Table · dataset · 2022
QSO J1721+8842 spectra
Listed in IVOA Registry (Virtual Observatory)
High-redshift binary quasars provide key insights into mergers and quasar activity, and are useful tools for probing the spatial kinematics and chemistry of galaxies along the line-of-sight.
Description
However, only three sub-10-kpc binaries have been confirmed above z=1. Gravitational lensing would provide a way to easily resolve such binaries, study them in higher resolution, and provide more sightlines, though the required alignment with a massive foreground galaxy is rare.
Through image deconvolution of StanCam Nordic Optical Telescope (NOT) monitoring data, we reveal two further point sources in the known, z~2.38, quadruply lensed quasar (quad), J1721+8842. An ALFOSC/NOT long-slit spectrum shows that the brighter of these two sources is a quasar with z=2.369+/-0.007 based on the CIII] line, while the CIII] redshift of the quad is z=2.364+/-0.003. Lens modelling using point source positions rules out a single source model, favouring an isothermal lens mass profile with two quasar sources separated by ~6.0kpc (0.73") in projection.
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Given the resolving ability from lensing and current lensed quasar statistics, this discovery suggests a large population of undiscovered, unlensed sub-10-kpc binaries. We also analyse spectra of two images of the quad, showing narrow Ly{alpha} emission within the trough of a proximate damped Lyman-{alpha} absorber (PDLA). An apparent mismatch between the continuum and narrow line flux ratios provides a new potential tool for simultaneously studying microlensing and the quasar host galaxy.
Signs of the PDLA are also seen in the second source, however a deeper spectrum is still required to confirm this. Thanks to the multiple lines-of-sight from lensing and two quasar sources, this system offers simultaneous sub-parsec and kpc-scale probes of a PDLA.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/657/A113 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2022A&A...657A.113L ui.adsabs.harvard.edu/abs/2022A%26A...657A.113L ↗
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/657/a113 ↗
catalogue entry · from IVOA Registry
Topics
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Image 75%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/a+a/657/a113 | 12 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].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 |