Table information for 'gaia.edr3lite'

General

Table Description: This is a “light” version of the full Gaia DR3 gaia_source table. It is just a view copying gaia.dr3lite, which should preferentially be used in new queries. This table is being kept around in order to keep legacy queries from breaking unnecessarily. However, it is actually DR3 data rather than eDR3. The minute differences did not seem to warrant keeping two copies of the relatively massive data around.

This table is available for ADQL queries and through the TAP endpoint.

Resource Description:

This schema contains data re-published from the official Gaia mirrors (such as ivo://uni-heidelberg.de/gaia/tap) either to support combining its data with local tables (the various Xlite tables) or to make the data more accessible to VO clients (e.g., epoch fluxes).

For a list of all services and tables belonging to this table's resource, see Information on resource 'Selections from Gaia Data Release 3 (DR3)'

Citing this table

To cite the table as such, we suggest the following BibTeX entry:

@MISC{vo:gaia_edr3lite,
  year=2020,
  title={Gaia eDR3 source catalogue "light"},
  author={{GAIA} Collaboration},
  url={http://data.xao.ac.cn/tableinfo/gaia.edr3lite},
  howpublished={{VO} resource provided by the {XAO} Data Center}
}

Columns

Sorted by DB column index. [Sort alphabetically]

Name	Table Head	Description	Unit	UCD
source_id	Source Id	Gaia DR3 unique source identifier. Note that this cannot be matched against the DR1 or DR2 source_ids. [Note id]	N/A	meta.id;meta.main
ra	RA (ICRS)	Barycentric Right Ascension in ICRS at epoch J2016.0	deg	pos.eq.ra;meta.main
dec	Dec (ICRS)	Barycentric Declination in ICRS at epoch J2016.0	deg	pos.eq.dec;meta.main
ra_error	Err. RA	Standard error of ra (with cos δ applied).	mas	stat.error;pos.eq.ra
dec_error	Err. Dec	Standard error of dec	mas	stat.error;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 (i.e., multiplied by cos(δ)) of the proper motion vector in the direction of increasing right ascension.	mas/yr	pos.pm;pos.eq.ra
pmdec	µ(Dec)	Proper motion in declination at J2016.0.	mas/yr	pos.pm;pos.eq.dec
pmra_error	Err. PM(RA)	Standard error of pmra	mas/yr	stat.error;pos.pm;pos.eq.ra
pmdec_error	Err. PM(Dec)	Standard error of pmdec	mas/yr	stat.error;pos.pm;pos.eq.dec
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_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_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]	N/A	stat.snr;phot.flux;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
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
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
radial_velocity	RV	Spectroscopic radial velocity in the solar barycentric reference frame. For stars brighter than about 12 mag, this is the median of all single-epoch measurements. For fainter stars, RV estimation is from a co-added spectrum.	km/s	spect.dopplerVeloc.opt;em.opt.I
radial_velocity_error	Err. RV	Error in radial_velocity; this is the error of the median for bright stars. For faint stars, it is derived from the cross-correlation function.	km/s	stat.error;spect.dopplerVeloc
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
pseudocolour_error	Err. PC	Standard error of the pseudocolour.	um**-1	stat.error;em.wavenumber;phot.color
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
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
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

Columns that are parts of indices are marked like this.

Other

The following services may use the data contained in this table:

Gaia DR3 Lite Cone Search

VOResource

VO nerds may sometimes need VOResource XML for this table.

Notes

Note id
For the contents of Gaia DR3, 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 3-bit Data Processing Centre code in bits 33 - 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 - 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 - 7
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.
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.

Copyright and such:

If you use public Gaia DR3 data in a paper, please take note of ESAC's guide on how to acknowledge and cite it.

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