Exploring the Sagittarius Stream With SEKBO Survey RR Lyrae Stars

dc.contributor.authorPrior, Sayuri
dc.contributor.authorDa Costa, Gary
dc.contributor.authorKeller, Stefan
dc.date.accessioned2015-12-07T22:33:02Z
dc.date.issued2009
dc.date.updated2016-02-24T09:54:50Z
dc.description.abstractA sample of RR Lyrae (RRL) variables from the Southern Edgeworth-Kuiper Belt Object survey in regions overlapping the expected position of debris from the interaction of the Sagittarius (Sgr) dwarf galaxy with the Milky Way (R.A. 20 and 21.5hr; distance = 16-21kpc) has been followed up spectroscopically and photometrically. The 21 photometrically confirmed type ab RRLs in this region have 〈[Fe/H]〉 = 〈1.79 〉 0.08 on our system, consistent with the abundances found for RRLs in a different portion of the Sgr tidal debris stream. The distribution of velocities in the Galactic standard of rest frame (VGSR) of the 26 RRLs in the region is not consistent with a smooth halo population. Upon comparison with the Sgr disruption models of Law etal., a prominent group of five stars having highly negative radial velocities (VGSR -175 km s-1) is consistent with predictions for old trailing debris when the Galactic halo potential is modeled as oblate. In contrast, the prolate model does not predict any significant number of Sgr stars at the locations of the observed sample. The observations also require that the recent trailing debris stream has a broader spread perpendicular to the Sgr plane than predicted by the models. We have also investigated the possible association of the Virgo Stellar Stream (VSS) with Sgr debris by comparing radial velocities for RRLs in the region with the same models, finding similarities in the velocity-position trends. As suggested by our earlier work, the stars in the VSS region with large negative VGSR values are likely to be old leading Sgr debris, but we find that while old trailing Sgr debris may well make a contribution at positive VGSR values, it is unlikely to fully account for the VSS feature. Overall we find that further modeling is needed, as trailing arm data generally favor oblate models while leading arm data favor prolate models, with no single potential fitting all the observed data.
dc.identifier.issn0004-637X
dc.identifier.urihttp://hdl.handle.net/1885/23077
dc.publisherIOP Publishing
dc.sourceAstrophysical Journal, The
dc.subjectKeywords: Galaxy: halo; Galaxy: kinematics and dynamics; Galaxy: structure; Stars: variables: other
dc.titleExploring the Sagittarius Stream With SEKBO Survey RR Lyrae Stars
dc.typeJournal article
local.bibliographicCitation.issue2
local.bibliographicCitation.lastpage1340
local.bibliographicCitation.startpage1327
local.contributor.affiliationPrior, Sayuri, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationDa Costa, Gary, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationKeller, Stefan, College of Physical and Mathematical Sciences, ANU
local.contributor.authoremailu2519876@anu.edu.au
local.contributor.authoruidPrior, Sayuri, u2519876
local.contributor.authoruidDa Costa, Gary, u9501331
local.contributor.authoruidKeller, Stefan, u9702857
local.description.embargo2037-12-31
local.description.notesImported from ARIES
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationu3356449xPUB25
local.identifier.citationvolume704
local.identifier.doi10.1088/0004-637X/704/2/1327
local.identifier.scopusID2-s2.0-70549086898
local.identifier.thomsonID000270486200026
local.identifier.uidSubmittedByu3356449
local.type.statusPublished Version

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