• Login
    View Item 
    •   Home
    • UA Faculty Research
    • UA Faculty Publications
    • View Item
    •   Home
    • UA Faculty Research
    • UA Faculty Publications
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Evidence from the H3 Survey That the Stellar Halo Is Entirely Comprised of Substructure

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Naidu_2020_ApJ_901_48.pdf
    Size:
    10.35Mb
    Format:
    PDF
    Description:
    Final Published Version
    Download
    Author
    Naidu, Rohan P.
    Conroy, Charlie
    Bonaca, Ana
    Johnson, Benjamin D. cc
    Ting, Yuan-Sen
    Caldwell, Nelson cc
    Zaritsky, Dennis
    Cargile, Phillip A.
    Affiliation
    Univ Arizona, Steward Observ
    Issue Date
    2020-09-21
    Keywords
    Galaxy stellar halos
    Galaxy kinematics
    Milky Way evolution
    Galaxy evolution
    Galaxy formation
    Milky Way formation
    Milky Way Galaxy
    Milky Way stellar halo
    
    Metadata
    Show full item record
    Publisher
    IOP PUBLISHING LTD
    Citation
    Naidu, R. P., Conroy, C., Bonaca, A., Johnson, B. D., Ting, Y. S., Caldwell, N., ... & Cargile, P. A. (2020). Evidence from the H3 Survey that the Stellar Halo is Entirely Comprised of Substructure. The Astrophysical Journal, 901(1), 48.
    Journal
    ASTROPHYSICAL JOURNAL
    Rights
    © 2020. The American Astronomical Society. All rights reserved.
    Collection Information
    This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
    Abstract
    In the ΛCDM paradigm, the Galactic stellar halo is predicted to harbor the accreted debris of smaller systems. To identify these systems, the H3 Spectroscopic Survey, combined with Gaia, is gathering 6D phase-space and chemical information in the distant Galaxy. Here we present a comprehensive inventory of structure within 50 kpc from the Galactic center using a sample of 5684 giants at alpha disk, the in situ halo (disk stars heated to eccentric orbits), Sagittarius (Sgr), Gaia-Sausage-Enceladus (GSE), the Helmi Streams, Sequoia, and Thamnos. Additionally, we identify the following new structures: (i) Aleph ([Fe/H] = -0.5), a low-eccentricity structure that rises a surprising 10 kpc off the plane, (ii) and (iii) Arjuna ([Fe/H] = -1.2) and I'itoi ([Fe/H] < -2), which comprise the high-energy retrograde halo along with Sequoia, and (iv) Wukong ([Fe/H] = -1.6), a prograde phase-space overdensity chemically distinct from GSE. For each structure, we provide [Fe/H], [alpha/Fe], and orbital parameters. Stars born within the Galaxy are a major component at<CDATA<i(60%), but their relative fraction declines sharply to less than or similar to 5% past 15 kpc. Beyond 15 kpc, >80% of the halo is built by two massive (M similar to 10(8)-10(9)M) accreted dwarfs: GSE ([Fe/H] = -1.2) within 25 kpc and Sgr ([Fe/H] = -1.0) beyond 25 kpc. This explains the relatively high overall metallicity of the halo ([Fe/H] -1.2). We attribute greater than or similar to 95% of the sample to one of the listed structures, pointing to a halo built entirely from accreted dwarfs and heating of the disk.
    ISSN
    0004-637X
    EISSN
    1538-4357
    DOI
    10.3847/1538-4357/abaef4
    Version
    Final published version
    ae974a485f413a2113503eed53cd6c53
    10.3847/1538-4357/abaef4
    Scopus Count
    Collections
    UA Faculty Publications

    entitlement

     

    Related items

    Showing items related by title, author, creator and subject.

    • Thumbnail

      The Faint End of the Centaurus A Satellite Luminosity Function

      Crnojević, D.; Sand, D. J.; Bennet, P.; Pasetto, S.; Spekkens, K.; Caldwell, N.; Guhathakurta, P.; McLeod, B.; Seth, A.; Simon, J. D.; et al. (IOP PUBLISHING LTD, 2019-02-10)
      The Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) is constructing a wide-field map of the resolved stellar populations in the extended halos of these two nearby, prominent galaxies. We present new Magellan/Megacam imaging of a similar to 3 deg(2) area around Centaurus A (Cen A), which filled in much of our coverage to its south, leaving a nearly complete halo map out to a projected radius of similar to 150 kpc and allowing us to identify two new resolved dwarf galaxies. We have additionally obtained deep Hubble Space Telescope (HST) optical imaging of 11 out of the 13 candidate dwarf galaxies identified around Cen A and presented in Crnojevic et al. 2016a: seven are confirmed to be satellites of Cen A, while four are found to be background galaxies. We derive accurate distances, structural parameters, luminosities, and photometric metallicities for the seven candidates confirmed by our HST/ACS imaging. We further study the stellar population along the similar to 60 kpc long (in projection) stream associated with Dw3, which likely had an initial brightness of M-V similar to -15 and shows evidence for a metallicity gradient along its length. Using the total sample of 11 dwarf satellites discovered by the PISCeS survey, as well as 13 brighter previously known satellites of Cen A, we present a revised galaxy luminosity function for the Cen A group down to a limiting magnitude of M-V similar to -8, which has a slope of -1.14 +/- 0.17, comparable to that seen in the Local Group and in other nearby groups of galaxies.
    • Thumbnail

      Nuclear starburst activity induced by elongated bulges in spiral galaxies

      Kim, Eunbin; Kim, Sungsoo S; Choi, Yun-Young; Lee, Gwang-Ho; de Grijs, Richard; Lee, Myung Gyoon; Hwang, Ho Seong; Univ Arizona, Steward Observ (OXFORD UNIV PRESS, 2018-06-05)
      We study the effects of bulge elongation on the star formation activity in the centres of spiral galaxies using the data from the Sloan Digital Sky Survey Data Release 7. We construct a volume-limited sample of face-on spiral galaxies with Mr < −19.5 mag at 0.02 ≤ z < 0.055 by excluding barred galaxies, where the aperture of the SDSS spectroscopic fibre covers the bulges of the galaxies. We adopt the ellipticity of bulges measured by Simard et al., who performed two-dimensional bulge + disc decompositions using the SDSS images of galaxies, and identify nuclear starbursts using the fibre specific star formation rates derived from the SDSS spectra. We find a statistically significant correlation between bulge elongation and nuclear starbursts in the sense that the fraction of nuclear starbursts increases with bulge elongation. This correlation is more prominent for fainter and redder galaxies, which exhibit higher ratios of elongated bulges. We find no significant environmental dependence of the correlation between bulge elongation and nuclear starbursts. These results suggest that non-axisymmetric bulges can efficiently feed the gas into the centre of galaxies to trigger nuclear starburst activity.
    • Thumbnail

      Exploring the dust content of galactic winds with Herschel – II. Nearby dwarf galaxies

      McCormick, Alexander; Veilleux, Sylvain; Meléndez, Marcio; Martin, Crystal L; Bland-Hawthorn, Joss; Cecil, Gerald; Heitsch, Fabian; Müller, Thomas; Rupke, David S N; Engelbracht, Chad; et al. (OXFORD UNIV PRESS, 2018-06)
      We present the results from an analysis of deep Herschel Space Observatory observations of six nearby dwarf galaxies known to host galactic-scale winds. The superior far-infrared sensitivity and angular resolution of Herschel have allowed detection of cold circumgalactic dust features beyond the stellar components of the host galaxies traced by Spitzer 4.5 mu m images. Comparisons of these cold dust features with ancillary data reveal an imperfect spatial correlation with the ionized gas and warm dust wind components. We find that typically similar to 10-20 per cent of the total dust mass in these galaxies resides outside of their stellar discs, but this fraction reaches similar to 60 per cent in the case of NGC 1569. This galaxy also has the largest metal-licity (O/H) deficit in our sample for its stellar mass. Overall, the small number of objects in our sample precludes drawing strong conclusions on the origin of the circumgalactic dust. We detect no statistically significant trends with star formation properties of the host galaxies, as might be expected if the dust were lifted above the disc by energy inputs from ongoing star formation activity. Although a case for dust entrained in a galactic wind is seen in NGC 1569, in all cases, we cannot rule out the possibility that some of the circumgalactic dust might be associated instead with gas accreted or removed from the disc by recent galaxy interaction events, or that it is part of the outer gas-rich portion of the disc that lies below the sensitivity limit of the Spitzer 4.5 mu m data.
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.