J. Brown , R. Milligan , G. Holman

Context: Solar flares release a large fraction of their energy into non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays are observed from the corona and chromosphere. Aims: We aim to characterize the acceleration…

Astrophysics · Physics 2009-11-11 Marina Battaglia , Arnold O. Benz

The large uncertainties associated with measuring the amount of high temperature emission in solar active regions represents a significant impediment to making progress on the coronal heating problem. Most current observations at…

Solar and Stellar Astrophysics · Physics 2012-07-20 Luca Teriaca , Harry Warren , Werner Curdt

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,…

Solar five-minute oscillations have been detected in the power spectra of two six-day time intervals from soft X-ray measurements of the Sun observed as a star using the Extreme Ultraviolet Spectrophotometer (ESP) onboard the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2015-06-12 Leonid Didkovsky , Alexander Kosovichev , Darrell Judge , Seth Wieman , Tom Woods

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

Recent simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high temperature emission observed at soft X-ray wavelengths using static heating models.…

Astrophysics · Physics 2011-02-11 Harry P. Warren , Amy R. Winebarger

The investigation of small-scale energy release in the Sun's atmosphere is important in understanding how the corona is heated. Previous work has been able to study small EUV and SXR brightenings outside of active regions (i.e. the quiet…

The aim of this paper is to study the latitudinal variation in the solar rotation in soft X-ray corona. The time series bins are formed on different latitude regions of the solar full disk (SFD) images that extend from 80 degree South to 80…

Solar and Stellar Astrophysics · Physics 2015-05-18 Satish Chandra , Hari Om Vats , K. N. Iyer

Time profiles of solar soft X-ray microflares and structure soft X-ray solar corona thermal background are studied on RHESSI data. The observations of 2003 year are analyzed. Decrease fluxe of solar soft X-ray microflares and thermal…

Solar and Stellar Astrophysics · Physics 2011-06-16 I. K. Mirzoeva