The Ly α and Ly β Profiles in Solar Prominences and Prominence Fine Structure

Vial, J. C.; Ebadi, H.; Ajabshirizadeh, A.

doi:10.1007/s11207-007-9080-9

Cited by 18 publications

(27 citation statements)

References 26 publications

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“…Such opposite asymmetries of different Lyman lines at the same position in the observed prominence were noticed by e.g. Vial et al (2007). Figures 6 and 7 show histograms of the ratios of the specific intensities in the peaks of the Lyman-α and Lyman-β, and Lyman-γ and Lyman-δ line profiles, respectively.…”

Section: Red To Blue Peak Intensity Ratiosupporting

confidence: 51%

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Statistical comparison of the observed and synthetic hydrogen Lyman line profiles in solar prominences

Gunár¹,

Schwartz²,

Schmieder

et al. 2010

A&A

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Aims. We analyse a unique set of prominence SOHO/SUMER Lyman spectra by comparing it with synthetic spectra obtained by 2D multi-thread prominence fine-structure models. Methods. We employed a novel statistical approach to the analysis of the observed and synthetic Lyman spectra. We compared the statistical distributions of the line properties of the observed and synthetic Lyman spectra using a set of four statistical criteria. Results. We demonstrate the very good agreement between the observed Lyman spectra and synthetic spectra obtained by modelling. Conclusions. Our set of statistical criteria is well-suited to analyses of the prominence Lyman spectra because of its sensitivity to a number of different parameters governing the conditions in the prominence fine structures.

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Section: Red To Blue Peak Intensity Ratiosupporting

confidence: 51%

“…Vial et al 2007). Gunár et al (2008) uses the multi-thread method for modelling the prominence fine structures to obtain the synthetic Lyman line profiles with asymmetries comparable to the observed ones.…”

Section: Red To Blue Peak Intensity Ratiomentioning

confidence: 99%

Statistical comparison of the observed and synthetic hydrogen Lyman line profiles in solar prominences

Gunár¹,

Schwartz²,

Schmieder

et al. 2010

A&A

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“…Thus the insignificant difference among the three values seems to suggest that the ratio of Ly-α and Ly-β intensities is independent of magnetic field strength. Recently, and also based on a SUMER observation, Vial et al (2007) obtained varying Ly-α/Ly-β radiance (in the energy unit) ratios of 96, 183, and 181 in different parts of a prominence. They were explained as relating to the fine structures in prominences.…”

Section: Ratio Between Ly-α and Ly-β Intensitiesmentioning

confidence: 99%

“…This work also predicted that the Ly-α profiles may exhibit an asymmetry opposite to those of higher Lyman lines. The ratio of Ly-α/Ly-β is also very sensitive to the physical and geometrical properties of the fine structures in prominences, and the fluctuations of this ratio are believed to relate to such fine structures (Vial et al 2007). The OSO 8 observation yielded a value of 65 (in the energy unit) for this ratio (Vial 1982), while a recent SUMER observation revealed a different ratio (96, 183, and 181, in the energy unit) in different parts of a prominence (Vial et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Lyman-α and Lyman-β spectral radiance profiles in the quiet Sun

Curdt

Marsch

Schühle

2009

A&A

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Aims. We extend earlier work by studying the line profiles of the hydrogen Lyman-α and Lyman-β lines in the quiet Sun. They were obtained quasi-simultaneously in a raster scan with a size of about 150 × 120 near disk center. Methods. The self-reversal depths of the Ly-α and Ly-β profiles. we are quantified by measuring the maximum spectral radiances of the two horns and the minimum spectral radiance of the central reversal. The information on the asymmetries of the Ly-α and Ly-β profiles is obtained through calculating the 1st and 3rd-order moments of the line profiles. By comparing maps of self-reversal depths and the moments with radiance images of the Lyman lines, photospheric magnetograms, and Dopplergrams of two other optically thin lines, we studied the spatial distribution of the Ly-α and Ly-β profiles with different self-reversal depths, and investigated the relationship between profile asymmetries and flows in the solar atmosphere. Results. We find that the emissions of the Lyman lines tend to be more strongly absorbed in the internetwork, as compared to those in the network region. Almost all of the Ly-α profiles are self-reversed, while about 17% of the Ly-β profiles are not reversed. The ratio of Ly-α and Ly-β intensities seems to be independent of the magnetic field strength. Most Ly-α profiles are stronger in the blue horn, whereas most Ly-β profiles are stronger in the red horn. However, the opposite asymmetries of Ly-α and Ly-β are not correlated pixelto-pixel. We also confirm that when larger transition-region downflows are present, the Ly-α and Ly-β profiles are more enhanced in the blue and red horns, respectively. The first-order moment of Ly-β, which reflects the combined effects of the profile asymmetry and motion of the emitting material, strongly correlates with the Doppler shifts of the Si iii and O vi lines, while this correlation is much weaker for Ly-α. Our analysis shows that both Ly-α and Ly-β might be more redshifted if stronger transition-region downflows are present. We also find that the observed average Ly-β profile is redshifted with respect to its rest position.

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“…recorded by SUMER spectrograph mounted on SoHO space telescope) wavelength calibration is done with the help of some stable photospheric spectral lines (Vial et al 2007). But in the current work, we use crosscorrelation analysis in order to do wavelength calibration on our observed spectra.…”

Section: The Wavelength Calibrationmentioning

confidence: 99%

Spectral atlases of the Sun from 3980 to 7100 Å at the center and at the limb

Fathivavsari¹,

Ajabshirizadeh²,

Koutchmy³

2014

Astrophys Space Sci

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In this work, we present digital and graphical atlases of spectra of both the solar disk-center and of the limb near the Solar poles using data taken at the UTS−IAP & RIAAM (the University of Tabriz Siderostat, telescope and spectrograph jointly developed with the Institut d'Astrophysique de Paris and Research Institute for Astronomy and Astrophysics of Maragha). High resolution and high signal-to-noise ratio (SNR) CCDslit spectra of the sun for 2 different parts of the disk, namely for µ = 1.0 (solar center) & for µ = 0.3 (solar limb) are provided and discussed. While there are several spectral atlases of the solar disk-center, this is the first spectral atlas ever produced for the solar limb at this spectral range. The resolution of the spectra is about R ∼ 70 000 (∆λ ∼ 0.09Å) with the signal-tonoise ratio (SNR) of 400−600. The full atlas covers the 3980 to 7100Å spectral regions and contains 44 pages with three partial spectra of the solar spectrum put on each page to make it compact. The difference spectrum of the normalized solar disk-center and the solar limb is also included in the graphic presentation of the atlas to show the difference of line profiles, including far wings. The identification of the most significant solar lines is included in the graphic presentation of the atlas. Telluric lines are producing a definite signature on the difference spectra which is easy to notice. At the end of this paper we present only two sample pages of the whole atlas while the graphic presentation of the whole atlas along with its ASCII file can be accessed via the ftp server of the CDS in Strasbourg via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via this link 1 .

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The Ly α and Ly β Profiles in Solar Prominences and Prominence Fine Structure

Cited by 18 publications

References 26 publications

Statistical comparison of the observed and synthetic hydrogen Lyman line profiles in solar prominences

Statistical comparison of the observed and synthetic hydrogen Lyman line profiles in solar prominences

Hydrogen Lyman-α and Lyman-β spectral radiance profiles in the quiet Sun

Spectral atlases of the Sun from 3980 to 7100 Å at the center and at the limb

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