Table information for 'gaia.edr3lite'

General

Table Description: This is a “light” version of the full Gaia eDR3 gaia_source table, containing the original astrometric and photmetric columns with just enough additional information to let careful researchers notice when data is becomes uncertain and the full error model should be consulted. The full eDR3 is available from numerous places in the VO (in particular from the TAP services ivo://uni-heidelberg.de/gaia/tap and ivo://esavo/gaia/tap).

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

Resource Description:

This is gaia_source from the Gaia early Data Release 3, stripped to just enough columns to enable basic science (but therefore a bit faster and simpler to deal with than the full gaia_source table).

Note that on this server, there is also The gedr3dist.main, which gives distances computed by Bailer-Jones et al. Use these in preference to working with the raw parallaxes.

This server also carries the gedr3mock schema containing a simulation of gaia_source based on a state-of-the-art galaxy model, computed by Rybizki et al.

For a list of all services and tables belonging to this table's resource, see Information on resource 'Selections from Gaia early Data Release 3 (eDR3)'

Citing this table

@MISC{vo:gaia_edr3lite,
  year=2020,
  title={Gaia eDR3 source catalogue "light"},
  author={{GAIA} Collaboration},
  url={http://dc.zah.uni-heidelberg.de/tableinfo/gaia.edr3lite},
  howpublished={{VO} resource provided by the {GAVO} Data Center}
}

Columns

Sorted alphabetically. [Sort by DB column index]

Columns that are parts of indices are marked like this.

VOResource

VO nerds may sometimes need VOResource XML for this table.

Notes

• 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.

• 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 eDR3 data in a paper, please take note of ESAC's guide on how to acknowledge and cite it.