J/MNRAS/530/2972ivo://CDS.VizieR/J/MNRAS/530/2972doi:10.26093/cds/vizier.75302972CDSSanders J.L.Kawata D.Matsunaga N.Sormani M.C.Smith L.C.Minniti D.,Gerhard O.2026-08-03T07:33:11Z2024-05-15T12:40:01ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyvariable-starsinfrared-photometryorbitsA key event in the history of the Milky Way is the formation of the bar. This event affects the subsequent structural and dynamical evolution of the entire Galaxy. When the bar formed, gas was likely rapidly funnelled to the centre of the Galaxy settling in a star-forming nuclear disc. The Milky Way bar formation can then be dated by considering the age distribution of the oldest stars in the formed nuclear stellar disc. In this highly obscured and crowded region, reliable age tracers are limited, but bright, high-amplitude Mira variables make useful age indicators as they follow a period--age relation. We fit dynamical models to the proper motions of a sample of Mira variables in the Milky Way's nuclear stellar disc region. Weak evidence for inside-out growth and both radial and vertical dynamical heating with time of the nuclear stellar disc is presented suggesting the nuclear stellar disc is dynamically well-mixed. Furthermore, for Mira variables around a ~350 day period, there is a clear transition from nuclear stellar disc-dominated kinematics to background bar-bulge-dominated kinematics. Using a Mira variable period--age relation calibrated in the solar neighbourhood, this suggests the nuclear stellar disc formed in a significant burst in star formation (8+/-1)Gyr ago, although the data are also weakly consistent with a more gradual formation of the nuclear stellar disc at even earlier epochs. This implies a relatively early formation time for the Milky Way bar (>~8Gyr), which has implications for the growth and state of the young Milky Way and its subsequent history.2024MNRAS.530.2972Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/530/2972CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/530/2972https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/530/2972http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/530/2972https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/530/2972https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/530/2972http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/530/2972GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/530/2972/catalog (Mira variable data set)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/530/2972/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/530/2972/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/530/2972/catalog?GETtext/xml+votable180.050000true266.22758702-29.066342170.0055555555555555565/7206-7207 6/28819 28822 28848-28849 28852-288547.952274030004205e-20 1.0188844282367877e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/530/2972?format=asciiInfrareddefaultJ/MNRAS/530/2972/catalogMira variable data setKsmagModMean Ks magnitude from multiband model (Ks_mean_model)magphot.mag;em.IR.Kdoublee_pmDEUncertainty in VIRAC-2 declination proper motion (pmdec_error)mas/yrstat.error;pos.pm;pos.eq.decdoublepmRApmDEcorVIRAC-2 correlation coefficient between pmRA and pmDE (pmra_pmdec_corr)stat.correlationdoubleplxVIRAC-2 parallax (parallax)maspos.parallax.trigdoublee_plxVIRAC-2 parallax uncertainty (parallax_error)masstat.error;pos.parallaxdoubleSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.raindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVIRAC2Mira[0/1823] Unique VIRAC2 Mira source ID (virac_mira_id)meta.id;meta.mainintRA_ICRSVIRAC-2 right ascension (ICRS) at Ep=2014.0 (ra)degpos.eq.ra;meta.mainDE_ICRSVIRAC-2 declination (ICRS) at Ep=2014.0 (dec)degpos.eq.dec;meta.mainGLONVIRAC-2 Galactic longitude at epoch 2014.0 if proper motion computed (l)degpos.galactic.lonGLATVIRAC-2 Galactic latitude at epoch 2014.0 if proper motion computed (b)degpos.galactic.latdoubleM09Id? ID from Matsunaga et al. (2009MNRAS.399.1709M, Cat. J/MNRAS/399/1709) (M09_id)meta.idintnullableunreliable[0/1] Binary flag if Mira variable classification is unreliable (=1) based on a visual classification of the light curve (unreliable)meta.codeintKsEpochsNumber of VIRAC-2 Ks epochs used in the light curve processing for classification as a Mira variable (Ks_nepochs)meta.numberintPerRecommended period - either from multi- band or single band depending on reliability from visual inspection (period)dtime.perioddoublee_Per? Uncertainty in recommended period (period_error)dstat.errordoublenullableAmpKs amplitude (95th-5th Ks percentile) averaged over a period around each data point (amplitude)magsrc.var.amplitudedoubleTAmp? Ks amplitude (95th-5th Ks percentile) across the total timespan of the data (total_amplitude)magsrc.var.amplitudedoublenullablePerSPeriod from the Ks single band fit. For the last 40 entries, this duplicates the M09 result (period_single)dtime.perioddoublee_PerS? Uncertainty in period_single (period_error_single)dstat.errordoublenullableAmpS? Ks amplitude (95th-5th Ks percentile) from the single band fit averaged over a period around each data point (amplitude_single)magsrc.var.amplitudedoublenullableTAmpS? Ks amplitude (95th-5th Ks percentile) from the single band fit across the total timespan of the data (total_amplitude_single)magsrc.var.amplitudedoublenullablePerMPeriod from the multi-band fit (period_multi)dtime.perioddoublee_PerM? Uncertainty in period_multi (period_error_multi)dstat.errordoublenullableAmpMKs amplitude (95th-5th Ks percentile) from the multi-band fit averaged over a period around each data point (amplitude_multi)magsrc.var.amplitudedoubleTAmpMKs amplitude (95th-5th Ks percentile) from the multi-band fit across the total timespan of the data (total_amplitude_multi)magsrc.var.amplitudedoubleZmag? Mean Z magnitude from VIRAC2 (Z_mean_data)magphot.mag;em.opt.IdoublenullableYmag? Mean Y magnitude from VIRAC2 (Y_mean_data)magphot.mag;em.IR.JdoublenullableJmag? Mean J magnitude from VIRAC2 (J_mean_data)magphot.mag;em.IR.JdoublenullableHmag? Mean H magnitude from VIRAC2 (H_mean_data)magphot.mag;em.IR.HdoublenullableKsmag? Mean Ks magnitude from VIRAC2 (Ks_mean_data)magphot.mag;em.IR.KdoublenullableKsmagModS? Mean Ks magnitude from single-band VVV model fit (Ks_mean_model_single)magphot.mag;meta.modelleddoublenullablee_KsmagModS? Uncertainty in mean Ks magnitude from single- band VVV model fit (Ks_error_model_single)magstat.errordoublenullableZmagMod? Mean Z magnitude from multiband model (Z_mean_model)magphot.mag;em.opt.IdoublenullableYmagMod? Mean Y magnitude from multiband model (Y_mean_model)magphot.mag;em.IR.JdoublenullableJmagMod? Mean J magnitude from multiband model (J_mean_model)magphot.mag;em.IR.JdoublenullableHmagMod? Mean H magnitude from multiband model (H_mean_model)magphot.mag;em.IR.HdoublenullableW1magMod? Mean W1 magnitude from multiband model (W1_mean_model)magphot.mag;em.IR.3-4umdoublenullableW2magMod? Mean W2 magnitude from multiband model (W2_mean_model)magphot.mag;em.IR.4-8umdoublenullablee_ZmagMod? Uncertainty in mean Z magnitude from multiband model (Z_error_model)magstat.error;pos.cartesian.zdoublenullablee_YmagMod? Uncertainty in mean Y magnitude from multiband model (Y_error_model)magstat.errordoublenullablee_JmagMod? Uncertainty in mean J magnitude from multiband model (J_error_model)magstat.errordoublenullablee_HmagMod? Uncertainty in mean H magnitude from multiband model (H_error_model)magstat.errordoublenullablee_KsmagModUncertainty in mean Ks magnitude from multiband model (Ks_error_model)magstat.errordoublee_W1magMod? Uncertainty in mean W1 magnitude from multiband model (W1_error_model)magstat.errordoublenullablee_W2magMod? Uncertainty in mean W2 magnitude from multiband model (W2_error_model)magstat.errordoublenullableAmpZ/Ks? Ratio of Z amplitude to Ks amplitude from multi-band fit (Z_Ks_amplitude_ratio)src.var.amplitude;arith.ratiodoublenullableAmpY/Ks? Ratio of Y amplitude to Ks amplitude from multi-band fit (Y_Ks_amplitude_ratio)src.var.amplitude;arith.ratiodoublenullableAmpJ/Ks? Ratio of J amplitude to Ks amplitude from multi-band fit (J_Ks_amplitude_ratio)src.var.amplitudedoublenullableAmpH/Ks? Ratio of H amplitude to Ks amplitude from multi-band fit (H_Ks_amplitude_ratio)src.var.amplitudedoublenullableAmpW1/Ks? Ratio of W1 amplitude to Ks amplitude from multi-band fit (W1_Ks_amplitude_ratio)src.var.amplitude;arith.ratiodoublenullableAmpW2/Ks? Ratio of W2 amplitude to Ks amplitude from multi-band fit (W2_Ks_amplitude_ratio)src.var.amplitude;arith.ratiodoublenullablee_AmpZ/Ks? Uncertainty in ratio of Z amplitude to Ks amplitude from multi-band fit (Z_Ks_amplitude_ratio_error)stat.errordoublenullablee_AmpY/Ks? Uncertainty in ratio of Y amplitude to Ks amplitude from multi-band fit (Y_Ks_amplitude_ratio_error)stat.errordoublenullablee_AmpJ/Ks? Uncertainty in ratio of J amplitude to Ks amplitude from multi-band fit (J_Ks_amplitude_ratio_error)stat.errordoublenullablee_AmpH/Ks? Uncertainty in ratio of H amplitude to Ks amplitude from multi-band fit (H_Ks_amplitude_ratio_error)stat.errordoublenullablee_AmpW1/Ks? Uncertainty in ratio of W1 amplitude to Ks amplitude from multi-band fit (W1_Ks_amplitude_ratio_error)stat.errordoublenullablee_AmpW2/Ks? Uncertainty in ratio of W2 amplitude to Ks amplitude from multi-band fit (W2_Ks_amplitude_ratio_error)stat.errordoublenullabletau10umOptical depth at 10 microns from radiatively- driven wind model (optical_depth_10micron)phys.absorption.opticalDepthdoubleVexpExpansion velocity from radiatively-driven wind model (expansion_velocity)km/sphys.veloc.expansiondoubledM/dtMass loss rate from radiatively-driven wind model (mass_loss_rate)1e-06solMass.yr**-1phys.mass.lossdoublee_RA_ICRSVIRAC-2 right ascension uncertainty, RA*cos(DE) (ra_error)masstat.error;pos.eq.radoublee_DE_ICRSVIRAC-2 declination uncertainty (dec_error)masstat.error;pos.eq.decdoublepmRAVIRAC-2 right ascension proper motion with cos(DE) factor (pmRA*cosDE) (pmra)mas/yrpos.pm;pos.eq.radoublepmDEVIRAC-2 declination proper motion (pmdec)mas/yrpos.pm;pos.eq.decdoublee_pmRAUncertainty in VIRAC-2 right ascension proper motion with cos (dec) factor (pmra_error)mas/yrstat.error;pos.pm;pos.eq.radoubleplxpmRAcorVIRAC-2 correlation coefficient between parallax and pmRA (parallax_pmra_corr)stat.correlationdoubleplxpmDEcorVIRAC-2 correlation coefficient between parallax and pmDE (parallax_pmdec_corr)stat.correlationdoubleastfituweVIRAC-2 astrometric fit unit weight error (chisq per degree of freedom) (astfit_uwe)stat.errordouble