The Aquarius comoving group is not a disrupted classical globular cluster

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dc.contributor.authorCasey, A. R.
dc.contributor.authorKeller, S. C.
dc.contributor.authorAlves-Brito, A.
dc.contributor.authorFrebel, A.
dc.contributor.authorDa Costa, G.
dc.contributor.authorKarakas, A.
dc.contributor.authorYong, D.
dc.contributor.authorSchlaufman, K. C.
dc.contributor.authorJacobson, H. R.
dc.contributor.authorYu, Q.
dc.contributor.authorFishlock, C.
dc.date.accessioned2025-01-23T21:43:08Z
dc.date.available2025-01-23T21:43:08Z
dc.date.issued2014
dc.description.abstractWe present a detailed analysis of high-resolution, high signal-to-noise ratio spectra for five Aquarius stream stars observed with the Magellan Inamori Kyocera Echelle spectrograph on the Magellan Clay telescope. Our sample represents one-third of the 15 known members in the stream. We find the stream is not monometallic: the metallicity ranges from [Fe/H] = -0.63 to -1.58. No anticorrelation in Na-O abundances is present, and we find a strong positive Mg-Al relationship, similar to that observed in the thick disc. We find no evidence that the stream is a result of a disrupted classical globular cluster, contrary to a previously published claim. High [(Na, Ni, alpha)/Fe] and low [Ba/Y] abundance ratios in the stream suggest that it is not a tidal tail from a disrupted dwarf galaxy, either. The stream is chemically indistinguishable from Milky Way field stars with the exception of one candidate, C222531-145437. From its position, velocity, and detailed chemical abundances, C222531-145437 is likely a star that was tidally disrupted from omega-Centauri. We propose that the Aquarius stream is Galactic in origin, and could be the result of a disc-satellite perturbation in the Milky Way thick disc of the order of a few Gyr ago: derived orbits, UVW velocities, and angular momenta of the Aquarius members offer qualitative support for our hypothesis. Assuming that C222531-145437 is a tidally disrupted member of omega-Centauri, this system is the most likely disc perturber. In the absence of compelling chemical and/or dynamical evidence that the Aquarius stream is the tidal tail of a disrupted satellite, we advocate the 'Aquarius group' as a more appropriate description. Like the Canis Major overdensity, as well as the Hercules and Monoceros groups, the Aquarius group joins the list of kinematically identified substructures that are not actually accreted material: they are simply part of the rich complexity of the Milky Way structure.
dc.fuente.origenWOS
dc.identifier.doi10.1093/mnras/stu1031
dc.identifier.eissn1365-2966
dc.identifier.issn0035-8711
dc.identifier.urihttps://doi.org/10.1093/mnras/stu1031
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/101671
dc.identifier.wosidWOS:000339927000065
dc.issue.numero1
dc.language.isoen
dc.pagina.final851
dc.pagina.inicio828
dc.revistaMonthly notices of the royal astronomical society
dc.rightsacceso restringido
dc.subjectGalaxy: halo
dc.subjectGalaxy: structure
dc.titleThe Aquarius comoving group is not a disrupted classical globular cluster
dc.typeartículo
dc.volumen443
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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