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dc.contributor.authorMeisner, Aaron M.
dc.contributor.authorJurić, Mario
dc.contributor.authorFinkbeiner, Douglas P.
dc.contributor.authorFrebel, Anna L.
dc.date.accessioned2015-02-19T21:21:29Z
dc.date.available2015-02-19T21:21:29Z
dc.date.issued2012-06
dc.date.submitted2011-12
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://hdl.handle.net/1721.1/95428
dc.description.abstractWe present low-resolution MMT Hectospec spectroscopy of 594 candidate Monoceros stream member stars. Based on strong color-magnitude diagram overdensities, we targeted three fields within the stream's footprint, with 178° ≤ l ≤ 203° and –25° ≤ b ≤ 25°. By comparing the measured iron abundances with those expected from smooth Galactic components alone, we measure, for the first time, the spectroscopic metallicity distribution function for Monoceros. We find the stream to be chemically distinct from both the thick disk and halo, with [Fe/H] = –1, and do not detect a trend in the stream's metallicity with Galactic longitude. Passing from b = +25° to b = –25°, the median Monoceros metallicity trends upward by 0.1 dex, though uncertainties in modeling sample contamination by the disk and halo make this a marginal detection. In each field, we find Monoceros to have an intrinsic [Fe/H] dispersion of 0.10-0.22 dex. From the Ca II K line, we measure [Ca/Fe] for a subsample of metal-poor program stars with –1.1 < [Fe/H] < –0.5. In two of three fields, we find calcium deficiencies qualitatively similar to previously reported [Ti/Fe] underabundances in Monoceros and the Sagittarius tidal stream. Further, using 90 spectra of thick disk stars in the Monoceros pointings with b ≈ ±25°, we detect a 0.22 dex north/south metallicity asymmetry coincident with known stellar density asymmetry at R [subscript GC] ≈ 12 kpc and |Z| ≈ 1.7 kpc. Our median Monoceros [Fe/H] = –1.0 and its relatively low dispersion naturally fit the expectation for an appropriately luminous M[subscript V] ~ – 13 dwarf galaxy progenitor.en_US
dc.description.sponsorshipSmithsonian Astrophysical Observatory (Clay Fellowship)en_US
dc.language.isoen_US
dc.publisherIOP Publishingen_US
dc.relation.isversionofhttp://dx.doi.org/10.1088/0004-637x/753/2/116en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Astronomical Societyen_US
dc.titleTHE METALLICITY OF THE MONOCEROS STREAMen_US
dc.typeArticleen_US
dc.identifier.citationMeisner, Aaron M., Anna Frebel, Mario Jurić, and Douglas P. Finkbeiner. “THE METALLICITY OF THE MONOCEROS STREAM.” The Astrophysical Journal 753, no. 2 (June 20, 2012): 116. © 2012 The American Astronomical Societyen_US
dc.contributor.departmentKavli Institute for Astrophysics and Space Researchen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Physicsen_US
dc.contributor.mitauthorFrebel, Anna L.en_US
dc.relation.journalAstrophysical Journalen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsMeisner, Aaron M.; Frebel, Anna; Jurić, Mario; Finkbeiner, Douglas P.en_US
dc.identifier.orcidhttps://orcid.org/0000-0002-2139-7145
mit.licensePUBLISHER_POLICYen_US


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