Table · dataset · 2026
Extreme emission-line galaxies at z~4-9
Listed in IVOA Registry (Virtual Observatory)
We investigate the properties of extreme emission line galaxies (EELGs) at z=4-9 and their role in reionization.
Description
Compact, low-mass galaxies with intense optical emission lines are linked to elevated specific star formation rates (sSFRs) and recent bursts of star formation. Feedback in these systems may enable the leakage of ionizing radiation into the intergalactic medium.
Using JWST/NIRSpec spectroscopy from the CAPERS, CEERS, and RUBIES surveys, we compile 160 NIRCam-selected EELGs in the EGS field. These galaxies show extreme rest-frame equivalent widths (EWs), with a median EW([OIII/Hbeta])=1616{AA} and EW(Halpha)=763{AA}. They are low-mass (median log(M*/M_{sun}_)=8.26) with high sSFRs (median 43Gyr^-1^), above the z~6 main sequence.
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UV slopes are diverse, with a median value of beta=-2.0, and only 7% have extremely blue continua (beta<-2.6). Emission-line diagnostics suggest stellar populations as the primary ionizing source, although an AGN fraction of 14% {cannot be entirely ruled out. These galaxies are efficient ionizing photon producers, with median log(xi_ion_[Hz/erg])={25.37}, exceeding typical values at similar redshifts.
Escape fractions, however, are heterogeneous: 16% of EELGs at z<7 show escape fractions >5% for both Lyalpha and LyC photons, while 82% lack detectable Lya emission. The median inferred LyC escape fraction is modest (5%) but enhanced in compact super-Eddington systems with sSFR>25Gyr^-1^. These results indicate that EELGs contribute approximately 16-40% of the total ionizing emissivity required to sustain hydrogen reionization.
EELGs are extremely compact, with a median effective radius of 0.49kpc, and exhibit a recent star-formation burst. Our analysis indicates that sSFR and star-formation rate surface density are the primary drivers of their extreme emission line strengths.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A152 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2026A&A...708A.152L ui.adsabs.harvard.edu/abs/2026A%26A...708A.152L ↗
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/708/a152 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Infrared
- From keywords
- Astronomy & Astrophysics
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/708/a152 | 14 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| 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 | |
| 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 |