Table · dataset · 2023
Unveiling weak radio quasar population at z>=4
Listed in IVOA Registry (Virtual Observatory)
We applied image stacking on empty field Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey maps centred on optically identified high-redshift quasars at z>=4 to uncover the hidden {mu}Jy radio emission in these active galactic nuclei (AGN).
Description
The median stacking procedure for the full sample of 2229 optically identified AGN uncovered an unresolved point source with an integrated flux density of 52{mu}Jy, with a signal-to-noise ratio ~10.
We co-added the individual image centre pixels to estimate the characteristic monochromatic radio power at 1.4GHz considering various values for the radio spectral index, revealing a radio population with P_1.4GHz_~10^24^W/Hz. Assuming that the entire radio emission originates from star-forming (SF) activity in the nuclear region of the host galaxy, we obtained an upper limit on the characteristic star formation rate, ~4200M_{sun}_/yr.
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The angular resolution of FIRST images is insufficient to distinguish between the SF and AGN origin of radio emission at these redshifts. However, a comparison with properties of individual sources from the literature indicates that a mixed nature is likely. Future very long baseline interferometry radio observations and ultradeep Square Kilometre Array surveys are expected to be sensitive enough to detect and resolve the central 1-10kpc region in the host galaxies, and thus discriminate between SF and AGN related emission.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/490/2542 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2019MNRAS.490.2542P ui.adsabs.harvard.edu/abs/2019MNRAS.490.2542P ↗
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/mnras/490/2542 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Radio
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Astronomical sciences 72% · Image 75%
Provenance · 1 source records, 10 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/mnras/490/2542 | 11 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 (72%) |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:radio | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].local:modality:image | enrichment · IVOA Registry | keyword-concept-rules@1.0.0 | title+description (75%) |
| 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 |