Table · dataset · 2026
Chemical composition in low-mass galaxies
Listed in IVOA Registry (Virtual Observatory)
We present Very Large Telescope/Xshooter spectrophotometric observations of eleven low-redshift (z<0.085) compact star-forming galaxies (the high O 32 sample).
Description
These galaxies are characterised by extremely high emission-line ratios, [O III]5007/[O II]3727, ranging from 11 to 42. Galaxies with such high ratios are promising candidates for leaking large amounts of Lyman continuum radiation.
They are characterised by low oxygen abundances, 12+log(O/H)=7.5-8.0, and low stellar masses, M*~10^6^-10^8^M_{sun}. We used strong emission lines of various ions in all spectra to derive helium and oxygen abundances and N/O, Ne/O, S/O, Cl/O, Ar/O, and Fe/O abundance ratios. We also derived macroscopic velocity dispersions, sigma(lambda), from various emission lines of different ions.
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We find that sigma(4861) of the Hbeta emission line increases with increasing stellar mass and decreasing O 32 ratio. In contrast, sigma(lambda)/sigma(4861) ratios for various lines are close to unity. Exceptions are the sigma(lambda)/sigma(4861) of two lines, HeII 4686 and HeI 10830, which are considerably higher than unity, and those of four lines, [OII] 3726, 3729, [SII] 6717, and 6731, for which sigma(lambda)/sigma(4861) is lower than unity.
The HeII 4686 and He I 10830 lines are likely produced in the inner parts of HII regions and are broadened by dynamical processes generated by massive stars, and, in the case of the HeI 10830 emission line, by radiative scattering. Emission in the [OII] and [SII] lines is produced mainly in the outer and likely more quieter parts of HII regions.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/712/A19 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2026A&A...712A..19I ui.adsabs.harvard.edu/abs/2026A%26A...712A..19I ↗
publication · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/j/a%2Ba/712/a19 ↗
catalogue entry · from IVOA Registry
Topics
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Astronomical sciences 73%
Provenance · 1 source records, 11 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/712/a19 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].anzsrc:group:5101 | enrichment · IVOA Registry | taxonomy-embedding@1.1.0 | title+keywords+description (73%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:infrared | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:optical | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:uv | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |