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Start Over Subject ultraviolet astronomy Validation Level 2
1. 3060-3700{AA} spectra analysis of early-type stars
ID:
ivo://CDS.VizieR/J/ApJS/216/22
Title:
3060-3700{AA} spectra analysis of early-type stars
Short Name:
J/ApJS/216/22
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comprehensive and sensitive unbiased survey of interstellar features in the near-UV range (3050-3700{AA}). We combined a large number of VLT/UVES archival observations of a sample of highly reddened early-type stars -typical diffuse interstellar band targets- and unreddened standards. We stacked the individual observations to obtain a reddened "superspectrum" in the interstellar rest frame with a signal-to-noise ratio exceeding 1500. We compared this to the analogous geocentric and stellar rest frame superspectra as well as to an unreddened superspectrum to find interstellar absorption features. We find 30 known features (11 atomic and 19 molecular) and tentatively detect up to 7 new interstellar absorption lines of unknown origin. Our survey is sensitive to narrow and weak features; telluric residuals preclude us from detecting broader features. For each sightline, we measured fundamental parameters (radial velocities, line widths, and equivalent widths) of the detected interstellar features. We also revisit upper limits for the column densities of small, neutral polycyclic aromatic hydrocarbon molecules that have strong transitions in this wavelength range.
2. Absorption lines in QSO 0000-2619
ID:
ivo://CDS.VizieR/J/A+A/318/347
Title:
Absorption lines in QSO 0000-2619
Short Name:
J/A+A/318/347
Date:
21 Oct 2021
Publisher:
CDS
Description:
We give the list of absorption lines in the high resolution (FWHM=13 km/s) spectrum of the z=4.12 QSO 0000-2619. The first table contains the lines of the Lyman-alpha forest, while in the second table the lines of the metal systems are listed.
3. Absorption systems of HS 1700+6416
ID:
ivo://CDS.VizieR/J/A+A/294/377
Title:
Absorption systems of HS 1700+6416
Short Name:
J/A+A/294/377
Date:
21 Oct 2021
Publisher:
CDS
Description:
Ultraviolet observations of the high-redshift quasat HS 1700+6416 were obtained with the Faint Object Spectrograph (FOS) onboard the Hubble Space Telescope (HST) in the range 115-328nm, on 1991-12-13/14 and 1992-02-13/14 at a resolution R=1300. The identification of the numerous absoprtion lines provides evidence for 15 heavy-element absorption systems, among them 7 Lyman Limit systems (LLS).
4. Absorption toward PG 1116+215
ID:
ivo://CDS.VizieR/J/ApJS/155/351
Title:
Absorption toward PG 1116+215
Short Name:
J/ApJS/155/351
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) observations of the intergalactic absorption toward QSO PG 1116+215 in the 900-3000{AA} spectral region.
5. Abundances in 6 metal-poor stars
ID:
ivo://CDS.VizieR/J/ApJ/857/2
Title:
Abundances in 6 metal-poor stars
Short Name:
J/ApJ/857/2
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new abundances derived from CuI, CuII, ZnI, and ZnII lines in six warm (5766<=T_eff_<=6427K), metal-poor (-2.50<=[Fe/H]<=-0.95) dwarf and subgiant (3.64<=logg<=4.44) stars. These abundances are derived from archival high-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and ground-based optical spectra from several observatories. Ionized Cu and Zn are the majority species, and abundances derived from CuII and ZnII lines should be largely insensitive to departures from local thermodynamic equilibrium (LTE). We find good agreement between the [Zn/H] ratios derived separately from ZnI and ZnII lines, suggesting that departures from LTE are, at most, minimal (<~0.1dex). We find that the [Cu/H] ratios derived from CuII lines are 0.36+/-0.06dex larger than those derived from CuI lines in the most metal-poor stars ([Fe/H]{<}-1.8), suggesting that LTE underestimates the Cu abundance derived from CuI lines. The deviations decrease in more metal-rich stars. Our results validate previous theoretical non-LTE calculations for both Cu and Zn, supporting earlier conclusions that the enhancement of [Zn/Fe] in metal-poor stars is legitimate, and the deficiency of [Cu/Fe] in metal-poor stars may not be as large as previously thought.
6. Abundances in normal late-B and HgMn stars
ID:
ivo://CDS.VizieR/J/A+A/274/335
Title:
Abundances in normal late-B and HgMn stars
Short Name:
J/A+A/274/335
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
7. Abundances of metal-poor star HD 94028
ID:
ivo://CDS.VizieR/J/ApJ/821/37
Title:
Abundances of metal-poor star HD 94028
Short Name:
J/ApJ/821/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed analysis of the composition and nucleosynthetic origins of the heavy elements in the metal-poor ([Fe/H]=-1.62+/-0.09) star HD 94028. Previous studies revealed that this star is mildly enhanced in elements produced by the slow neutron-capture process (s process; e.g., [Pb/Fe]=+0.79+/-0.32) and rapid neutron-capture process (r process; e.g., [Eu/Fe]=+0.22+/-0.12), including unusually large molybdenum ([Mo/Fe]= +0.97+/-0.16) and ruthenium ([Ru/Fe]=+0.69+/-0.17) enhancements. However, this star is not enhanced in carbon ([C/Fe]=-0.06+/-0.19). We analyze an archival near-ultraviolet spectrum of HD 94028, collected using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, and other archival optical spectra collected from ground-based telescopes. We report abundances or upper limits derived from 64 species of 56 elements. We compare these observations with s-process yields from low-metallicity AGB evolution and nucleosynthesis models. No combination of s- and r-process patterns can adequately reproduce the observed abundances, including the super-solar [As/Ge] ratio (+0.99+/-0.23) and the enhanced [Mo/Fe] and [Ru/Fe] ratios. We can fit these features when including an additional contribution from the intermediate neutron-capture process (i process), which perhaps operated through the ingestion of H in He-burning convective regions in massive stars, super-AGB stars, or low-mass AGB stars. Currently, only the i process appears capable of consistently producing the super-solar [As/Ge] ratios and ratios among neighboring heavy elements found in HD 94028. Other metal-poor stars also show enhanced [As/Ge] ratios, hinting that operation of the i process may have been common in the early Galaxy.
8. Abundances of 3 supergiants in Sextans A
ID:
ivo://CDS.VizieR/J/AJ/127/2723
Title:
Abundances of 3 supergiants in Sextans A
Short Name:
J/AJ/127/2723
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the abundance analyses of three isolated A-type supergiant stars in the dwarf irregular galaxy Sextans A (=DDO 75) from high-resolution spectra obtained with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the Kueyen telescope (UT2) of the ESO Very Large Telescope (VLT). Detailed model atmosphere analyses have been used to determine the stellar atmospheric parameters and the elemental abundances of the stars.
9. Abundances of UV-bright stars
ID:
ivo://CDS.VizieR/J/A+A/423/353
Title:
Abundances of UV-bright stars
Short Name:
J/A+A/423/353
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have derived the chemical composition of nine UV-bright stars belonging to five Galactic globular clusters of various metallicities ([Fe/H] from -1.0 to -2.4dex). The analyses are based on high resolution spectra obtained with the UV-Visual Echelle Spectrograph (UVES) at VLT-UT2.
10. A catalog of coronal "EIT wave" transients
ID:
ivo://CDS.VizieR/J/ApJS/183/225
Title:
A catalog of coronal "EIT wave" transients
Short Name:
J/ApJS/183/225
Date:
21 Oct 2021
Publisher:
CDS
Description:
Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT) data have been visually searched for coronal "EIT wave" transients over the period beginning from 1997 March 24 and extending through 1998 June 24. The dates covered start at the beginning of regular high-cadence (more than 1 image every 20 minutes) observations, ending at the four-month interruption of SOHO observations in mid-1998. One hundred and seventy six events are included in this catalog. The observations range from "candidate" events, which were either weak or had insufficient data coverage, to events which were well defined and were clearly distinguishable in the data. Included in the catalog are times of the EIT images in which the events are observed, diagrams indicating the observed locations of the wave fronts and associated active regions, and the speeds of the wave fronts. The measured speeds of the wave fronts varied from less than 50 to over 700km/s with "typical" speeds of 200-400km/s.