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gaia data release 3 documentation

20.14 Performance verification

20.14.7 gold_sample_ucd

The table contains the bolometric luminosities and radii in solar units for a subset of ultracool dwarfs from the Gaia DR3 catalogue, as well as some intermediate quantities used in the selection of sources and in the derivation of the luminosities and radii.
For more details please refer to Gaia Collaboration et al. (2023c).

Columns description:

source_id : Unique source identifier (unique within a particular Data Release) (long)

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

ftot_fobs : Correction factor applied to obtain the total SED flux (float)

Multiplicative factor used to scale the total observed flux to obtain the total SED flux. It is derived using the CIFIST 2011-2015 BT Settl models of solar metallicity and logg=5 and interpolating the ESP-UCD effective temperature in the BT Settl grid values.

lum : Bolometric luminosity in solar units (float, Luminosity[Solar Luminosity])

Bolometric luminosity of the UCD in solar units obtained by scaling the observed flux using ftot_fobs and using the Gaia measured parallax.

lum_uncertainty : Uncertainty in bolometric luminosity (float, Luminosity[Solar Luminosity])

Uncertainty in UCD bolometric luminosity calculated using a simple Taylor expansion and neglecting the correlations.

radius : Radius in solar unit (float, Length & Distance[Solar Radius])

Radius of the UCD derived using the Stefan-Boltzmann law, the UCD bolometric luminosity and the ESP-UCD effective temperature.

radius_uncertainty : Uncertainty in radius (float, Length & Distance[Solar Radius])

Uncertainty in the UCD radius calculated using a simple Taylor expansion and neglecting the correlations.

reduced_chi2 : Reduced chi-square of the SED fit (float)

Reduced χ2 of the Virtual Observatory SED Analyzer (VOSA) fit to the observed fluxes.