J/AJ/165/100ivo://CDS.VizieR/J/AJ/165/100doi:10.26093/cds/vizier.51650100CDSJi A.P.Simon J.D.Roederer I.U.Magg E.Frebel A.Johnson C.I.,Klessen R.S.Magg M.Cescutti G.Mateo M.Bergemann M.Bailey J.I.I.2024-10-07T20:09:25Z2023-06-21T06:46:04ZCDS support team

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

cds-question@unistra.frdwarf-galaxiesvisible-astronomyspectroscopychemical-abundancesproper-motionsradial-velocityeffective-temperatureThe ultrafaint dwarf galaxy ReticulumII was enriched by a single rare and prolific r-process event. The r-process content of ReticulumII thus provides a unique opportunity to study metal mixing in a relic first galaxy. Using multi-object high-resolution spectroscopy with VLT/GIRAFFE and Magellan/M2FS, we identify 32 clear spectroscopic member stars and measure abundances of Mg, Ca, Fe, and Ba where possible. We find 72_-12_^+10^% of the stars are r-process-enhanced, with a mean <Ba/H>=-1.68{+/-}0.07 and unresolved intrinsic dispersion {sigma}[Ba/H]<0.20. The homogeneous r-process abundances imply that RetII's metals are well mixed by the time the r-enhanced stars form, which simulations have shown requires at least 100Myr of metal mixing in between bursts of star formation to homogenize. This is the first direct evidence of bursty star formation in an ultrafaint dwarf galaxy. The homogeneous dilution prefers a prompt and high-yield r-process site, such as collapsar disk winds or prompt neutron star mergers. We also find evidence from [Ba/H] and [Mg/Ca] that the r-enhanced stars in RetII formed in the absence of substantial pristine gas accretion, perhaps indicating that ~70% of RetII stars formed after reionization.2023AJ....165..100Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/165/100CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/simbad : Simbad objects catalogue (M.Wenger 2000)I/337 : Gaia DR1 (Gaia Collaboration, 2016)II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004)J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)J/ApJ/645/613 : Abundances of HD 221170 (Ivans+, 2006)J/MNRAS/383/183 : CaII triplet of RGB from VLT/FLAMES obs. (Battaglia+, 2008)J/A+A/490/625 : Abundances of NGC 6121 red giants (Marino+, 2008)J/ApJ/708/560 : Spectroscopy of UMa II and Coma Ber (Frebel+, 2010)J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)J/ApJ/769/57 : Equivalent widths of metal-poor stars (Frebel+, 2013)J/ApJ/778/149 : Abundances for 3 stars in Sgr dSph (McWilliam+, 2013)J/ApJ/767/134 : Abundances of red giant stars in UFD galaxies (Vargas+, 2013)J/MNRAS/444/392 : Synthetic Stellar Photometry. I. (Casagrande+, 2014)J/ApJ/786/74 : EW measurements of 6 Segue 1 red giants (Frebel+, 2014)J/A+A/569/A43 : HE 2252-4225 abundance analysis (Mashonkina+, 2014)J/AJ/147/136 : Stars of low metal abundance VI. Abundances (Roederer+, 2014)J/ApJ/789/147 : Star formation histories of LG dwarf galaxies (Weisz+, 2014)J/ApJ/807/171 : SkyMapper Survey metal-poor star spectro. (Jacobson+, 2015)J/ApJ/808/95 : Spectroscopy of Reticulum II (Simon+, 2015)J/ApJ/808/108 : M2FS stellar spectroscopy of Reticulum 2 (Walker+, 2015)J/ApJ/826/110 : Boo-127 and Boo-980 high-resolution spectra (Frebel+, 2016)J/ApJ/830/93 : Abundances of Ret II brightest red giant members (Ji+, 2016)J/ApJ/817/41 : Abundances of 4 metal-poor red giants in BooII (Ji+, 2016)J/AJ/151/82 : 4 brightest red giants in UFD galaxy Ret 2 (Roederer+, 2016)J/ApJ/838/44 : Abundances of the brightest member of Tuc III (Hansen+, 2017)J/ApJ/838/11 : Member stars in the MW satellite Tucana III (Simon+, 2017)J/MNRAS/479/5343 : Nearby dwarf galaxy in Magellanic bridge (Koposov+, 2018)J/ApJ/857/145 : MagLiteS Carina II and Carina III spectroscopy (Li+, 2018)J/ApJS/237/13 : Models & yields of 13-120Msun massive stars (Limongi+, 2018)J/ApJ/863/25 : Magellan/Megacam obs of 4 MW satellites (Mutlu-Pakdil+, 2018)J/A+A/631/A80 : Mn lines 3D NLTE formation late-type stars (Bergemann+, 2019)J/A+A/626/A15 : Sculptor Red Giant Branch stars abundances (Hill+, 2019)J/ApJ/882/40 : Lanthanide fraction distribution metal-poor stars (Ji+, 2019)J/ApJ/870/83 : Abundances in ultra-faint dwarf gal. GruI & TriII (Ji+, 2019)J/MNRAS/490/3508 : The Southern Stellar Stream Sp. Survey (S^5^) (Li+, 2019)J/ApJ/897/183 : Chemical abundances 3 stars in Grus II galaxy (Hansen+, 2020)J/AJ/160/181 : Chemical abundances in red giants with Magellan (Ji+, 2020)J/ApJ/889/27 : Abundances of 11 stars in Carina II and III (Ji+, 2020)J/AJ/159/46 : Elemental abundances416 stars in 5 M31 dSphs (Kirby+, 2020)J/ApJ/892/137 : Spectroscopy of Grus II, Tuc IV and Tuc V (Simon+, 2020)J/A+A/642/A176 : Chemical evolution of dSph galaxy Sextans (Theler+, 2020)J/ApJ/906/96 : Dwarfs galaxies in DC Justice League Simul (Applebaum+, 2021)J/ApJ/921/67 : High-dispersion sp. 8 Phoenix stream redgiants (Casey+, 2021)J/A+A/657/A54 : Local Group Gaia eDR3 systemic motions (Battaglia+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/165/100https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/165/100http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/165/100https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/165/100https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/165/100http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/165/100GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/165/100/table1 (Observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/165/100/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/165/100/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/165/100/table1?GETtext/xml+votable180.050000true53.849167-54.0687940.0055555555555555566/33626-33627https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/165/100?format=asciiOpticaldefaultJ/AJ/165/100/table1ObservationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadSimbad column added by the CDSmeta.ref.urlcharID[1/200] Internal index identifiermeta.id;meta.numberintprimaryRAJ2000[3/3] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[53/54] Degree of Declination (J2000)pos.eq.dec;meta.maingmag[16/21] Extinction corrected, apparent g bandmagphot.mag;em.opt.Vfloatrmag[15.6/20.7] Extinction corrected, apparent r band magnitudemagphot.mag;em.opt.Rfloatre/rh[0.23/4.78] Elliptical distance divided by half-light radiusstat.fit.omcfloatRVel[-492/345] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVel[0.1/12] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloatpmRA[-3.73/35.2] Proper motion along RA*cos(DEC)mas/yrpos.pm;pos.eq.rafloatpmDE[-23/22.1] Proper motion along DECmas/yrpos.pm;pos.eq.decfloatMem[0/1] Member? 1=True and 0=Falsemeta.code.memberintCanMem[0/1] Candidate member? 1=True and 0=Falsemeta.code.memberintBin[0/1] Binary? 1=True and 0=Falsemeta.codeintVLT-SNVLT Signal-to-Noise Ratio, per pixelstat.snr;instr.pixelcharM2FSM2FS filter used; b or rmeta.code;instr.filtercharhighSN[2/40]? M2FS hi-resolution Signal-to-Noise Ratio, per pixelstat.snrfloatnullablemedSN[22/94]? M2FS medium-resolution Signal-to-Noise, per pixelstat.snrintnullableGaiaGaia EDR3 identifiermeta.id;meta.mainVLT-RVel[-490/348]? VLT heliocentric velocity from H{alpha}km/sphys.veloc;pos.heliocentricfloatnullablee_VLT-RVel[0.6/3]? Uncertainty in VLT-Hakm/sstat.errorfloatnullablehighRVel[0/133]? M2FS high-resolution heliocentric velocitykm/sphys.veloc;pos.heliocentricfloatnullablee_highRVel[0/4.25]? Uncertainty in M2FS-vHelkm/sstat.errorfloatnullablemedRVel[45.1/66.9]? M2FS medium-resolution heliocentric velocitykm/sphys.veloc;pos.heliocentricfloatnullableParam*If >0 indicates the availabiliy of stellar parameters (table2)meta.numberintnullableAbundIf >0 indicates the availabiliy of abundance data (table4)meta.numberintnullableJ/AJ/165/100/table2*Stellar parametersID[1/195] Internal index identifiermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTeff[4584/6645] Effective temperatureKphys.temperature.effectiveinte_Teff[49/130] Error on TeffKstat.error;phys.temperature.effectiveintlogg[1.24/3.81] Surface gravityphys.gravityfloate_logg[0.1/0.2] Error on loggstat.errorfloatVt[1.26/1.61] Turbulence velocitykm/sphys.veloc.microTurbfloate_Vt[0.1/0.2] Error on Vtkm/sstat.errorfloatJ/AJ/165/100/table4*AbundancesBa/H-MR[-1.82/-0.83]? log Ba ration, MRphys.abundfloatnullablee_Ba/H-MR[0.16/0.87]? Error on Ba/H-MRstat.error;phys.abundfloatnullableMemMembership (1)meta.code.membercharID[1/195] Internal index identifiermeta.id;meta.mainintFe/H[-3.28/-0.37]? log Fe ratiophys.abund.Fe;arith.zpfloatnullablee_Fe/H[0.08/0.44]? Error on Fe/Hstat.error;phys.abund.Fefloatnullablef_Fe/H[*] Flag on Fe/H (2)meta.codecharBa/H-NLTE[-3.46/0.79]? log Ba ratio, NLTEphys.abundfloatnullablee_Ba/H-NLTE[0.15/0.71]? Error on Ba/H-NLTEstat.error;phys.abundfloatnullablef_Ba/H-NLTE[*] Flag on Ba/H-NLTE (2)meta.codecharBa/H-LTE[-3.46/0.79]? log Ba ratio, LTEphys.abundfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVLT-SN[7/140]? Very Large Telescope signal-to-noisestat.snrintnullableM2FS-SNM2FS signal-to_noisestat.snrcharMg/H[-2.84/-2.03]? log Mg ratiophys.abundfloatnullablee_Mg/H[0.11/0.22]? Error on Mg/Hstat.error;phys.abundfloatnullableCa/H[-2.98/0.34]? log Ca ratiophys.abundfloatnullablee_Ca/H[0.06/0.23]? Error on Ca/Hstat.error;phys.abundfloatnullablef_Ca/H[*] Flag on Ca/H (2)meta.codecharf_Ba/H-MR[*] Flag on Ba/H-MR (2)meta.codechar