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dc.contributor.authorGu, Meng
dc.contributor.authorConroy, Charlie
dc.contributor.authorLaw, David
dc.contributor.authorvan Dokkum, Pieter
dc.contributor.authorYan, Renbin
dc.contributor.authorWake, David
dc.contributor.authorBundy, Kevin
dc.contributor.authorMerritt, Allison
dc.contributor.authorAbraham, Roberto
dc.contributor.authorZhang, Jielai
dc.contributor.authorBershady, Matthew
dc.contributor.authorBizyaev, Dmitry
dc.contributor.authorBrinkmann, Jonathan
dc.contributor.authorDrory, Niv
dc.contributor.authorGrabowski, Kathleen
dc.contributor.authorMasters, Karen
dc.contributor.authorPan, Kaike
dc.contributor.authorParejko, John
dc.contributor.authorWeijmans, Anne-Marie
dc.contributor.authorZhang, Kai
dc.identifier.citationGu , M , Conroy , C , Law , D , van Dokkum , P , Yan , R , Wake , D , Bundy , K , Merritt , A , Abraham , R , Zhang , J , Bershady , M , Bizyaev , D , Brinkmann , J , Drory , N , Grabowski , K , Masters , K , Pan , K , Parejko , J , Weijmans , A-M & Zhang , K 2018 , ' Low metallicities and old ages for three ultra-diffuse galaxies in the Coma cluster ' , Astrophysical Journal , vol. 859 , 37 .
dc.identifier.otherPURE: 251148048
dc.identifier.otherPURE UUID: 426db7da-b250-484c-9571-ddedf0a0e7ff
dc.identifier.otherBibCode: 2017arXiv170907003G
dc.identifier.otherScopus: 85048014782
dc.identifier.otherORCID: /0000-0002-5908-6852/work/45557832
dc.identifier.otherWOS: 000432876500002
dc.descriptionA.W. acknowledges support of a Leverhulme Trust Early Career Fellowship.en
dc.description.abstractA large population of ultra-diffuse galaxies (UDGs) was recently discovered in the Coma cluster. Here we present optical spectra of three such UDGs, DF 7, DF 44, and DF 17, which have central surface brightnesses of μ g ≈ 24.4–25.1 mag arcsec−2. The spectra were acquired as part of an ancillary program within the SDSS-IV MaNGA Survey. We stacked 19 fibers in the central regions from larger integral field units (IFUs) per source. With over 13.5 hr of on-source integration, we achieved a mean signal-to-noise ratio in the optical of 9.5 Å−1, 7.9 Å−1, and 5.0 Å−1, respectively, for DF 7, DF 44, and DF 17. Stellar population models applied to these spectra enable measurements of recession velocities, ages, and metallicities. The recession velocities of DF 7, DF 44, and DF 17 are ${6599}_{-25}^{+40}$ km s−1, ${6402}_{-39}^{+41}$ km s−1, and ${8315}_{-43}^{+43}$ km s−1, spectroscopically confirming that all of them reside in the Coma cluster. The stellar populations of these three galaxies are old and metal-poor, with ages of ${7.9}_{-2.5}^{+3.6}$ Gyr, ${8.9}_{-3.3}^{+4.3}$ Gyr, and ${9.1}_{-5.5}^{+3.9}$ Gyr, and iron abundances of [Fe/H] $-{1.0}_{-0.4}^{+0.3}$, $-{1.3}_{-0.4}^{+0.4}$, and $-{0.8}_{-0.5}^{+0.5}$, respectively. Their stellar masses are (3–6) × 108M⊙. The UDGs in our sample are as old or older than galaxies at similar stellar mass or velocity dispersion (only DF 44 has an independently measured dispersion). They all follow the well-established stellar mass–stellar metallicity relation, while DF 44 lies below the velocity dispersion-metallicity relation. These results, combined with the fact that UDGs are unusually large for their stellar masses, suggest that stellar mass plays a more important role in setting stellar population properties for these galaxies than either size or surface brightness.
dc.relation.ispartofAstrophysical Journalen
dc.rights© 2018. The American Astronomical Society. All rights reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at:
dc.subjectGalaxies: clusters: individual (Coma)en
dc.subjectGalaxies: evolutionen
dc.subjectGalaxies: stellar contenten
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleLow metallicities and old ages for three ultra-diffuse galaxies in the Coma clusteren
dc.typeJournal articleen
dc.contributor.sponsorThe Leverhulme Trusten
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.contributor.institutionUniversity of St Andrews. Centre for Contemporary Arten
dc.description.statusPeer revieweden

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