A Gaia DR2 mock stellar catalogivo://org.gavo.dc/gdr2mock/q/maindoi:10.21938/SYx.JVejuu66uzDiLcfRlAThe GAVO DC teamRybizki, J.Demleitner, M.Fouesneau, M.Bailer-Jones, C.Rix, H.-W.Andrae, R.2019-06-11T13:12:112018-07-242018-05-172018-04-25GAVO Data Center TeamMönchhofstrasse 12-14, D-69120 Heidelberggavo@ari.uni-heidelberg.de++49 6221 54 1837GaiaSelection functionMilky WayA synthetic Milky Way catalog mimicking GDR2 in stellar content and
data model.OpticalInfraredgdr2mockA Gaia DR2 mock stellar catalog This catalogue is a simulation of the Gaia DR2 stellar content using
Galaxia (a tool to sample stars from a Besancon-like Milky Way model),
3d dust extinction maps and the latest PARSEC Isochrones. It is
mimicking the Gaia DR2 data model and an apparent magnitude limit of
g=20,7. Extinctions and photometry in different bands have also been
included in a supplementary table as well as uncertainty estimates
using a scaled nominal error model.gdr2mock.mainA synthetic Milky Way catalog mimicking GDR2 in stellar content and
data model.source_idHealpix number using Nside = 4096 with the nested scheme on equatorial coordinates times 2^35. The last digits of the source_id are reserved for a running number that serves as a unique identifier per HEALPix cell. This is formed in accordance with Gaia's source_id definition, but of course mock objects have no relation to any Gaia objects that may have an identical source_id.meta.id;meta.mainlongindexedraBarycentric Right Ascension in ICRS at ref_epochdegpos.eq.ra;meta.maindoubleindexednullabledecBarycentric Declination in ICRS at ref_epochdegpos.eq.dec;meta.maindoubleindexednullablera_errorStandard error of ra (with cos δ applied).masstat.error;pos.eq.rafloatnullabledec_errorStandard error of decmasstat.error;pos.eq.decfloatnullablepmraProper motion in right ascension of the source in ICRS at ref_epoch. This is the projection of the proper motion vector in the direction of increasing right ascension.mas/yrpos.pm;pos.eq.rafloatindexednullablepmdecProper motion in declination at ref_epoch.mas/yrpos.pm;pos.eq.decfloatindexednullablepmra_errorStandard error of pmramas/yrstat.error;pos.pm;pos.eq.rafloatnullablepmdec_errorStandard error of pmdecmas/yrstat.error;pos.pm;pos.eq.decfloatnullableparallaxAbsolute barycentric stellar parallax of the source at the reference epoch ref_epoch. If looking for a distance, consider joining with gdr2dist.main and using the distances from there.maspos.parallaxfloatnullableparallax_errorStandard error of parallaxmasstat.error;pos.parallaxfloatnullablephot_g_mean_magMean magnitude in the G band. This is computed from the G-band mean flux applying the magnitude zero-point in the Vega scale.magphot.mag;em.opt;stat.meanfloatindexednullablephot_g_mean_fluxG-band mean flux as electrons per second.s**-1phot.flux;em.opt;stat.meandoublenullablephot_g_mean_flux_errorError on phot_g_mean_fluxs**-1stat.error;phot.flux;em.opt;stat.meanfloatnullablephot_rp_mean_fluxMean flux in the integrated RP band.s**-1phot.flux;em.opt.Rdoublenullablephot_rp_mean_flux_errorError in the mean flux in the integrated RP band. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry.s**-1stat.error;phot.flux;em.opt.Rfloatnullablephot_rp_mean_magMean magnitude in the integrated RP band. This is computed from the RP-band mean flux applying the magnitude zero-point in the Vega scale. No error is provided for this quantity as the error distribution is only symmetric in flux space. For errors small compared to the flux (less than 10%, say), the magnitude error is well approximated by 1.09*flux/flux_err.magphot.mag;em.opt.Rfloatindexednullablephot_bp_mean_fluxMean flux in the integrated BP band.s**-1phot.flux;em.opt.Bdoublenullablephot_bp_mean_flux_errorError in the mean flux in the integrated BP band. Errors are computed from the dispersion about the weighted mean of the input calibrated photometry.s**-1stat.error;phot.flux;em.opt.Bfloatnullablephot_bp_mean_magMean magnitude in the integrated BP band. This is computed from the BP-band mean flux applying the magnitude zero-point in the Vega scale. No error is provided for this quantity as the error distribution is only symmetric in flux space. For errors small compared to the flux (less than 10%, say), the magnitude error is well approximated by 1.09*flux/flux_err.magphot.mag;em.opt.Bfloatindexednullablephot_bp_rp_excess_factorBP/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.stat.fit.goodnessfloatnullableradial_velocitySpectroscopic radial velocity in the solar barycentric reference frame. The radial velocity provided is the median value of the radial velocity measurements at all epochs. Warning: in the vicinity of bright stars, DR2 RVs can be grossly wrong. See arXiv:1901.10460 for details.km/sspect.dopplerVelocfloatnullableradial_velocity_errorThe 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.km/sstat.error;spect.dopplerVelocfloatnullableastrometric_gof_alGoodness-of-fit statistic of the astrometric solution for the source in the along-scan direction (you probably want to use RUWE instead of this).stat.fit.goodnessfloatnullableastrometric_params_solvedThis 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).meta.codefloatnullablerandom_indexRandom index that can be used to deterministically select subsetsmeta.codelongindexedlGalactic longitude (converted from ra, dec)degpos.galactic.londoubleindexednullablebGalactic latitude (converted from ra, dec)degpos.galactic.latdoubleindexednullablephot_g_n_obsNumber of observations contributing to G photometrymeta.numbershortnullablephot_variable_flagPhotometric variability flagmeta.code;src.varcharnullablephot_rp_n_obsNumber of observations (CCD transits) that contributed to the integrated RP mean flux and mean flux error.meta.number;obs;phot.mag;em.opt.Rshortphot_bp_n_obsNumber of observations (CCD transits) that contributed to the integrated BP mean flux and mean flux error.meta.number;obs;phot.mag;em.opt.Bshortbp_rpBP-RP colormagphot.color;em.opt.B;em.opt.Rfloatnullablebp_gBP-G colormagphot.color;em.opt.B;em.opt.Vfloatnullableg_rpG-RP colormagphot.color;em.opt.V;em.opt.Rfloatnullablephot_rvs_mean_magApproximate estimate for the RVS magnitude. This uses formulae (2) and (3) from 2018A&A...616A...1G. Outside of the range 0.1<BP-G<1.7 we use Eq. 3 (which means the value is probably fairly bogus).magphot.color;em.opt.Ifloatnullablerv_nb_transitsNumber of transits (epochs) used to compute radial velocity.stat.number;obs;spect.dopplerVelocshortref_epochReference epoch to which the astrometic source parameters are referred, expressed as a Julian Year in TCB.yrmeta.ref;time.epochdoublenullableastrometric_delta_qHipparcos/Gaia data discrepancy (Hipparcos subset of TGAS only)stat.valuefloatnullableastrometric_excess_noiseExcess noise of the sourcemasstat.valuefloatnullableastrometric_excess_noise_sigSignificance of excess noisestat.valuefloatnullableastrometric_n_obs_acTotal number of observations ACmeta.numbershortastrometric_n_obs_alTotal number of observations ALmeta.numbershortastrometric_n_bad_obs_acNumber of bad observations ACmeta.numbershortastrometric_n_bad_obs_alNumber of bad observations ALmeta.numbershortastrometric_n_good_obs_acNumber of good observations ACmeta.numbershortastrometric_n_good_obs_alNumber of good observations ALmeta.numbershortastrometric_chi2_alAstrometric goodness-of-fit (χ²) in the AL direction; χ² values were computed for the ‘good’ AL observations of the source, without taking into account the astrometric excess noise (if any) of the source. They do, however, take into account the attitude excess noise (if any) of each observation.stat.fit.chi2floatnullableastrometric_primary_flagOnly primary sources (for which this flag is True) contribute to the estimation of attitude, calibration, and global parameters. The estimation of source parameters is not affected by primariness.meta.codeshortastrometric_pseudo_colourColour of the source assumed in the final astrometric processing, given as he effective wavenumber of the photon flux distribution in the astrometric (G) band. The value given in this field was astrometrically determined in a preliminary solution, using the chromatic displacement of image centroids calibrated by means of the effective wavenumbers (ν_eff) of primary sources calculated from BP and RP magnitudes. The field is empty when no such determination was possible, in which case a default value of 1.6 1/µm was assumed.um**-1floatnullablemean_varpi_factor_alMean parallax factor in the AL direction, computed from all the good observations of the source processed in the astrometry. The value given in this field is typically in the range [−0.23, +0.32] (1st and 99th percentiles). A value outside this range indicates a distribution of observations that is unfavourable for the determination of the parallax, and the calculated parallax could then be more vulnerable to errors, e.g. from the calibration model, not reflected in the formal uncertainties.stat.fit.paramfloatnullablevisiblilty_periods_usedNumber of visibility periods used in Astrometric solution. A visibility period is a group of observations separated from other groups by a gap of at least 4 days.stat.number;obsshortastrometric_sigma5d_maxThe longest principal axis in the 5-dimensional error ellipsoid. This is useful for filtering out cases where one of the five parameters, or some linear combination of several parameters, is particularly ill-determined. It is measured in mas and computed as the square root of the largest singular value of the scaled 5 × 5 covariance matrix of the astrometric parameters.masstat.error;obs;stat.maxfloatnullablematched_observationsThe number of observations (detection transits) that have been matched to a given source during the last internal crossmatch revision.meta.numbershortastrometric_priors_usedType of prior used in in the astrometric solutionshortnullableastrometric_relegation_factorRelegation factor of the source calculated as per Eq. (118) in 2012A&A...538A..78L used for the primary selection process.arith.factorfloatnullableastrometric_weight_acMean astrometric weight of the sourcemas**-2stat.weight;stat.meanfloatnullableastrometric_weight_alMean astrometric weight of the sourcemas**-2stat.weight;stat.meanfloatnullableduplicated_sourceDuring data processing, this source happened to have been duplicated and one source only has been kept.shortra_dec_corrCorrelation between right ascension and declinationstat.correlationfloatnullablera_pmra_corrCorrelation between right ascension and proper motion in right ascensionstat.correlationfloatnullablera_pmdec_corrCorrelation between right ascension and proper motion in declinationstat.correlationfloatnullabledec_pmra_corrCorrelation between declination and proper motion in right ascensionstat.correlationfloatnullabledec_pmdec_corrCorrelation between declination and proper motion in declinationstat.correlationfloatnullablepmra_pmdec_corrCorrelation between proper motion in right ascension and proper motion in declinationstat.correlationfloatnullablera_parallax_corrCorrelation between right ascension and parallaxstat.correlationfloatnullabledec_parallax_corrCorrelation between declination and parallaxstat.correlationfloatnullableparallax_pmra_corrCorrelation between parallax and proper motion in right ascensionstat.correlationfloatnullableparallax_pmdec_corrCorrelation between parallax and proper motion in declinationstat.correlationfloatnullablescan_direction_mean_k1Mean position angle of scan directions across the sourcedegfloatnullablescan_direction_strength_k1Degree of concentration of scan directions across the sourcefloatnullablescan_direction_mean_k2Mean position angle of scan directions across the sourcedegfloatnullablescan_direction_strength_k2Degree of concentration of scan directions across the sourcefloatnullablescan_direction_mean_k3Mean position angle of scan directions across the sourcedegfloatnullablescan_direction_strength_k3Degree of concentration of scan directions across the sourcefloatnullablescan_direction_mean_k4Mean position angle of scan directions across the sourcedegfloatnullablescan_direction_strength_k4Degree of concentration of scan directions across the sourcefloatnullablepriam_flagsFlags describing the status of the astrophysical parameters Teff, A G and E[BP-RP] (i.e., those determined by Apsis-Priam). See the release documentation.meta.codelongnullableflame_flagsFlags describing the status of the astrophysical parameters radius and luminosity (i.e., those determined by Apsis-FLAME). See the release documentation.meta.codelongnullableteff_valEffective temperature of the starKphys.temperaturefloatnullableteff_percentile_lowerLower uncertainty bound of the effective temperature estimate from Apsis-Priam. This is the 16th percentile of its PDF.Kstat.min;phys.temperaturefloatnullableteff_percentile_upperUpper uncertainty bound of the effective temperature estimate from Apsis-Priam. This is the 84th percentile of its PDF.Kstat.max;phys.temperaturefloatnullablea_g_valLine-of-sight extinction in the G band, A_Gmagphys.absorptionfloatnullablea_g_percentile_lowerLower uncertainty bound of the line-of-sight extinction in the G-band estimate from Apsis-Priam. This is the 16th percentile of its PDF.magstat.min;phys.absorptionfloatnullablea_g_percentile_upperUpper uncertainty bound of the line-of-sight extinction in the G-band estimate from Apsis-Priam. This is the 84th percentile of its PDF.magstat.max;phys.absorptionfloatnullablee_bp_min_rp_valLine-of-sight reddening E(BP-RP)magphys.absorptionfloatnullablee_bp_min_rp_percentile_lowerLower uncertainty bound of the line-of-sight reddening E(BP-RP) estimate from Apsis-Priam. This is the 16th percentile of its PDF.magstat.min;phys.absorptionfloatnullablee_bp_min_rp_percentile_upperUpper uncertainty bound of the line-of-sight reddening E(BP-RP) estimate from Apsis-Priam. This is the 84th percentile of its PDF.magstat.max;phys.absorptionfloatnullableradius_valStellar radius in solar radiisolRadphys.size.radiusfloatnullableradius_percentile_lowerLower uncertainty bound of the radius estimate from Apsis-FLAME. This is the 16th percentile of its PDF.solRadstat.min;phys.size.radiusfloatnullableradius_percentile_upperUpper uncertainty bound of the radius estimate from Apsis-FLAME. This is the 84th percentile of its PDF.solRadstat.max;phys.size.radiusfloatnullablelum_valStellar luminosity in solar luminosities.solLumphys.luminosityfloatnullablelum_percentile_lowerLower uncertainty bound of the luminosity estimate from Apsis-FLAME. This is the 16th percentile of its PDF.solLumstat.min;phys.luminosityfloatnullablelum_percentile_upperUpper uncertainty bound of the luminosity estimate from Apsis-FLAME. This is the 84th percentile of its PDF.solLumstat.max;phys.luminosityfloatnullablefehFe/H as log10 of solar ratio ('dex')phys.abund.Fefloatnullablea0Monochromatic extinction at lambda = 547.7nmmagphys.absorptionfloatnullablemassInitial mass of the starsolMassphys.massfloatnullableageAge of the starGyrtime.agefloatnullableloggLogarithm of surface gravity.log(cm/(s**2))phys.gravityfloatnullablenobsNominal number of observations, scaled to the shorter time base of GDR2 (a function with ecliptic latitude).meta.number;obsfloatnullableindex_parsecForeign key into the photometry/extinction table.meta.id.crossint