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Resource Record Summary

Catalog Service:
SDSS and DES long-term extreme variability QSOs

Short name: J/ApJ/854/160
IVOA Identifier: ivo://CDS.VizieR/J/ApJ/854/160
DOI (Digital Object Identifier): 10.26093/cds/vizier.18540160
Publisher: CDSivo://CDS[Pub. ID]
More Info: https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/854/160
VO Compliance: Level 2: This is a VO-compliant resource.
Status: active
Registered: 2019 Jan 03 08:10:09Z
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Description


We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ~1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L_bol_~10^45^-10^47^erg/s and L/L_Edd_~0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ~30%-50% among all g<~22 quasars over a baseline of ~15yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.

More About this Resource

About the Resource Providers

This section describes who is responsible for this resource

Publisher: CDSivo://CDS[Pub. ID]

Creators:
Rumbaugh N.Shen Y.Morganson E.Liu X.Banerji M.McMahon R.G.Abdalla F.B.Benoit-Levy A.Bertin E.Brooks D.Buckley-Geer E.Capozzi D.Carnero Rosell A.Carrasco Kind M.Carretero J.Cunha C.E.D'Andrea C.B.da Costa L.N.DePoy D.L.Desai S.Doel P.Frieman J.Garcia-Bellido J.Gruen D.Gruendl R.A.Gschwend J.Gutierrez G.Honscheid K.James D.J.Kuehn K.Kuhlmann S.Kuropatkin N.Lima M.Maia M.A.G.Marshall J.L.Martini P.Menanteau F.Plazas A.A.Reil K.Roodman A.Sanchez E.Scarpine V.Schindler R.Schubnell M.Sheldon E.Smith M.Soares-Santos M.Sobreira F.Suchyta E.Swanson M.E.C.Walker A.R.Wester W.

Contact Information:
X CDS support team
Email: cds-question at unistra.fr
Address: CDS
Observatoire de Strasbourg
11 rue de l'Universite
F-67000 Strasbourg
France

Status of This Resource

This section provides some status information: the resource version, availability, and relevant dates.

Version: n/a
Availability: This is an active resource.
  • This service provides only public data.
Relevant dates for this Resource:
  • Updated: 2019 Jan 09 14:08:42Z
  • Created: 2019 Jan 03 08:10:09Z

This resource was registered on: 2019 Jan 03 08:10:09Z
This resource description was last updated on: 2021 Oct 21 00:00:00Z

What This Resource is About

This section describes what the resource is, what it contains, and how it might be relevant.

Resource Class: CatalogService
This resource is a service that provides access to catalog data. You can extract data from the catalog by issuing a query, and the matching data is returned as a table.
Resource type keywords:
  • Catalog
Subject keywords:
  • Photometry
  • Optical astronomy
  • Sloan photometry
  • Quasars
  • Redshifted
  • Spectroscopy
  • Surveys
Intended audience or use:
  • Research: This resource provides information appropriate for supporting scientific research.
More Info: https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/854/160 Literature Reference: 2018ApJ...854..160R

Related Resources:

Other Related Resources
TAP VizieR generic service(IsServedBy) ivo://CDS.VizieR/TAP [Res. ID]
Conesearch service(IsServedBy)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010) ivo://CDS.VizieR/VII/260 [Res. ID]

Data Coverage Information

This section describes the data's coverage over the sky, frequency, and time.

Wavebands covered:

  • Optical

Rights and Usage Information

This section describes the rights and usage information for this data.

Rights:

Available Service Interfaces

Custom Service

This is service that does not comply with any IVOA standard but instead provides access to special capabilities specific to this resource.

VO Compliance: Level 2: This is a VO-compliant resource.
Available endpoints for this service interface:
Custom Service

This is service that does not comply with any IVOA standard but instead provides access to special capabilities specific to this resource.

VO Compliance: Level 2: This is a VO-compliant resource.
Available endpoints for this service interface:
  • URL-based interface: http://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/854/160
Table Access Protocol - Auxiliary ServiceXX

This is a standard IVOA service that takes as input an ADQL or PQL query and returns tabular data.

VO Compliance: Level 2: This is a VO-compliant resource.
Available endpoints for the standard interface:
  • http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Simple Cone SearchXXSearch Me

This is a standard IVOA service that takes as input a position in the sky and a radius and returns catalog records with positions within that radius.

VO Compliance: Level 2: This is a VO-compliant resource.
Description:
Cone search capability for table J/ApJ/854/160/table2 (The "extreme variability quasar" (EVQ) sample)
Available endpoints for the standard interface:
  • http://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/854/160/table2?
Maximum search radius accepted: 180.0 degrees
Maximum number of matching records returned: 50000
This service supports the VERB input parameter:
Use VERB=1 to minimize the returned columns or VERB=3 to maximize.


Developed with the support of the National Science Foundation
under Cooperative Agreement AST0122449 with the Johns Hopkins University
The NAVO project is a member of the International Virtual Observatory Alliance

This NAVO Application is hosted by the Space Telescope Science Institute

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