Table · dataset · 2009
Photometric selection of quasars from SDSS. II.
Listed in IVOA Registry (Virtual Observatory)
We present a catalog of 1172157 quasar candidates selected from the photometric imaging data of the Sloan Digital Sky Survey (SDSS).
Description
The objects are all point sources to a limiting magnitude of i=21.3 from 8417deg^2^ of imaging from SDSS Data Release 6 (DR6). This sample extends our previous catalog by using the latest SDSS public release data and probing both ultraviolet (UV)-excess and high-redshift quasars.
While the addition of high-redshift candidates reduces the overall efficiency (quasars:quasar candidates) of the catalog to ~80%, it is expected to contain no fewer than 850000 bona fide quasars, which is ~8 times the number of our previous sample and ~10 times the size of the largest spectroscopic quasar catalog. Cross-matching between our photometric catalog and spectroscopic quasar catalogs from both the SDSS and 2dF survey yields 88879 spectroscopically confirmed quasars.
Read the rest (2 more)
For judicious selection of the most robust UV-excess sources (~500000 objects in all), the efficiency is nearly 97% -more than sufficient for detailed statistical analyses. The catalog's completeness to type 1 (broad-line) quasars is expected to be no worse than 70%, with most missing objects occurring at z<0.7 and 2.5<z<3.0. In addition to classification information, we provide photometric redshift estimates (typically good to {Delta}z+/-0.3[2{sigma}]) and cross-matching with radio, X-ray, and proper-motion catalogs.
Finally, we consider the catalog's utility for determining the optical luminosity function of quasars and are able to confirm the flattening of the bright-end slope of the quasar luminosity function at z~4 as compared to z~2.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/180/67 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2009ApJS..180...67R ui.adsabs.harvard.edu/abs/2009ApJS..180...67R ↗
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/apjs/180/67 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Optical
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Imaging 75%
Provenance · 1 source records, 9 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/apjs/180/67 | 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:optical | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].local:modality:imaging | 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 |