J/other/RAA/18.1ivo://CDS.VizieR/J/other/RAA/18.146doi:10.26093/cds/vizier/dx/bikbegCDSXu Y.Hou L.-G.Wu Y.-W.2026-02-10T20:07:30Z2019-10-02T09:33:41ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frmilky-way-galaxyastrophysical-masersradio-astronomyo-starsproper-motionsvisible-astronomytrigonometric-parallaxThe morphology and kinematics of the spiral structure of the Milky Way are long-standing problems in astrophysics. In this review we firstly summarize various methods with different tracers used to solve this puzzle. The astrometry of Galactic sources is gradually alleviating this difficult situation caused mainly by large distance uncertainties, as we can currently obtain accurate parallaxes (a few {mu}as) and proper motions (~1km/s) by using Very Long Baseline Interferometry (VLBI). On the other hand, the Gaia mission is providing the largest, uniform sample of parallaxes for O-type stars in the entire Milky Way. Based upon the VLBI maser and Gaia O-star parallax measurements, nearby spiral structures of the Perseus, Local, Sagittarius and Scutum Arms are determined in unprecedented detail. Meanwhile, we estimate fundamental Galactic parameters of the distance to the Galactic center, R_0_, to be 8.35+/-0.18kpc, and circular rotation speed at the Sun, {THETA}_0_, to be 240+/-10km/s. We found kinematic differences between O stars and interstellar masers: the O stars, on average, rotate faster, >8km/s than maser-traced high-mass star forming regions.2018RAA....18..146Xhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/other/RAA/18.146CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)J/A+A/616/L15 : Parallaxes and Proper Motions of OB stars (Xu+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/other/RAA/18.146https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/other/RAA/18.146http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/other/RAA/18.146https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/other/RAA/18.146https://vizier.iucaa.in/viz-bin/votable?-source=J/other/RAA/18.146http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/other/RAA/18.146GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/other/RAA/18.146/table2 (Parallaxes and proper motions of masers)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/other/RAA/18.146/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/other/RAA/18.146/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/other/RAA/18.146/table2?GETtext/xml+votable180.050000true287.555849.103570.005555555555555556Cone search capability for table J/other/RAA/18.146/table3 (Parallaxes and proper motions of O Stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/other/RAA/18.146/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/other/RAA/18.146/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/other/RAA/18.146/table3?GETtext/xml+votable180.050000true115.5803318-34.767864460.0055555555555555565/3661 3672 7278 7383 9333 9504 10553 6/1196 1293 1297 1470 1790 1956 2940 2973 3011 3035 3037 3051 3054 3057-3059 3061-3062 3066-3068 3231 3245 3247 3256 3262-3263 3272-3273 3283 3301 3307 3311-3312 3315 3337 3384 3585 3596 3600 3609 3615 3622 3648-3649 3653 3724 3754-3755 6891 12943 12973 13244 13281 13557 13999 14008 14063 14241 14247 14251 14253 14255 14258 14263 14280 14283 14299 14303 14309-14311 14314 14317 14328 14353-14355 14358-14359 14409 14456 14594 14604-14605 14607 14619 14621-14623 14625 14630-14633 14636 14640-14641 14643 14654-14655 14658 14670-14671 14674 14683 14692-14693 14695 14697-14698 14701 14704 14706 14712 14719 14740-14741 14743 14745 14793 14824 15369 15379 15429 15458 15473 15476 15486 15625 15631 15634 15656 15663 15670-15672 15676 15681-15683 15703 15745 15759 15808 20613 21432 21439 21458 21510 21542 21635 21638 21647 21655-21656 21665 22033 22088 22212 22240 22243 22249 22253 22258 22266 23635 23637-23638 23717 23764 23774 23795 23851 23969 23982 23984 23996 23998 24179 24189 24325 24328 24362 24451 24499 24554 28729 28801 28803 28819 28830 28833 28839 28848 28890-28892 28900 28912-28913 28915 29036 29089 29091-29092 29094-29098 29100-29101 29103 29116 29118 29158 29162 29167 29461 29463 29467 29489 29507 29510 29512-29513 29515 29517 29530 29537 30216 30242 30258-30259 30269 30303 30312-30313 30318-30319 30328 30405 30419 30425 30474 30618 30622 30627 30644 30691 30694 30719 31748 32034 37212-37213 37247 37339-37340 37363 37366-37367 37371 37723 37725 37743 37750 37758 37833 37850-37851 37861 37863 37870 37880 37886 37897 37899-37901 37906-37907 37920-37921 37923 37926 37930 37932 37934 37995 38020 38022 38024 38026 39222 39236 39238-39239 39244-39245 39248-39250 39252-39254 39264 39369 39374 39384 39386 39410 39708 39711 39733 39749 39770 39793 39799 39802 39804 39895 39905 39909 39930 39971 40612 41454 41471 41584 41595 41598-41599 41610 41630 41646 41652 41654-41655 41663 41671 41673-41675 41680 41685-41686 41696-41698 41702 41707 41747 41750 41756 41758 41772 41779 41781 41783 41787 41793 41796 41817 41820 42154 42169-42170 42172-42173 42203 42206 42209 42216-42217 42226 42283 42303 42335 42346 42376 42383 42387 42390 42392 42394-42395 42405 42407 42416-42417 42421 42436 42438 42444-42445 42456-42458 42461-42462 42464 42470-42471 42483 42496 42513 42562 42977 43021 43023-43024 43026 43030 43034 43041-43043 43049 43796https://cdsarc.cds.unistra.fr/viz-bin/moc/J/other/RAA/18.146?format=asciiOpticalRadiodefaultJ/other/RAA/18.146/table2Parallaxes and proper motions of masersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameMaser namemeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainplxParallaxmaspos.parallax.trigfloate_plxrms uncertainty on plxmasstat.error;pos.parallaxfloatpmRAProper motion along RA (pmRA*cosDE)mas/yrpos.pm;pos.eq.rafloate_pmRArms uncertainty on pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatVlsrLSR velocitykm/sphys.veloc;pos.lsrinte_Vlsrrms uncertainty on Vlsrkm/sstat.error;phys.veloc;pos.lsrintArmSpiral arm in which it residesmeta.id.parentcharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latdoubleJ/other/RAA/18.146/table3Parallaxes and proper motions of O StarsNameStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRA_ICRSRight ascension (ICRS) at epoch 2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) at epoch 2015.5degpos.eq.dec;meta.mainPlxGaia DR2 Parallaxmaspos.parallaxdoublee_Plxrms uncertainty on Plxmasstat.error;pos.parallaxdoublepmRAGaia DR2 Proper motion along RA (pmRA*cosDE)mas/yrpos.pm;pos.eq.radoublee_pmRArms uncertainty on pmRAmas/yrstat.error;pos.pm;pos.eq.radoublepmDEGaia DR2 Proper motion along DEmas/yrpos.pm;pos.eq.decdoublee_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decdoubleVlsr? LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_Vlsr? rms uncertainty on Vlsrkm/sstat.error;phys.veloc;pos.lsrfloatnullableSpTypeSpectral typesrc.spTypecharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latdoubleGaiaDR2Gaia DR2 source numbermeta.idArmSpiral arm in which it residesmeta.id.parentcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexed