2.1.4 lens_candidates

This table contains the sources identified as possible gravitational lens candidates based on an analysis of the observations in the neighbourhood of a list of sources selected from a compilation of quasar candidates. Information about the catalogues from which these quasars proceed is given in the table of lens catalogue names.
For each source_id, a list of components found around that source is tabulated, together with some information about their position and flux as derived from the cluster of observations associated with each of them. These individual observations are provided in lens_observations.
A separate table lens_outliers compiles all those observations that could not be associated with a component around a given source_id, and that have therefore been discarded from the analysis.

Columns description:

solution_id : Solution Identifier (long)

All Gaia data processed by the Data Processing and Analysis Consortium comes tagged with a solution identifier. This is a numeric field attached to each table row that can be used to unequivocally identify the version of all the subsystems that were used in the generation of the data as well as the input data used. It is mainly for internal DPAC use but is included in the published data releases to enable end users to examine the provenance of processed data products. To decode a given solution ID visit https://gaia.esac.esa.int/decoder/solnDecoder.jsp

source_id : Unique source identifier (long)

A unique single numerical identifier of the source obtained from the Gaia DR3 main source catalogue (for a detailed description see gaiadr3.gaia_source.source_id).

name : The name of the gravitational lens candidate (string)

The gravitational lens candidate name, in the form DR3Gaiahhmmss.sss+/-ddmmss.ss, where hhmmss.sss and ddmmss.ss are the right ascension and declination respectively.

flag : GravLens flag (byte)

This flag provides information about the processing or scientific quality of the results of the GravLens chain for the source of interest. The flag checks two conditions:

1. 1.

   Whether the magnitude difference between the brightest and the faintest component of the system is larger than 5 mag.

2. 2.

   Whether the number of outlier observations (tabulated in lens_outlier) is larger than the number of valid observations (tabulated in lens_observation).

The flag then is coded in the following way:

• •

  0 when none of the conditions above are met.

• •

  1 when the first condition is met but not the second.

• •

  10 when the second condition is met but not the first.

• •

  11 when both conditions are met.

n_components : Number of components (int)

Number of components around the source_id obtained from the clustering algorithm applied in a fixed radius.

component_id : Index of the component for this source_id (int)

An index used to identify the various components found around this source_id. This number varies between 1 and n_components.

n_obs_component : Number of valid observations used for this component (short)

Number of valid observations used for this component_id.

component_flag : Component object flag (byte)

This flag provides information about the processing or scientific quality of the results of the GravLens chain on the component level. The flag checks two conditions:

1. 1.

   Whether ra_std_component $>$ 100 mas or dec_std_component $>$ 100 mas.

2. 2.

   Whether g_mag_std_component $>$ 0.4 mag.

The flag then is coded in the following way:

• •

  0 when none of the conditions above are met.

• •

  1 when the first condition is met but not the second.

• •

  10 when the second condition is met but not the first.

• •

  11 when both conditions are met.

ra_component : Mean right ascension of the component (double, Angle[deg])

The mean right ascension of the cluster of observations associated with this component within a fixed radius. The individual right ascensions as decoded from the transit_ids are stored in lens_observations.

ra_std_component : Standard deviation of the right ascension of the component (float, Angle[mas])

The standard deviation of right ascension measurements (multiplied by cos (dec_std_component)) for the cluster of observations associated with this component within a fixed radius. The individual right ascensions as decoded from the transit_ids are stored in lens_observations.

dec_component : Mean declination of the clusters of measurements (double, Angle[deg])

The mean declination of the cluster of observations associated with this component within a fixed radius. The individual declinations as decoded from the transit_ids are stored in lens_observations.

dec_std_component : Standard deviation of the declination measurements (float, Angle[mas])

The standard deviation of declination measurements for the cluster of observations associated with this component within a fixed radius. The individual declinations as decoded from the transit identifiers are stored in lens_observations.

g_flux_component : Mean G flux of the component (double, Flux[e${}^{-}$ s${}^{-1}$])

Mean G-band flux value for all observations belonging to this component. Note that this value may be missing in some cases.

g_flux_component_error : Uncertainty of the mean flux value for this component (float, Flux[e${}^{-}$ s${}^{-1}$])

Uncertainty of the mean G-band flux value for this component. Note that this value may be missing in some cases.

g_mag_component : Mean onboard G magnitude of the component (float, Magnitude[mag])

Mean VPU onboard G-band magnitude for the observations belonging to this component.

g_mag_std_component : Standard deviation of the onboard G magnitude of the component (float, Magnitude[mag])

Standard deviation of the VPU onboard G-band magnitudes for the observations belonging to this component.