The solar coronal X-ray spectrum from 5.5 to 12 A

McKenzie, D. L.; Landecker, P. B.; Feldman, U.; Doschek, G. A.

doi:10.1086/162949

Cited by 52 publications

(45 citation statements)

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“…The results show a strong similarity in overall spectral shape between the two objects at photon energies above 1 keV. Although each observation was taken during separate solar flares, the peak structures above 1 keV agree with regular features seen in observed solar flare spectra (McKenzie et al 1985) and are common for average M-class solar flare activity (Dere et al 1997;Landi et al 2013).…”

Section: Comparison Of Ikeya-zhang To Jovian Disk As Evidence Of Scatsupporting

confidence: 72%

“…The CHIANTI atomic database, a theoretical emission line database specifically designed for astrophysical plasmas, is used to model the relative spectral intensities (spectral shape) of the X-ray spectrum from 0.3−3.0 keV (Dere et al 1997;Landi et al 2013). The modeled spectrum is compared to observational data from McKenzie et al (1985) taken from SOLEX-A, and both are in good agreement. Slight discrepancies present are likely a result of fluctuations of solar X-ray line intensities which naturally occur over time (Neupert 2006).…”

Section: Solar Intensitymentioning

confidence: 99%

“…Slight discrepancies present are likely a result of fluctuations of solar X-ray line intensities which naturally occur over time (Neupert 2006). The results from McKenzie et al (1985) and CHIANTI provide a reliable database from which we can extrapolate a spectral shape, but the solar X-ray spectrum during comet observations is highly dependent on the solar conditions at the time of detection. It is therefore important to determine the real-time solar X-ray intensities during observations and to scale the modeled SF cometary spectra to these values.…”

Section: Solar Intensitymentioning

confidence: 99%

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Cometary emissions induced by scattering and fluorescence of solar X-rays

Snios

Lewkow

Kharchenko

2014

A&A

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To establish the nature of cometary X-ray emissions above 1 keV, detailed modeling of scattering and fluorescence of solar X-rays by a cometary atmosphere is carried out over the 0.3−3.0 keV photon energy range. Computations of the X-ray emissions are performed for different distributions of the cometary neutral gas, dust, and ice grains, with an emphasis placed on nano-sized particles. The calculated emission spectra of energetic photons above 1 keV are compared to cometary observations performed by the Chandra X-ray Observatory, and emission contributions solely from cometary neutral gas are found to be an insufficient X-ray production mechanism. Further comparison between the developed model and observational data also establishes an upper limit on dust and ice nanoparticle density distributions in cometary atmospheres. In addition, similarities in spectral shape above 1 keV observed between cometary emissions, Jovian disk emissions, and scattered solar X-ray spectra during solar flare events are discussed in detail.

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Section: Comparison Of Ikeya-zhang To Jovian Disk As Evidence Of Scatsupporting

confidence: 72%

Section: Solar Intensitymentioning

confidence: 99%

Section: Solar Intensitymentioning

confidence: 99%

See 1 more Smart Citation

Cometary emissions induced by scattering and fluorescence of solar X-rays

Snios

Lewkow

Kharchenko

2014

A&A

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“…In both the Capella and HR 1099 HETGS spectra there is a feature near 7.17 Å , which in HR 1099 is of comparable strength to the Al xii resonance line. Solar X-ray spectra from the Solar Maximum Mission (SMM) and SOLEX also show no feature at 7.22 Å ; instead, they identify a feature at 7.17 Å as Al xiii (Phillips et al 1982;McKenzie et al 1985). The energy levels of Erickson (1977) and Mohr (1985) predict wavelengths of 7.171 and 7.176 Å for the 2 S 1/2 -2 P 3/2 and 2 S 1/2 -2 P 1/2 transitions, respectively.…”

Section: -(A)mentioning

confidence: 99%

Chandra,Extreme Ultraviolet Explorer, and Very Large Array Observations of the Active Binary System σ²Coronae Borealis

Osten

Ayres

Brown

et al. 2003

ApJ

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We present the results of a coordinated observing campaign on the short-period RS CVn binary 2 Coronae Borealis (F6V þ G0V; P orb ¼ 1:14 days) with the Very Large Array, the Extreme Ultraviolet Explorer, and the Chandra X-Ray Observatory High-Energy Transmission Grating Spectrometer. The radio emission is consistent with previously determined quiescent gyrosynchrotron properties. Multiple flares were seen with Extreme Ultraviolet Explorer, five occurring within two consecutive orbital periods. The first of these flares was observed with Chandra. The Chandra observations of 2 CrB showed no systematic variations of line fluxes, widths, or Doppler shifts with orbital phase, nor any response in line width or offset due to the flare. This is consistent with both stars being equally active coronal emitters. We have developed a self-consistent method of spectral analysis to derive information from the line and continuum emissions concerning the distribution of plasma with temperature and elemental abundances. A bimodal temperature distribution is appropriate for both quiescent and flare intervals, with a stable peak at 6-8 MK and another variable enhancement at higher temperatures, with evidence for significant contribution from temperatures up to 50 MK during the flare, compared to 30 MK during quiescence. The iron abundance is subsolar during quiescence but is enriched by about a factor of 2 during a large flare seen with Chandra. The noble gas elements neon and argon show elevated abundances with respect to iron, but there is no clear evidence for any first ionization potential-based abundance pattern during quiescence or the flare. We have determined coronal electron densities from the helium-like ions O vii, Ne ix, Mg xi, and Si xiii, which imply densities !10 10 cm À3 . There is a small enhancement in the electron densities derived for the flare, but it is not statistically significant. We call attention to electron temperature constraints provided by the ratios of 1s 2 1 S 0 -1snp 1 P 1 transitions of the helium-like ions O vii, Ne ix, Mg xi, and Si xiii. The derived coronal electron pressures change by 1-2 orders of magnitude over a 25% change in temperature, implying nonisobaric coronal conditions. We find no evidence for significant departures from the effectively thin coronal assumption. The electron densities inferred from the soft X-ray spectra are inconsistent with cospatial gyrosynchrotron emission; further observations are necessary to discriminate the relative locations of the radio and soft X-ray-emitting plasma.

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“…FeXXIII, Be-like Fe ion, is observed in fusion plasma at around T e ∼1keV as well as astrophysical plasmas, such as the solar corona and flares [1], and the intracluster gas [2].…”

Section: Introductionmentioning

confidence: 99%

UV and x-ray spectral lines of Fe XXIII ion for plasma diagnostics

Murakami

Katō

1996

Phys. Scr.

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We have calculated X-ray and UV spectra of Be-like Fe (FeXXIII) ion in collisional radiative model including all fine-structure transitions among the 2s 2 , 2s2p, 2p 2 , 2snl, and 2pnl ′ levels where n = 3 and 4, adopting data for the collision strengths by Zhang & Sampson (1992) and by Sampson, Goett, & Clark (1984). Some line intensity ratios can be used for the temperature diagnostics. We show 5 ratios in UV region and 9 ratios in X-ray region as a function of electron temperature and density at 0.3keV < ∼ T e < ∼ 10keVand n e = 1 − 10 25 cm −3 . The effect of cascade in these line ratios and in the level population densities are discussed.

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The solar coronal X-ray spectrum from 5.5 to 12 A

Cited by 52 publications

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Cometary emissions induced by scattering and fluorescence of solar X-rays

Cometary emissions induced by scattering and fluorescence of solar X-rays

Chandra,Extreme Ultraviolet Explorer, and Very Large Array Observations of the Active Binary System σ²Coronae Borealis

UV and x-ray spectral lines of Fe XXIII ion for plasma diagnostics

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The solar coronal X-ray spectrum from 5.5 to 12 A

Cited by 52 publications

References 0 publications

Cometary emissions induced by scattering and fluorescence of solar X-rays

Cometary emissions induced by scattering and fluorescence of solar X-rays

Chandra,Extreme Ultraviolet Explorer, and Very Large Array Observations of the Active Binary System σ2Coronae Borealis

UV and x-ray spectral lines of Fe XXIII ion for plasma diagnostics

Contact Info

Product

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Chandra,Extreme Ultraviolet Explorer, and Very Large Array Observations of the Active Binary System σ²Coronae Borealis