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Cited by 273Galaxies: Formation, Evolution, PhenomenaAstrophysical Phenomena and ObservationsStellar, planetary, and galactic studies

CONSTRAINING THE MILKY WAY'S HOT GAS HALO WITH O VII AND O VIII EMISSION LINES

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Miller, Matthew J., Bregman, Joel N.·2015·The Astrophysical Journal
DOI 10.1088/0004-637x/800/1/14
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Abstract

The Milky Way hosts a hot (≈2 × 10 6 K), diffuse, gaseous halo based on detections of z = 0 O vii and O viii absorption lines in quasar spectra and emission lines in blank-sky spectra. Here we improve constraints on the structure of the hot gas halo by fitting a radial model to a much larger sample of O vii and O viii emission line measurements from XMM-Newton /EPIC-MOS spectra compared to previous studies (≈650 sightlines). We assume a modified β-model for the halo density distribution and a constant-density Local Bubble from which we calculate emission to compare with the observations. We find an acceptable fit to the O viii emission line observations with (dof) = 1.08 (644) for best-fit parameters of cm −3 kpc 3β and β = 0.50 ± 0.03 for the hot gas halo and negligible Local Bubble contribution. The O vii observations yield an unacceptable (dof) = 4.69 (645) for similar best-fit parameters, which is likely due to temperature or density variations in the Local Bubble. The O viii fitting results imply hot gas masses of M (<50 kpc) = and M (<250 kpc) = , accounting for ≲50% of the Milky Way's missing baryons. We also explore our results in the context of optical depth effects in the halo gas, the halo gas cooling properties, temperature and entropy gradients in the halo gas, and the gas metallicity distribution. The combination of absorption and emission line analyses implies a sub-solar gas metallicity that decreases with radius, but that also must be ⩾0.3 Z ☉ to be consistent with the pulsar dispersion measure toward the Large Magellanic Cloud.

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105 of 105 references verified0 citation errors · 0 not checkable

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Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The Galactic circumgalactic medium extends to approximately 200 kpc.

    “the Galactic CGM extends till ∼ 200 kpc”

    From The Fermi/eROSITA bubbles: a look into the nuclear outflow from the Milky Way (2024) · cites this paper as Miller & Bregman 2015

    Section 5.1 (page unavailable) adopts a Milky Way virial radius of 250 kpc and estimates hot-gas mass within it, which supports a halo scale of roughly 200 kpc. But the paper says “if” its fitted hot-gas density profile extends to that radius; it does not establish an outer edge at approximately 200 kpc, as the citing sentence implies. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • The absorbing medium toward the NPS has a temperature of 0.17-0.2 keV and a column density of 3-5 × 10^19 cm^-2.

    “The absorbing medium is characterized to have a temperature of 0 . 17 -0 . 2 keV (similar to the Galactic CGM; Henley &amp; Shelton 2010; Miller &amp; Bregman 2015) and a column density of 3 -5 × 10 19 cm 2 .”

    From The Fermi/eROSITA bubbles: a look into the nuclear outflow from the Milky Way (2024) · cites this paper as Miller & Bregman 2015

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Research works printed but not linked: 5

  1. Asplund, M., Grevesse, N., & Sauval, A. J. 2005, in ASP Conf. Ser. 336, Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis, ed. T. G. Barnes, III & F. N. Bash (San Francisco, CA: ASP), 25
  2. Binney, J., & Tremaine, S. 2008, Galactic Dynamics (2nd ed.; Princeton, NJ: Princeton Univ. Press)
  3. Holweger, H. 2001, in AIP Conf. Proc. 598, Joint SOHO/ACE Workshop Solar and Galactic Composition, ed. R. F. Wimmer-Schweingruber (Melville, NY: AIP), 23
  4. Rasmussen, A., Kahn, S. M., & Paerels, F. 2003, in The IGM/Galaxy Connection, The Distribution of Baryons at z=0, ed. J. L. Rosenberg & M. E. Putman (Astrophysics and Space Science Library, Vol. 281; Dordrecht: Kluwer), 109
  5. Wang, Q. D. 1998, in IAU Colloq. 166: The Local Bubble and Beyond, ed. D. Breitschwerdt, M. J. Freyberg, & J. Truemper (Lecture Notes in Physics, Vol. 506; Berlin: Springer), 503

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Authors
Miller, M. J., & Bregman, J. N.
Affiliations
University of Michigan (US)
ORCID
Bregman, Joel N.
Venue
The Astrophysical Journal
Publisher
American Astronomical Society
Published
2015-02-04
Volume
800
Issue
1
Pages
14
ISSN
  • 0004-637X (ISSN-L)
  • 1538-4357
DOI
10.1088/0004-637x/800/1/14
OpenAlex
W2002520353
Cited by
273
References
103
Citations by year
2026: 18 · 2025: 21 · 2024: 21 · 2023: 20 · 2022: 26 · 2021: 18 · 2020: 31 · 2019: 22 · 2018: 35 · 2017: 21 · 2016: 26 · 2015: 14
FWCI
18.22
Type
journal article
Language
en
Open access
Licence
Locations
  • The Astrophysical Journal (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • arXiv (Cornell University)
Funders
National Aeronautics and Space Administration (NNX11AJ55G)
Topics
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Astrophysical Phenomena and Observations
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Stellar, planetary, and galactic studies
Keywords
missing baryons, Local Bubble, quasar absorption lines, X-ray emission lines, optical depth effects, gas cooling, entropy gradients, pulsar dispersion measure, Large Magellanic Cloud

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