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Hunting the parent of the orphan stream: Identifying stream members from low-resolution spectroscopy

Casey, Andrew; Da Costa, Gary; Keller, Stefan; Maunder, Elizabeth

Description

We present candidate K-giant members in the Orphan Stream that have been identified from low-resolution data taken with the AAOmega spectrograph on the Anglo-Australian Telescope. From modest signal-to-noise spectra and independent cuts in photometry, kinematics, gravity, and metallicity we yield self-consistent, highly probable stream members. We find a revised stream distance of 22.5 ± 2.0 kpc near the celestial equator and our kinematic signature peaks at V GSR = 82.1 ± 1.4 km s-1. The...[Show more]

dc.contributor.authorCasey, Andrew
dc.contributor.authorDa Costa, Gary
dc.contributor.authorKeller, Stefan
dc.contributor.authorMaunder, Elizabeth
dc.date.accessioned2015-12-13T22:16:29Z
dc.identifier.issn0004-637X
dc.identifier.urihttp://hdl.handle.net/1885/70885
dc.description.abstractWe present candidate K-giant members in the Orphan Stream that have been identified from low-resolution data taken with the AAOmega spectrograph on the Anglo-Australian Telescope. From modest signal-to-noise spectra and independent cuts in photometry, kinematics, gravity, and metallicity we yield self-consistent, highly probable stream members. We find a revised stream distance of 22.5 ± 2.0 kpc near the celestial equator and our kinematic signature peaks at V GSR = 82.1 ± 1.4 km s-1. The observed velocity dispersion of our most probable members is consistent with arising from the velocity uncertainties alone. This indicates that at least along this line of sight, the Orphan Stream is kinematically cold. Our data indicate an overall stream metallicity of [Fe/H] = -1.63 ± 0.19 dex which is more metal-rich than previously found and unbiased by spectral type. Furthermore, the significant metallicity dispersion displayed by our most probable members, σ([Fe/H]) = 0.56 dex, suggests that the unidentified Orphan Stream parent is a dSph satellite. We highlight likely members for high-resolution spectroscopic follow-up.
dc.publisherIOP Publishing
dc.rightsAuthor/s retain copyright
dc.sourceAstrophysical Journal, The
dc.subjectKeywords: galaxies: individual (Orphan Stream); Galaxy: halo; Galaxy: structure; stars: individual (K-giants)
dc.titleHunting the parent of the orphan stream: Identifying stream members from low-resolution spectroscopy
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume764
dc.date.issued2013
local.identifier.absfor020100 - ASTRONOMICAL AND SPACE SCIENCES
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationf5625xPUB2455
local.type.statusPublished Version
local.contributor.affiliationCasey, Andrew, 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.affiliationMaunder, Elizabeth, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.issue39
local.identifier.doi10.1088/0004-637X/764/1/39
dc.date.updated2016-02-24T08:58:37Z
local.identifier.scopusID2-s2.0-84873947041
local.identifier.thomsonID000314335200039
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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