J/A+A/701/A136ivo://CDS.VizieR/J/A+A/701/A136doi:10.26093/cds/vizier/bc-nx/lbdgCDSCabrera-Gadea M.Mateu C.Ramos P.2026-08-03T06:56:56Z2025-09-09T10:53:26ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyvariable-starsstellar-distancemetallicityvisible-astronomyThe outskirts of the Milky Way disc have been known to be warped since the late 1950s. Although various stellar populations have shown an underlying warped distribution, the relation between the age of the population and the warp they trace remains an open question. Understanding this relation may shed light on the origin of the warp which remains a puzzle to be solved. Our goal in this work is to detect the presence of the warp in the RR Lyrae (RRL) population of the Milky Way disc. We use a compilation of the three largest public catalogues of RRL stars, precise photometric distances (~5%) and Gaia DR3 proper motions to kinematically select a sample of thin disc RRL in the Galactic anticentre, where the tangential velocity best approximates the azimuthal velocity to differentiate between those that rotate (disc) and those that do not (halo). For those disc-like RRL we analyse their mean vertical height and mean vertical velocity. We show, for the first time, that RRL stars with thin disc-like kinematics trace the warp. In the anticentre direction, the RRL population reaches a minimum in mean vertical height of ~0.4kpc, with a trend systematically lower than the one found with Classical Cepheids. The kinematical signal of the RRL warp starts at R~10kpc and, rather than resembling the Cepheid's, shows a similar trend to the Red Clump population from previous works, reaching a maximum value of ~7km/s in vertical velocity. We also obtain an estimation of the pattern speed of the RRL warp with a prograde rotation of ~13+/-2km/s/kpc, compatible with results obtained from Classical Cepheids. Finally, we also obtain a vertical velocity dispersion ~17km/s, inconsistent with the kinematics of a canonical old age (>10Gyr) disc population and, instead, favouring a population dominated by intermediate-age (3-4Gyr). Our results indicate that the thin disc RRL stars are a dynamical intermediate-age tracer of the warp, opening a new window to study the dependency of the warp with stellar age in the Milky Way.2025A&A...701A.136Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/701/A136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/AJ/153/204 : RR Lyrae stars from the PS1 3{pi} survey (Sesar+, 2017)J/A+A/674/A18 : Gaia DR3. The RR Lyrae sample (Clementini+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/701/A136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/701/A136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/701/A136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/701/A136https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/701/A136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/701/A136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/701/A136/table1 (Catalog of RR Lyrae stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/701/A136/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/701/A136/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/701/A136/table1?GETtext/xml+votable180.050000true57.697952105179120.46892229741080.0055555555555555566/363 514 572 597 1085 1088 1090 1096 1115 1136 1141 1205-1206 1236-1237 1294 1298 1300 1316 1320 1327 1343 1355-1356 1366 1371-1372 1408 1434 1443 1446 1449 1464 1466 1486 1541 1549 1588 1594-1595 1603 1676 1690 1712 1730 1737 1758 1790 1795 1798 1814 1825-1826 1833 1863 1865 1896 1924-1925 1931 1934 1941 1947 1954 1957 1963 1970 2189 2429 2451 2526 2548 2836 2894 2910 2917 2924 3083 3094 3125-3126 3139 3145 3149-3150 3158 3176 3178 3183 3193 3271 3274 3282 3298 3307 3320 3329 3345 3364 3384 3430 3485 3496 3555 3590 3645 3668 3724 3732 3743 3751 3878 4002 4330 4900 6567 6840 6881 6892 6906 6910 6934 7076 7102 7297 7783 7816 7877 7895 12147 13647 14278 14300 15707 15804 15998 16227 16338 18243 18382 19940 20467 20497 20541 20762 20783 20793 20829 20936 20961 20977 21111 21286 21340 21346-21347 21362 21509 21583 21627 21640 21655 21666 21700 21711 21739 21948 21961 22012 22016 22022 22033 22040 22045 22107 22111 22124 22126 22129 22144 22156 22172 22183 22185 22196-22197 22240 22243 22261 22267 22272 22282 22304-22305 22307 22315 22414 22419 22421 22449 22455 22606 22811 22860 22872-22873 22876 22952 22998-22999 23122 23127 23380 23564 23601 23613 23616 23628-23629 23638 23654 23684 23749 23767-23768 23778 23783 23786-23787 23791 23800 23810 23821 23843 23855 23857 23873 23876 23938 23942 23945 23949 23954-23955 23959 23975 23995 23998 24045 24065 24094 24103 24122 24137 24149 24155 24169 24174 24205 24213 24223 24241 24244 24262 24295 24322-24323 24330 24332 24335 24337 24342-24343 24345 24359 24366 24386-24387 24405 24410 24417 24439 24445 24480 24512 24517 24520 24524 24536 24552 24558 27245 27435 34063 34169 34288 34378 35948 36123 36225 36318 39278 39292 39316 39395 39547 39910 40502 40553https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/701/A136?format=asciiOpticaldefaultJ/A+A/701/A136/table1Catalog of RR Lyrae starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia DR3 source IDmeta.id;meta.mainDistHeliocentric distancekpcpos.distancedoublee_DistDistance errorkpcstat.errordoubleGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latpmGLONProper motion in GLONmas/yrpos.pmdoublepmGLATProper motion in GLATmas/yrpos.pmdouble[Fe/H]Metallicity used for distance calculationphys.abund.Z;instr.setupdoublePerPeriod of the RR Lyrae stardtime.perioddoubleAmpVV-band amplitude of the RR Lyraemagphot.magdoublef_[Fe/H][0/1] Metallicity flag: 1=photometric, 0=assignedmeta.codeintSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000. (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.raindexed_DE.icrsDeclination (ICRS) at Epoch=J2000. (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decindexedJ/A+A/701/A136/table2Results from RR Lyrae samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRMean Galactocentric radiuskpcpos.distance;pos.galactocentricfloatZMean vertical heightkpcpos.cartesian.z;pos.galacticfloats_ZStandard deviation of Z (bootstrap)kpcstat.stdev;src.redshiftfloatVzMean vertical velocitykm/sphys.veloc;pos.galactocentricfloats_VzStandard deviation of Vz (bootstrap)km/sstat.stdevfloatstdVzStandard deviation of vertical velocitykm/sphys.veloc.dispersionfloats_stdVzStandard deviation of stdVz (bootstrap)km/sstat.stdevfloatmedianOmegaMedian pattern speedkm.s**-1.kpc**-1arith.grad;phys.velocfloatb_medianOmega15% percentile of omega distributionkm.s**-1.kpc**-1arith.grad;phys.veloc;stat.minfloatB_medianOmega85% percentile of omega distributionkm.s**-1.kpc**-1arith.grad;phys.veloc;stat.maxfloatmeanVphiMean azimuthal velocitykm/sphys.veloc;stat.meanfloate_meanVphiStandard deviation of Vphi (bootstrap)km/sstat.errorfloat