Lensed and extended quasars Virtual Observatory Resource

Authors
  1. Williams P.
  2. Agnello A.
  3. Treu T.
  4. Published by
    CDS
Abstract

Wide-field photometric surveys enable searches of rare yet interesting objects, such as strongly lensed quasars or quasars with a bright host galaxy. Past searches for lensed quasars based on their optical and near-infrared properties have relied on photometric cuts and spectroscopic preselection (as in the Sloan Quasar Lens Search), or neural networks applied to photometric samples. These methods rely on cuts in morphology and colours, with the risk of losing many interesting objects due to scatter in their population properties, restrictive training sets, systematic uncertainties in catalogue-based magnitudes and survey-to-survey photometric variations. Here, we explore the performance of a Gaussian mixture model to separate point-like quasars, quasars with an extended host and strongly lensed quasars using grizpsf and model magnitudes and WISEW1, W2. The choice of optical magnitudes is due to their presence in all current and upcoming releases of wide-field surveys, whereas UV information is not always available. We then assess the contamination from blue galaxies and the role of additional features such as W3 magnitudes or psf-model terms as morphological information. As a demonstration, we conduct a search in a random 10 per cent of the SDSS footprint, and provide the catalogue of the 43 SDSS object with the highest 'lens' score in our selection that survive visual inspection, and are spectroscopically confirmed to host active nuclei. We inspect archival data and find images of 5/43 objects in the Hubble Legacy Archive, including two known lenses.

Keywords
  1. Quasars
  2. Gravitational lensing
Bibliographic source Bibcode
2017MNRAS.466.3088W
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/466/3088
IVOA Identifier IVOID
ivo://CDS.VizieR/J/MNRAS/466/3088

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/466/3088
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/466/3088
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/466/3088
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/466/3088/table2?
https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/466/3088/table2?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/466/3088/table2?
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/466/3088/table3?
https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/466/3088/table3?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/466/3088/table3?

History

2019-11-27T16:21:38Z
Resource record created
2019-11-27T16:21:38Z
Created
2020-05-04T11:13:16Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr