Information on Service 'Gaia eDR3 Lite Distances Subset Cone Search'

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This service returns the most important Gaia eDR3 gaia_source columns together with robust geometric and photogeometric distances for the ~1.47 billion objects in Bailer-Jones et al's distance catalogue.

For a list of all services and tables belonging to this service's resource, see Information on resource 'Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3 (eDR3)'

Overview

You can access this service using:

This service is published as follows:

local means it is listed on our front page, ivo_managed means it has a record in the VO registry.

Other services provided on the underlying data include:

Spatial Coverage

Input Fields

The following fields are available to provide input to the service (with some renderers, some of these fields may be unavailable):

NameTable Head DescriptionUnitUCD
DEC Delta (ICRS) Declination (ICRS decimal) deg pos.eq.dec
hscs_pos Position/Name Coordinates (as h m s, d m s or decimal degrees), or SIMBAD-resolvable object N/A N/A
hscs_sr Search radius Search radius in arcminutes N/A N/A
MAXREC Match limit Maximum number of records returned. Pass 0 to retrieve service parameters. N/A N/A
r_med_geo Dist The median of the geometric distance posterior. The geometric distance estimate. pc pos.distance
r_med_photogeo Dist The median of the photogeometric distance posterior. The photogeometric distance estimate. pc pos.distance
RA Alpha (ICRS) Right Ascension (ICRS decimal) deg pos.eq.ra
RESPONSEFORMAT Output Format File format requested for output. N/A meta.code.mime
source_id Source Id Gaia eDR3 unique source identifier. Note that this *cannot* be matched against the DR1 or DR2 source_ids. N/A meta.id;meta.main
SR Search Radius Search radius deg N/A
VERB Verbosity Exhaustiveness of column selection. VERB=1 only returns the most important columns, VERB=2 selects the columns deemed useful to the average user, VERB=3 returns a table with all available columns. N/A N/A

Default Output Fields

The following fields are contained in the output by default. More fields may be available for selection; these would be given below in the VOTable output fields.

NameTable Head DescriptionUnitUCD
_r Dist. Distance to cone center deg pos.distance
astrometric_excess_noise ε_i This is the excess noise of the source, measuring the disagreement, expressed as an angle, between the observations of a source and the best-fitting standard astrometric model (using five astrometric parameters). A value of 0 signifies a well-behaved source, a positive value signifies that the residuals are larger than expected. mas stat.fit.goodness
astrometric_params_solved PS This is a binary code indicating which astrometric parameters were estimated for the source. A set bit means the parameter was estimated. The least-significant bit represents α, the next bits δ, parallax, PM(RA) and PM(De). For Gaia DR2 the only relevant values are 31 (all five parameters solved) and 3 (only positions). N/A meta.code
dec Dec (ICRS) Barycentric Declination in ICRS at epoch J2016.0 deg pos.eq.dec;meta.main
dec_error Err. Dec Standard error of dec mas stat.error;pos.eq.dec
dr2_radial_velocity RV Spectroscopic radial velocity in the solar barycentric reference frame taken from DR2. The radial velocity provided is the median value of the radial velocity measurements at all epochs. km/s spect.dopplerVeloc
dr2_radial_velocity_error Err. RV The radial velocity error is the error on the median to which a constant noise floor of 0.11 km/s has been added in quadrature to take into account the calibration contribution. Again, this is just taken over from DR2. km/s stat.error;spect.dopplerVeloc
flag Flags Additional information on the solution. Do not use for filtering (see table note in the reference URL). Note f N/A meta.code
parallax Parallax Absolute barycentric stellar parallax of the source at the reference epoch J2016.0. If looking for a distance, consider joining with gedr3dist.main and using the distances from there. mas pos.parallax
parallax_error Parallax_error Standard error of parallax mas stat.error;pos.parallax
phot_bp_mean_flux_over_error SNR BP Integrated mean BP flux divided by its error. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry. Note e N/A stat.snr;phot.flux;em.opt.B
phot_bp_mean_mag Mag BP Mean magnitude in the integrated BP band. This is computed from the BP-band mean flux applying the magnitude zero-point in the Vega scale. To obtain error estimates, see phot_bp_mean_flux_over_error. mag phot.mag;em.opt.B
phot_bp_rp_excess_factor BP/RP excess BP/RP excess factor estimated from the comparison of the sum of integrated BP and RP fluxes with respect to the flux in the G band. This measures the excess of flux in the BP and RP integrated photometry with respect to the G band. This excess is believed to be caused by background and contamination issues affecting the BP and RP data. Therefore a large value of this factor for a given source indicates systematic errors in the BP and RP photometry. N/A stat.fit.goodness
phot_g_mean_flux_over_error SNR G Integrated mean G flux divided by its error. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry. Note e s**-1 stat.snr;phot.flux;em.opt;stat.mean
phot_g_mean_mag m_G Mean magnitude in the G band. This is computed from the G-band mean flux applying the magnitude zero-point in the Vega scale. To obtain error estimates, see phot_g_mean_flux_over_error. mag phot.mag;em.opt;stat.mean
phot_rp_mean_flux_over_error SNR RP Integrated mean RP flux divided by its error. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry. Note e N/A stat.snr;phot.flux;em.opt.R
phot_rp_mean_mag Mag RP Mean magnitude in the integrated RP band. This is computed from the RP-band mean flux applying the magnitude zero-point in the Vega scale. To obtain error estimates, see phot_rp_mean_flux_over_error. mag phot.mag;em.opt.R
pmdec µ(Dec) Proper motion in declination at J2016.0. mas/yr pos.pm;pos.eq.dec
pmdec_error Err. PM(Dec) Standard error of pmdec mas/yr stat.error;pos.pm;pos.eq.dec
pmra µ(RA) Proper motion in right ascension of the source in ICRS at J2016.0. This is the tangent plane projection of the proper motion vector in the direction of increasing right ascension. mas/yr pos.pm;pos.eq.ra
pmra_error Err. PM(RA) Standard error of pmra mas/yr stat.error;pos.pm;pos.eq.ra
pseudocolour P.-colour Effective wavenumber of the source estimated in the final astrometric processing. The pseudocolour is the astrometrically estimated effective wavenumber of the photon flux distribution in the astrometric (G) band, estimated from the chromatic displacements of image centroids. The field is empty when chromaticity was instead taken into account using the photometrically determined ν_eff given in the field nu_eff_used_in_astrometry. um**-1 em.wavenumber;phot.color
r_hi_geo Dist. High The 84th percentile of the geometric distance posterior. The upper 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.max
r_hi_photogeo P. Dist. High The 84th percentile of the photogeometric distance posterior. The upper 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.max
r_lo_geo Dist. Low The 16th percentile of the geometric distance posterior. The lower 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.min
r_lo_photogeo P. Dist. Low The 16th percentile of the photogeometric distance posterior. The lower 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.min
r_med_geo Dist The median of the geometric distance posterior. The geometric distance estimate. Note d pc pos.distance
r_med_photogeo Dist The median of the photogeometric distance posterior. The photogeometric distance estimate. Note d pc pos.distance
ra RA (ICRS) Barycentric Right Ascension in ICRS at epoch J2016.0 deg pos.eq.ra;meta.main
ra_error Err. RA Standard error of ra (with cos δ applied). mas stat.error;pos.eq.ra
random_index Random Random index that can be used to deterministically select subsets N/A meta.code
ruwe RUWE Renormalized Unit Weight Error; this is a revised measure for the overall consistency of the solution as defined by GAIA-C3-TN-LU-LL-124-01. A suggested cut on this is RUWE <1.40) See the note for details. Note ruwe N/A stat.weight
source_id Source Id Gaia eDR3 unique source identifier. Note that this *cannot* be matched against the DR1 or DR2 source_ids. Note id N/A meta.id;meta.main

VOTable Output Fields

The following fields are available in VOTable output. The verbosity level is a number intended to represent the relative importance of the field on a scale of 1 to 30. The services take a VERB argument. A field is included in the output if their verbosity level is less or equal VERB*10.

NameTable Head DescriptionUnitUCD Verb. Level
source_id Source Id Gaia eDR3 unique source identifier. Note that this *cannot* be matched against the DR1 or DR2 source_ids. Note id N/A meta.id;meta.main 1
ra RA (ICRS) Barycentric Right Ascension in ICRS at epoch J2016.0 deg pos.eq.ra;meta.main 1
dec Dec (ICRS) Barycentric Declination in ICRS at epoch J2016.0 deg pos.eq.dec;meta.main 1
pmra µ(RA) Proper motion in right ascension of the source in ICRS at J2016.0. This is the tangent plane projection of the proper motion vector in the direction of increasing right ascension. mas/yr pos.pm;pos.eq.ra 1
pmdec µ(Dec) Proper motion in declination at J2016.0. mas/yr pos.pm;pos.eq.dec 1
parallax Parallax Absolute barycentric stellar parallax of the source at the reference epoch J2016.0. If looking for a distance, consider joining with gedr3dist.main and using the distances from there. mas pos.parallax 1
phot_g_mean_mag m_G Mean magnitude in the G band. This is computed from the G-band mean flux applying the magnitude zero-point in the Vega scale. To obtain error estimates, see phot_g_mean_flux_over_error. mag phot.mag;em.opt;stat.mean 1
phot_rp_mean_mag Mag RP Mean magnitude in the integrated RP band. This is computed from the RP-band mean flux applying the magnitude zero-point in the Vega scale. To obtain error estimates, see phot_rp_mean_flux_over_error. mag phot.mag;em.opt.R 1
phot_bp_mean_mag Mag BP Mean magnitude in the integrated BP band. This is computed from the BP-band mean flux applying the magnitude zero-point in the Vega scale. To obtain error estimates, see phot_bp_mean_flux_over_error. mag phot.mag;em.opt.B 1
dr2_radial_velocity RV Spectroscopic radial velocity in the solar barycentric reference frame taken from DR2. The radial velocity provided is the median value of the radial velocity measurements at all epochs. km/s spect.dopplerVeloc 1
r_med_geo Dist The median of the geometric distance posterior. The geometric distance estimate. Note d pc pos.distance 1
r_med_photogeo Dist The median of the photogeometric distance posterior. The photogeometric distance estimate. Note d pc pos.distance 1
ruwe RUWE Renormalized Unit Weight Error; this is a revised measure for the overall consistency of the solution as defined by GAIA-C3-TN-LU-LL-124-01. A suggested cut on this is RUWE <1.40) See the note for details. Note ruwe N/A stat.weight 5
r_lo_geo Dist. Low The 16th percentile of the geometric distance posterior. The lower 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.min 5
r_hi_geo Dist. High The 84th percentile of the geometric distance posterior. The upper 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.max 5
r_lo_photogeo P. Dist. Low The 16th percentile of the photogeometric distance posterior. The lower 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.min 5
r_hi_photogeo P. Dist. High The 84th percentile of the photogeometric distance posterior. The upper 1-sigma-like bound on the confidence interval. Note d pc pos.distance;stat.max 5
_r Dist. Distance to cone center deg pos.distance 10
astrometric_excess_noise ε_i This is the excess noise of the source, measuring the disagreement, expressed as an angle, between the observations of a source and the best-fitting standard astrometric model (using five astrometric parameters). A value of 0 signifies a well-behaved source, a positive value signifies that the residuals are larger than expected. mas stat.fit.goodness 15
pseudocolour P.-colour Effective wavenumber of the source estimated in the final astrometric processing. The pseudocolour is the astrometrically estimated effective wavenumber of the photon flux distribution in the astrometric (G) band, estimated from the chromatic displacements of image centroids. The field is empty when chromaticity was instead taken into account using the photometrically determined ν_eff given in the field nu_eff_used_in_astrometry. um**-1 em.wavenumber;phot.color 15
flag Flags Additional information on the solution. Do not use for filtering (see table note in the reference URL). Note f N/A meta.code 15
ra_error Err. RA Standard error of ra (with cos δ applied). mas stat.error;pos.eq.ra 20
dec_error Err. Dec Standard error of dec mas stat.error;pos.eq.dec 20
pmra_error Err. PM(RA) Standard error of pmra mas/yr stat.error;pos.pm;pos.eq.ra 20
pmdec_error Err. PM(Dec) Standard error of pmdec mas/yr stat.error;pos.pm;pos.eq.dec 20
parallax_error Parallax_error Standard error of parallax mas stat.error;pos.parallax 20
phot_g_mean_flux_over_error SNR G Integrated mean G flux divided by its error. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry. Note e s**-1 stat.snr;phot.flux;em.opt;stat.mean 20
phot_rp_mean_flux_over_error SNR RP Integrated mean RP flux divided by its error. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry. Note e N/A stat.snr;phot.flux;em.opt.R 20
phot_bp_mean_flux_over_error SNR BP Integrated mean BP flux divided by its error. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry. Note e N/A stat.snr;phot.flux;em.opt.B 20
phot_bp_rp_excess_factor BP/RP excess BP/RP excess factor estimated from the comparison of the sum of integrated BP and RP fluxes with respect to the flux in the G band. This measures the excess of flux in the BP and RP integrated photometry with respect to the G band. This excess is believed to be caused by background and contamination issues affecting the BP and RP data. Therefore a large value of this factor for a given source indicates systematic errors in the BP and RP photometry. N/A stat.fit.goodness 20
dr2_radial_velocity_error Err. RV The radial velocity error is the error on the median to which a constant noise floor of 0.11 km/s has been added in quadrature to take into account the calibration contribution. Again, this is just taken over from DR2. km/s stat.error;spect.dopplerVeloc 20
astrometric_params_solved PS This is a binary code indicating which astrometric parameters were estimated for the source. A set bit means the parameter was estimated. The least-significant bit represents α, the next bits δ, parallax, PM(RA) and PM(De). For Gaia DR2 the only relevant values are 31 (all five parameters solved) and 3 (only positions). N/A meta.code 20
random_index Random Random index that can be used to deterministically select subsets N/A meta.code 20
pseudocolour_error Err. PC Standard error of the pseudocolour. um**-1 stat.error;em.wavenumber;phot.color 25
visibility_periods_used #VP Number of visibility periods (groups of observations at least 4 days apart) used in the astrometric solution. A small value (less than 10) indicates that the calculated parallax could be more vulnerable to error not reflected in the formal uncertainties. N/A meta.number;obs 25

VOResource XML (that's something exclusively for VO nerds)

Note d

For each source we compute two posterior probability distributions over distance: a geometric one and a photogeometric one. “Geometric” means only parallax and the parallax uncertainty were used. “Photogeometric” means the G magnitude and the BP-RP colour were used as well. For each of these posterior distributions we estimate and provide three quantiles: 0.158655 (“Lo“), 0.5 (“Med”), and 0.841345 (“Hi”).

“Med” is the median of the distribution, and should be taken as the distance estimate itself. “Lo” and “Hi” define the lower and upper ends of the equal-tailed 68% (actually 68.269%) confidence interval on this estimate. If the posterior were Gaussian, then (r_hi_geo-r_lo_geo)/2 would be the 1-σ Gaussian uncertainty of the geometric distance (and similarly for the photogeometric distance). However, we stress that these confidence bounds are asymmetric, sometimes significantly so.

The distance estimates are predicated on the assumption that the source is a single star in our Galaxy. Estimates are provided whereever possible for sources that have the required input data, independent of any other knowledge on the nature of that source (e.g. being a binary star or quasar).

Note e

As long as the SNR is larger than 10 or so, 1.09*mag/snr is a reasonable approximation for an roughly symmetric magnitude error. For smaller SNR, the error distribution of the magnitude becomes very asymmetric and highly non-Gaussian.

Note f

The flag is normally a string with 5 decimal digits, ABBCC, the meaning of which is explained below. In some cases it can be "99", as also explained below.

This flag field is for information. It is not recommended to use this to filter out sources. Users may want to filter on the size of the distance confidence interval or on quality fields in the EDR3 gaia_source catalogue, such as ruwe, visibility_periods_used, or parallax_over_error. See the accompanying paper for more information.

A:
0:source does not have a G magnitude
1:source has G <= G_lim for that HEALpixel
2:source has G > G_lim for that HEALpixel
B:

The first (left-most) digit refers to the geometric posterior, the second to the photogeometric posterior. It indicates whether we have a low p-value (<1e-3) in the Hartigan Dip test (null hypothesis that posterior is unimodal, so small p suggests evidence against this). Two-digit integer. Each digit can be:

0:not set, so assume unimodal hypothesis okay (or if test is not done or gives no answer)
1:set, so possibly multimodal.

For instance, 10 means geo possibly multimodal, photgeo probably unimodal Moreover, the computed confidence interval often spans any multimodality, so generally speaking sources do not need to be excluded just because of evidence of multimodality from this test. This flag refers to the posterior as sampled by the MCMC rather than the true posterior.

C:

QG models used to compute the photogeometric posterior. Two digit integer. Each digit can be:

0:NULL
1:one-component Gaussian model
2:two-component Gaussian model
3:smoothing spline

The first (left-most) digit refers to the lower (bluer) model, the second to the upper (redder) model. E.g. 13 means the lower one was a one-component Gaussian and the upper one was was spline.

There is also a special setting of this flag:

99:

data (G or BP-RP) were missing (so no photogeo distance could be computed)

Note id

For the contents of Gaia eDR3, the source ID consists of a 64-bit integer, least significant bit = 1 and most significant bit = 64, comprising:

  • a HEALPix index number (sky pixel) in bits 36 - 63; by definition the
    smallest HEALPix index number is zero.
  • a 2-bit Data Processing Centre code in bits 34 - 35; for example
    MOD(source_id / 4294967296, 8) can be used to distinguish between sources initialised via the Initial Gaia Source List by the Torino DPC (code = 0) and sources otherwise detected and assigned by Gaia observations (code > 0)
  • a 25-bit plus 7 bit sequence number within the HEALPix pixel in bits 1
    to 32 split into:
    • a 25 bit running number in bits 8 x 32; the running numbers are
      defined to be positive, i.e. never zero (except in the case of forced empty windows)
    • a 7-bit component number in bits 1 x 7 one spare bit in bit 33

This means that the HEALpix index level 12 of a given source is contained in the most significant bits. HEALpix index of 12 and lower levels can thus be retrieved as follows:

  • HEALpix level 12 = source_id / 34359738368
  • HEALpix level 11 = source_id / 137438953472
  • HEALpix level 10 = source_id / 549755813888
  • HEALpix level n = source_id / 2^35 * 4^(12 - level).
Note ruwe

The Renormalized Unit Weight Error (RUWE) is defined in L. Lindegren: Re-normalising the astrometric chi-square in Gaia DR2 (Gaia tech note GAIA-C3-TN-LU-LL-124-01). This is essentially the astrometric_chi2 from the DR2 release, but corrected for its strong dependency on magnitude and colour. For quality cuts, this is the recommended quantity to use. Lindegren suggests using RUWE<1.4 as a quality cut for “good” solutions based on the shape of the distribution.

The values given here were calculated independently of DPAC and do not use interpolation on the grids provided by Lindegren et al. Thus, minor differences from the “official” RUWE values are expected. As Lindegren et al point out, such differences should not matter in science applications, though.