A huge reservoir of ionized gas around the Milky Way: Accounting for the Missing Mass?

  title={A huge reservoir of ionized gas around the Milky Way: Accounting for the Missing Mass?},
  author={Aritra Gupta and Smita Mathur and Yair Krongold and Fabrizio Nicastro and Massimiliano Galeazzi},
  journal={The Astrophysical Journal},
Most of the baryons from galaxies have been "missing" and several studies have attempted to map the circumgalactic medium (CGM) of galaxies in their quest. We report on X-ray observations made with the Chandra X-Ray Observatory probing the warm-hot phase of the CGM of our Milky Way at about 106 K. We detect O VII and O VIII absorption lines at z = 0 in extragalactic sight lines and measure accurate column densities using both Kα and Kβ lines of O VII. We then combine these measurements with the… Expand

Figures and Tables from this paper

The diversity of the circumgalactic medium around z = 0 Milky Way-mass galaxies from the Auriga simulations
Galaxies are surrounded by massive gas reservoirs (i.e. the circumgalactic medium; CGM) which play a key role in their evolution. The properties of the CGM, which are dependent on a variety ofExpand
The Rotation of the Hot Gas Around the Milky Way
The hot gaseous halos of galaxies likely contain a large amount of mass and are an integral part of galaxy formation and evolution. The Milky Way has a 2e6 K halo that is detected in emission and byExpand
Probing the mass and anisotropy of the Milky Way gaseous halo: sight-lines toward Mrk 421 and PKS 2155-304
We recently found that the halo of the Milky Way contains a large reservoir of warm-hot gas that accounts for large fraction of the missing baryons from the Galaxy. The average physical properties ofExpand
X-ray detection of warm ionized matter in the Galactic halo
We report on a systematic investigation of the cold and mildly ionized gaseous baryonic metal components of our Galaxy, through the analysis of high resolution Chandra and XMM-Newton spectra of twoExpand
Hot gas in Milky Way size galaxies at z=0
Abstract We present a new set of cosmological Milky Way size galaxy simulations using ART. In our simulations the main system has been evolved inside a 28 Mpc cosmological box with a spatialExpand
Density and metallicity of the Milky Way circumgalactic gas
The halo of the Milky-Way circumgalactic gas extends up to the virial radius of the Galaxy, ~250 kpc. The halo properties may be deduced from X-ray spectroscopic observations and from studies of theExpand
Strategies for detecting the missing hot baryons in the universe
Abstract. About 30% to 50% of the baryons in the local universe are unaccounted for and are likely in a hot phase, 105.5 to 108 K. A hot halo (106.3 K) is detected around the Milky Way through the OExpand
The Origin of the Hot Gas in the Galactic Halo: Testing Galactic Fountain Models' X-Ray Emission
We test the X-ray emission predictions of galactic fountain models against XMM-Newton measurements of the emission from the Milky Way's hot halo. These measurements are from 110 sight lines, spanningExpand
The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-redshift Circumgalactic Medium
We analyze the physical conditions of the cool, photoionized (T ∼ 10 4 K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density measurements for 44 gaseous halos within 160 kpcExpand
The Mass Profile of the Milky Way to the Virial Radius from the Illustris Simulation
We use particle data from the Illustris simulation, combined with individual kinematic constraints on the mass of the Milky Way (MW) at specific distances from the Galactic Centre, to infer theExpand


X-Ray Absorption from the Milky Way Halo and the Local Group
Million degree gas is present at near-zero redshift and is due to either a gaseous Galactic halo or a more diffuse but very massive Local Group medium. We can discriminate between these modelsExpand
A Galactic Origin for the Local Ionized X-Ray Absorbers
Recent Chandra and XMM-Newton observations of distant quasars have shown strong local (z ~ 0) X-ray absorption lines from highly ionized gas, primarily He-like oxygen. The nature of these X-rayExpand
X-Ray Absorption by the Low-Redshift Intergalactic Medium: A Numerical Study of the Λ Cold Dark Matter Model
Using a hydrodynamic simulation of a cold dark matter universe with a cosmological constant, we investigate the "X-ray forest" absorption imprinted on the spectra of background quasars by theExpand
MAGICC haloes: confronting simulations with observations of the circumgalactic medium at z = 0
We explore the circumgalactic medium (CGM) of two simulated star-forming galaxies with luminosities L ≈ 0.1 and 1 L⋆ generated using the smooth particle hydrodynamic code gasoline. These simulationsExpand
Do Hot Halos Around Galaxies Contain the Missing Baryons
Galaxies are missing most of their baryons, and many models predict these baryons lie in a hot halo around galaxies. We establish observationally motivated constraints on the mass and radii of theseExpand
The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations
We compare the predictions of three physical models for the origin of the hot halo gas with the observed halo X-ray emission, derived from 26 high-latitude XMM-Newton observations of the soft X-rayExpand
We present a high-resolution (λ/Δλ ≈ 500) X-ray spectrum of the bright quasar H1821+643 (z = 0.297), obtained in a 470 ks observation with the Chandra X-Ray Observatory. We search for X-rayExpand
Interactions of cosmic rays with the interstellar medium in the disk of the Milky Way provide the majority of the diffuse gamma-ray emission observed by the Fermi Gamma-ray Space Telescope. InExpand
XMM-Newton Observations of the Diffuse X-Ray Background
We analyze two XMM-Newton observations toward the high-density, high-latitude, neutral hydrogen cloud MBM 20 and a nearby low-density region that we call the Eridanus hole. MBM 20 lies at a distanceExpand
Chandra and Far Ultraviolet Spectroscopic Explorer Observations of z ~ 0 Warm-Hot Gas toward PKS 2155–304
The X-ray-bright z = 0.116 quasar PKS 2155-304 is frequently observed as a Chandra calibration source, with a total of 483 ks of Low Energy Transmission Grating (LETG) exposure time accumulatedExpand