Extreme ultraviolet spectrum of a solar active region from SERTS

Thomas, R. J.; Neupert, W. M.

doi:10.1086/191944

Cited by 243 publications

(213 citation statements)

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“…For example, the Goddard Solar Extreme Ultraviolet Rocket Telescope and Spectrograph (SERTS) has been flown several times since 1989 and has produced data of excellent spectral resolution, mostly of active regions. The SERTS-89 (Thomas & Neupert 1994; hereafter TN94) covered the 170−225 Å range in second order and the 235−450 Å range in first order. The SERTS-97 (Brosius et al 2000) covered the 300−353 Å spectral region.…”

Section: Solar Euv Spectramentioning

confidence: 99%

Benchmarking atomic data for astrophysics: Fe xi

Zanna¹

2010

A&A

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High-resolution spectroscopic observations of the solar corona and laboratory measurements are used to review all the line identifications for Fe xi, from the EUV to the visible. The results of the atomic structure and scattering calculations are presented elsewhere, while detailed comparisons between observed and predicted wavelengths and intensities are discussed here. All the brightest EUV lines in the solar corona are now finally firmly identified. Several new identifications are proposed, in particular, coronal forbidden lines. The previously-known density-diagnostics are confirmed. New and important temperature diagnostics are presented, and the presence of blends highlighted.

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Section: Solar Euv Spectramentioning

confidence: 99%

Benchmarking atomic data for astrophysics: Fe xi

Zanna¹

2010

A&A

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“…The spectra of loop structures in an active region, studied by Doyle et al (1985a) with the help of Skylab data, indicated a rather constant electron density up to temperatures of several million kelvin. A recent spectrum of an active region observed by SERTS was presented by Thomas and Neupert (1994). Cook et al (1983) performed a detailed study of localized emission enhancements with HRTS.…”

Section: Active Regionsmentioning

confidence: 99%

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

et al. 2007

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In Part I of this review, the concepts of solar vacuum-ultraviolet (VUV) observations were outlined together with a discussion of the space instrumentation used for the investigations. A section on spectroradiometry provided some quantitative results on the solar VUV radiation without considering any details of the solar phenomena leading to the radiation. Here, in Part II, we present solar VUV observations over the last decades and their interpretations in terms of the plasma processes and the parameters of the solar atmosphere, with emphasis on the spatial and thermal structures of the chromosphere, transition region and corona of the quiet Sun. In addition, observations of active regions, solar flares and prominences are included as well as of small-scale events. Special sections are devoted to the elemental composition of the solar atmosphere and theoretical considerations on the heating of the corona and the generation of the solar wind.

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“…For example, many emission features have been detected and extensively studied in the 311-437 Å region by the SERTS rocket spectrograph (Thomas & Neupert 1994), while the S082A and S-055 instruments on Skylab found several Mg  transitions spanning 315−783 Å in a number of solar features including a sunspot, active region and flares (Foster et al 1997a). Also, SUMER spectra have highlighted the existence of Mg  lines lying in the 762−790 Å wavelength region (Landi et al 2002).…”

Section: Emission Line Intensitiesmentioning

confidence: 99%

“…For example, the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrograph on board Solar and Heliospheric Observatory (SOHO) detected emission lines of Mg  lying within the extreme-ultraviolet (EUV) spectral region (Curdt et al 2001), while the 1989 and 1997 Solar EUV Rocket Telescope and Spectrograph (SERTS) active region spectra contain several Mg  features in the 300-450 Å region (Thomas & Neupert 1994;Brosius et al 2000). Measurements of solar Mg  lines have also been obtained with the S-055 and S082A instruments on Skylab (Vernazza & Reeves 1978;Foster et al 1997a).…”

Section: Introductionmentioning

confidence: 99%

Electron impact excitation of Mg VIII

Grieve

Ramsbottom

Keenan

2013

A&A

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Context. Mg  emission lines are observed in a range of astronomical objects such as the Sun, other cool stars and in the coronal line region of Seyfert galaxies. Under coronal conditions Mg  emits strongly in the extreme ultraviolet (EUV) and soft X-ray spectral regions which makes it an ideal ion for plasma diagnostics. Aims. Two theoretical atomic models, consisting of 125 fine structure levels, are developed for the Mg  ion. The 125 levels arise from the 2s 2 2p, 2s2p 2 , 2p 3 , 2s 2 3s, 2s 2 3p, 2s 2 3d, 2s2p3s, 2s2p3p, 2s2p3d, 2p 2 3s, 2p 2 3p and 2p 2 3d configurations. Electron impact excitation collision strengths and radiative transition probabilities are calculated for both Mg  models, compared with existing data, and the best model selected to generate a set of theoretical emission line intensities. The EUV lines, covering 312-790 Å, are compared with existing solar spectra (SERTS-89 and SUMER), while the soft X-ray transitions (69-97 Å) are examined for potential density diagnostic line ratios and also compared with the limited available solar and stellar observational data. Methods. The R-matrix codes Breit-Pauli RMATRXI and RMATRXII are utilised, along with the PSTGF code, to calculate the collision strengths for two Mg  models. Collision strengths are averaged over a Maxwellian distribution to produce the corresponding effective collision strengths for use in astrophysical applications. Transition probabilities are also calculated using the CIV3 atomic structure code. The best data are then incorporated into the modelling code CLOUDY and line intensities generated for a range of electron temperatures and densities appropriate to solar and stellar coronal plasmas.Results. The present effective collision strengths are compared with two previous calculations. Good levels of agreement are found with the most recent, but there are large differences with the other for forbidden transitions. The resulting line intensities compare favourably with the observed values from the SERTS-89 and SUMER spectra. Theoretical soft X-ray emission lines are presented and several density diagnostic line ratios examined, which are in reasonable agreement with the limited observational data available.

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Extreme ultraviolet spectrum of a solar active region from SERTS

Cited by 243 publications

References 1 publication

Benchmarking atomic data for astrophysics: Fe xi

Benchmarking atomic data for astrophysics: Fe xi

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

Electron impact excitation of Mg VIII

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