J/MNRAS/493/5195ivo://CDS.VizieR/J/MNRAS/493/5195doi:10.26093/cds/vizier.74935195CDSDas P.Hawkins K.Jofre P.2024-08-20T20:16:52Z2020-08-03T08:53:09ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyhalo-starschemical-abundancesstellar-agesWe exploit the [Mg/Mn]-[Al/Fe] chemical abundance plane to help identify nearby halo stars in the 14th data release from the APOGEE survey that have been accreted on to the Milky Way. Applying a Gaussian Mixture Model, we find a 'blob' of 856 likely accreted stars, with a low disc contamination rate of about 7 percent. Cross-matching the sample with the second data release from Gaia gives us access to parallaxes and apparent magnitudes, which place constraints on distances and intrinsic luminosities. Using a Bayesian isochrone pipeline, this enables us to estimate new ages for the accreted stars, with typical uncertainties of 20 percent. Our new catalogue is further supplemented with estimates of orbital parameters. The blob stars span a metallicities between -0.5 to -2.5, and [Mg/Fe] between -0.1 to 0.5. They constitute 30 percent of the metal-poor ([Fe/H]<-0.8) halo at metallicities of -1.4. Our new ages are mainly range between 8 to 13Gyr, with the oldest stars the metal-poorest, and with the highest [Mg/Fe] abundance. If the blob stars are assumed to belong to a single progenitor, the ages imply that the system merged with our Milky Way around 8 Gyr ago and that star formation proceeded for 5Gyr. Dynamical arguments suggest that such a single progenitor would have a total mass of 10^11^M_{sun}_, similar to that found by other authors using chemical evolution models and simulations. Comparing the scatter in the [Mg/Fe]-[Fe/H] plane of the blob stars to that measured for stars belonging to the Large Magellanic Cloud suggests that the blob does indeed contain stars from only one progenitor.2020MNRAS.493.5195Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/493/5195CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/493/5195https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/493/5195http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/493/5195https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/493/5195https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/493/5195http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/493/5195GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/493/5195/blob (Catalogue of the spectroscopic, age, and kinematic properties of the blob stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/493/5195/blob?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/493/5195/blob?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/493/5195/blob?GETtext/xml+votable180.050000true50.6938857.5409660.0055555555555555566/76 147 153 165 381 467 470 551 556 1015 1058 1291 1323 1436 1532 1559 1752 1792 1825 1980 2432 2440 3530 3598 3758 3766 4033 4072-4074 4108 4133 4253 4276 4278-4279 4320 4537 4674 4681 4704 4826 4852 4859 4880 4933 4935 4941 5081 5139 5147-5148 5225-5226 5336 5338 5360 5362 5372 5492 5494 5528 5531 5534 5536 5554-5555 5557-5558 5560 5562 5566-5567 5584 5600 5614 5670 5677 5681 5683 5688-5689 5715 5740-5741 5743 5747 5749 5755 5758 5799 5802 5807 5836 5838 5840 5847 5888-5890 5916-5917 5919 5923-5924 5928 5953 5958 5960 5962 5965 6160 6175 6224 6270 6364 6367 6389 6391 6393 6396 6404 6458 6485 6531 6536-6538 6556 6559 6561 6567 6577 6624 6631 6644 6646 6651 6689 6696 6723 6834 6917 6996 7236 7274 7318 7320 7360 7372 7680 7743 7767 7785 8092-8093 8335 8359 8374 8381 8429 8440 8443 8446 8699 8702 8865-8870 8873 8940 8942 8963 8965 8967 8969 8972 9015 9029 9031 9045 9070-9071 9082 9152-9154 9156-9158 9160 9168 9200 9210 9213 9216 9253 9255 9257-9258 9261 9267 9273 9335 9362 9370 9373 9375 9416 9431 9436 9438 9440 9461 9463 9465-9466 9471 9473 9478 9493 9495 9505 9509-9510 9512-9513 9515 9520 9536 9598 9601 9607 9609 9634 9641-9642 9644 9646 9666-9667 9707 9779 9782 9787 9805 9807 9813 9815 9819 9823 9828 9840 9848 9850 9854-9855 9886-9887 9914 9923 9936 9944 9949 9957 9962 9993 10010 10017 10025-10026 10097 10099 10112 10121 10126 10181 10194 10199-10200 10204-10205 10211 10215 10245 10269 10288-10289 10293-10294 10300 10308 10320 10323 10336-10337 10365 10376 10378 10382 10404 10484 10488 10493 10583 10598 10606 10662-10663 10668 10700 10703 10705-10706 10710 10712 10714 10861 10872 10894-10895 10913 10932 10934-10936 10938 10940 10947 10950 10953 10976-10978 11033 11040-11041 11052 11097 11118 11124 11131 11186-11187 11190-11191 11274-11275 11278 11297-11298 11302 11312-11313 11329 11349 11357-11358 11393 11404 11407-11409 11412 11414 11424 11433 11596 11786 11981 11986 12274 12390 12392 12396 12398 12408 12576 12900 12918 12994 13808 13855 13913 13921 14225 14518 14781 14923 14931 14955 14973 15041 15057 15104 15116 15132 15139-15140 15142 15146 15158 15160 15549 15806 16115 16639 16983 16989 17172-17173 17216 17750 17796 18419 18425 18430 18777 18780 19013 19015 19024 19026 19091 19094 19099-19100 19228 19230-19231 19698-19699 19773-19775 19975 20382 21371 21860 21863 22087 22227 22236 22254 22405 22699 22851 23056 23059 23191 23193 23220 23234 23725 23770 23977 24025 24061 24080 24283 25336 25384 25387 25489 25589 25595 25849 25851 25854 25880 26028 26039 26074-26075 26100 26115 26118 26121 26190 26193 26247 26249 26266 26272 26283 26592 26598 26604 26653 26704-26705 26721-26723 26921 26963 26973 26987 26996 27003 27007 27009 27045 27056 27072-27073 27093 27127 27132-27133 27231 27487 27623 27628-27629 27677 27775 27863 27894 27900-27902 27909 27913 27947 27969 27981 28032 28072 28127 28148-28149 28247 28252 28271 28282 28286 28291 28299 28326-28327 28334 28356 28369 28416 28481 28483 28548 28551 28644 28646 28648-28649 28733 28759 28777 28780 28821 28845 28847 28851-28852 28865 28889 28911 28929 28932 28941 28943 29188 29191 29207 29210 29212-29213 29231 29298 29307 29349-29350 29441 29459 29548 29550 29664 29672-29674 29691 29755 29877 29892 29922 30231 30295 30342 30386 30392-30393 30464 30772 30862 30884 31115 31146 31374 31393 31396 31398 31408 31410-31411 31416-31417 31420 31445 31447 31578 31583 31604-31606 31773 32029 32134 32150-32151 32463 32500-32501 32508 36351 36743 36772 36784 40748 40820 40829 44981 45003 45024-45025 48035 48040 48042 48044 480471.1166583743361574e-19 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/493/5195?format=asciidefaultJ/MNRAS/493/5195/blobCatalogue of the spectroscopic, age, and kinematic properties of the blob stars[Ni/Fe]Abundance [Ni/Fe] (apogee_ni_fe)phys.abunddoubleSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLocAPOGEE location ID (apogee_location_id)meta.idintJmag2MASS J magnitude (J)magphot.mag;em.IR.JfloatHmag2MASS H magnitude (H)magphot.mag;em.IR.HfloatKmag2MASS K magnitude (K)magphot.mag;em.IR.Kfloate_Jmagrms uncertainty on Jmag (J_ERR)magstat.error;phot.magfloate_Hmagrms uncertainty on Hmag (H_ERR)magstat.error;phot.magfloate_Kmagrms uncertainty on Kmag (K_ERR)magstat.error;phot.magfloatRAJ2000Right ascension (J2000) (RA)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (DEC)degpos.eq.dec;meta.mainHVAverage heliocentric velocity (apogee_vhelio_avg)km/sspect.dopplerVeloc;pos.heliocentric;stat.meandoublee_HVrms uncertainty on HV (apogee_verr)km/sstat.errordoubleloggSyrface gravity (apogee_logg)log(cm**2.s**-1)phys.gravitydoublee_loggrms uncertainty on loog (apogee_logg_err)log(cm**2.s**-1)stat.errordoubleTeffEffective temperature (apogee_teffKphys.temperature.effectivedoublee_Teffrms uncertainty on Teff (apogee_teff_err)Kstat.error;phys.temperature.effectivedouble[M/H]Metallicity (apogee_m_h)phys.abund.Zdoublee_[M/H]rms uncertainty on [M/H] (apogee_m_h_err)stat.error;phys.abunddouble[alpha/M]Alpha-element enhancement (apogee_a_m_)phys.abunddoublee_[alpha/M]rms uncertainty on [alpha/M] (apogee_a_m_err)stat.errordouble[C/Fe]Abundance [C/Fe] (apogee_c_fe)phys.abunddoublee_[C/Fe]rms uncertainty on [C/Fe] (apogee_c_fe_err)stat.error;phys.abunddouble[N/Fe]Abundance [N/Fe] (apogee_n_fe)phys.abunddoublee_[N/Fe]rms uncertainty on [N/Fe] (apogee_n_fe_err)stat.error;phys.abunddouble[O/Fe]? Abundance [O/Fe] (apogee_o_fe)phys.abunddoublenullablee_[O/Fe]? rms uncertainty on [O/Fe] (apogee_o_fe_err)stat.error;phys.abunddoublenullable[Na/Fe]? Abundance [Na/Fe] (apogee_na_fe)phys.abunddoublenullablee_[Na/Fe]? rms uncertainty on [Na/Fe] (apogee_na_fe_err)stat.error;phys.abunddoublenullable[Mg/Fe]Abundance [Mg/Fe] (apogee_mg_fe)phys.abunddoublee_[Mg/Fe]rms uncertainty on [Mg/Fe] (apogee_mg_fe_err)stat.error;phys.abunddouble[Al/Fe]Abundance [Al/Fe] (apogee_al_fe)phys.abunddoublee_[Al/Fe]rms uncertainty on [Al/Fe] (apogee_al_fe_err)stat.error;phys.abunddouble[Mn/Fe]Abundance [Mn/Fe] (apogee_mn_fe)phys.abunddoublee_[Mn/Fe]rms uncertainty on [Mn/Fe] (apogee_mn_fe_err)stat.error;phys.abunddoublee_[Ni/Fe]rms uncertainty on [Ni/Fe] (apogee_ni_fe_err)stat.error;phys.abunddouble[Y/Fe]? Abundance [Y/Fe] (apogee_y_fe)phys.abundintnullablee_[Y/Fe]? rms uncertainty on [Y/Fe] (apogee_y_fe_err)stat.error;phys.abundintnullableGaiaDR2Gaia DR2 identifier (gaia_source_id)meta.idlogAgeNew age (log10_age_new)log(Gyr)time.agedoublee_logAgerms uncertainty on Age (log10_age_err_new)log(Gyr)stat.error;time.agedoubleMODNew distance modulus (dm_new)phot.mag.distModdoublee_MODrms uncertainty on MOD (dm_err_new)stat.errordoubleJRNew radial action (JR_new)kpc.km/sarith.grad;phys.velocdoubleJzNew vertical action (Jz_new)kpc.km/sarith.grad;phys.velocdoubleLzNew z component of angular momentum (Lz_new)kpc.km/spos.cartesian.zdoublesNew Galactocentric azimuth angle distance (s_new)kpcpos.distance;pos.posAng;pos.galactocentricdoubleRNew Galactocentric radius distance (R_new)kpcpos.distance;phys.size.radius;pos.galactocentricdoublezNew height above Galactocentric plane distance (z_new)kpcpos.distance;pos.cartesian.z;pos.galactocentricdoubleAPOGEEAPOGEE name, 2MHHMMSSss+DDMMSSs (apogee_id)meta.id;meta.mainchar