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J/ApJ/833/119       Distances of Gaia DR1 TGAS sources     (Astraatmadja+, 2016)

Estimating distances from parallaxes. III. Distances of two million stars in the Gaia DR1 catalogue. Astraatmadja T.L., Bailer-Jones C.A.L. <Astrophys. J., 833, 119 (2016)> =2016ApJ...833..119A
ADC_Keywords: Surveys ; Parallaxes, trigonometric ; Stars, distances Keywords: catalogs - methods: data analysis - methods: statistical - parallaxes - stars: distances - surveys Abstract: We infer distances and their asymmetric uncertainties for two million stars using the parallaxes published in the Gaia DR1 (GDR1) catalogue. We do this with two distance priors: A minimalist, isotropic prior assuming an exponentially decreasing space density with increasing distance, and an anisotropic prior derived from the observability of stars in a Milky Way model. We validate our results by comparing our distance estimates for 105 Cepheids which have more precise, independently estimated distances. For this sample we find that the Milky Way prior performs better (the RMS of the scaled residuals is 0.40) than the exponentially decreasing space density prior (RMS is 0.57), although for distances beyond 2kpc the Milky Way prior performs worse, with a bias in the scaled residuals of -0.36 (vs. -0.07 for the exponentially decreasing space density prior). We do not attempt to include the photometric data in GDR1 due to the lack of reliable colour information. Our distance catalogue is available at http://www.mpia.de/homes/calj/tgas_distances/main.html. These should only be used to give individual distances. Combining data or testing models should be done with the original parallaxes, and attention paid to correlated and systematic uncertainties. Description: This is a catalogue of distances and their asymmetric uncertainties inferred from the parallaxes published in the Gaia DR1 catalogue. Two priors are used: The exponentially decreasing space density and the Milky Way prior. For the exponentially decreasing space density prior, two scale lengths are used: 110pc and 1350pc. The former is based on a fitting of the true distance distribution of a subset of the GUMS catalogue (Robin et al., 2012, Cat. VI/137) which are limited to V<11. This is the magnitude at which Tycho-2 is 99% complete. The latter is based on the same procedure but limited to G=20.7, which is the expected limiting magnitude of Gaia. For the Milky Way prior, the parameters are described in the paper. We report the mode of the posterior PDF, the median, the 90% credible interval, and a standard deviation in distance which are calculated by scaling the 90% into 68.3%. The Cepheids data used for the validation of the results are included here as well. They are taken from Groenewegen (2013, Cat. J/A+A/550/A70) and cross-matched with Hipparcos and/or Tycho by making a Simbad query of each Cepheids and finding the corresponding Hipparcos and/or Tyho identifier. The distances are inferred either by neglecting the systematic uncertainties of 0.3mas (Gaia Collaboration et al., 2016, Cat. I/337) for reasons described in the paper, or by adding a systematic uncertainties of 0.3mas in quadrature with the random parallax uncertainties. We provide both results here. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file distall.dat 359 2057050 Distances and uncertainties of all TGAS sources, no systematics uncertainties included (tgasdistall_v01) distallw.dat 359 2057050 Distances and uncertainties of all TGAS sources, systematics uncertainties of 0.3mas included (tgasdistallwithsysv01.csv) distcep.dat 400 105 Distances and uncertainties of all TGAS sources containing Groenewenegen (2013, J/A+A/550/A70) Cepheids, no systematics uncertainties included (tgasdistcepheids_v01.csv) distcepw.dat 400 105 Distances and uncertainties of all TGAS sources containing Groenewenegen (2013, J/A+A/550/A70) Cepheids, systematics uncertainties of 0.3mas included (tgasdistcepheidswithsysv01.csv)
See also: I/337 : Gaia DR1 (Gaia Collaboration, 2016) J/A+A/550/A70 : Galactic & Magellanic Clouds Cepheids distances (Groenewegen 2013) Byte-by-byte Description of file: distall.dat distallw.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HIP ? Hipparcos identifier 8- 19 A12 --- Tycho2 Tycho 2 identifier 21- 39 I19 --- Source Gaia (I/337) source ID 41- 58 F18.14 deg GLON Galactic longitude at epoch J2015.0 60- 77 F18.14 deg GLAT Galactic latitude at epoch J2015.0 79- 96 F18.14 mas varpi Absolute barycentric stellar parallax of the source at epoch 2015.0 98-113 F16.14 mas e_varpi Standard error of parallax 115-120 F6.3 mag <Gmag> G-band mean magnitude 122-135 F14.9 pc rMoExp1 Mode distance of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 137-151 F15.9 pc r5Exp1 5th percentile of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 153-167 F15.9 pc r50Exp1 50th percentile (i.e. the median) of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 169-183 F15.9 pc r95Exp1 95th percentile of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 185-197 F13.9 pc sigmaRExp1 Distance standard error, using the exponentially decreasing space density prior with L=0.11kpc 199-213 F15.9 pc rMoExp2 Mode distance of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 215-229 F15.9 pc r5Exp2 5th percentile of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 231-245 F15.9 pc r50Exp2 50th percentile (i.e. the median) of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 247-261 F15.9 pc r95Exp2 95th percentile of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 263-276 F14.9 pc sigmaRExp2 Distance standard error, using the exponentially decreasing space density prior with L=1.35kpc 278-292 F15.9 pc rMoMW Mode distance of the posterior, using Milky Way Prior 294-309 F16.9 pc r5MW 5th percentile of the posterior, using Milky Way Prior 311-326 F16.9 pc r50MW 50th percentile (i.e. the median) of the posterior, using Milky Way Prior 328-343 F16.9 pc r95MW 95th percentile of the posterior, using Milky Way Prior 345-359 F15.9 pc sigmaRMW Distance standard error, using Milky Way Prior
Byte-by-byte Description of file: distcep.dat distcepw.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HIP ? Hipparcos identifier 8- 18 A11 --- Tycho2 Tycho 2 identifier 20- 38 I19 --- Source Gaia (I/337) source ID 40- 57 F18.14 deg GLON Galactic longitude at epoch J2015.0 59- 76 F18.14 deg GLAT Galactic latitude at epoch J2015.0 78- 94 F17.14 mas varpi Absolute barycentric stellar parallax of the source at epoch 2015.0 96-111 F16.14 mas e_varpi Standard error of parallax 113-118 F6.3 mag <Gmag> G-band mean magnitude 120-133 F14.9 pc rMoExp1 Mode distance of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 135-147 F13.9 pc r5Exp1 5th percentile of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 149-162 F14.9 pc r50Exp1 50th percentile (i.e. the median) of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 164-177 F14.9 pc r95Exp1 95th percentile of the posterior, using the exponentially decreasing space density prior with L=0.11kpc 179-191 F13.9 pc sigmaRExp1 Distance standard error, using the exponentially decreasing space density prior with L=0.11kpc 193-206 F14.9 pc rMoExp2 Mode distance of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 208-221 F14.9 pc r5Exp2 5th percentile of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 223-236 F14.9 pc r50Exp2 50th percentile (i.e. the median) of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 238-251 F14.9 pc r95Exp2 95th percentile of the posterior, using the exponentially decreasing space density prior with L=1.35kpc 253-266 F14.9 pc sigmaRExp2 Distance standard error, using the exponentially decreasing space density prior with L=1.35kpc 268-281 F14.9 pc rMoMW Mode distance of the posterior, using Milky Way Prior 283-296 F14.9 pc r5MW 5th percentile of the posterior, using Milky Way Prior 298-311 F14.9 pc r50MW 50th percentile (i.e. the median) of the posterior, using Milky Way Prior 313-326 F14.9 pc r95MW 95th percentile of the posterior, using Milky Way Prior 328-341 F14.9 pc sigmaRMW Distance standard error, using Milky Way Prior 343-351 A9 --- CepName Cepheid name 353-362 A10 --- HIPName Hipparcos identifier (HIP NNNNNN) 364-378 A15 --- TYC Tycho 2 identifier (TYC NNNN-NNNN-N) 380-386 F7.1 pc rCep Cepheid distance 388-393 F6.1 pc sigmaRCep1 Error in the fit on rCep 395-400 F6.1 pc sigmaRCep2 Error based on Monte-Carlo simulation on rCep
Acknowledgements: Tri L. Astraatmadja, tastraatmadja(at)carnegiescience.edu DTM, Carnegie Institution for Science References: Bailer-Jones, Paper I, 2015PASP..127..994B Astraatmadja & Bailer-Jones, Paper II 2016ApJ...832..137A
(End) Tri L. Astraatmadja [DTM, CIS], Patricia Vannier [CDS] 29-Sep-2016
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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