A disk-dominated and clumpy circumgalactic medium of the Milky Way seen in X-ray emission

Abstract

The Milky Way galaxy is surrounded by a circumgalactic medium (CGM) that may play a key role in galaxy evolution as the source of gas for star formation and a repository of metals and energy produced by star formation and nuclear activity. The CGM may also be a repository for baryons seen in the early universe, but undetected locally. The CGM has an ionized component at temperatures near $2\times 10^6$~K studied primarily in the soft X-ray band. Here we report a survey of the southern Galactic sky with a soft X-ray spectrometer optimized to study diffuse soft X-ray emission. The X-ray emission is best fit with a disc-like model based on the radial profile of the surface density of molecular hydrogen, a tracer of star formation, suggesting that the X-ray emission is predominantly from hot plasma produced via stellar feedback. Strong variations in the X-ray emission on angular scales of $\sim 10^{\circ }$ indicate that the CGM is clumpy. Addition of an extended, and possibly massive, halo component is needed to match the halo density inferred from other observations.

Published in Nature Astronomy, 18 pages

References in corpus (9)

• The Circumgalactic Medium
• Constraining the Milky Way's Hot Gas Halo with OVII and OVII Emission Lines
• Vertical structure of a supernova-driven turbulent magnetized ISM
• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Charge-Transfer induced EUV and Soft X-ray emissions in the Heliosphere
• The Chandra COSMOS legacy survey: Energy Spectrum of the Cosmic X-ray Background and constraints on undetected populations
• OVII and OVIII line emission in the diffuse soft X-ray background: heliospheric and galactic contributions
• The Structure of the Local Hot Bubble
• HaloSat -- A CubeSat to Study the Hot Galactic Halo

Cited by in corpus (31)

• A nearby repeating fast radio burst in the direction of M81
• A Local Universe Host for the Repeating Fast Radio Burst FRB 20181030A
• An FRB Sent Me a DM: Constraining the Electron Column of the Milky Way Halo with Fast Radio Burst Dispersion Measures from CHIME/FRB
• The Circumgalactic Medium of Milky Way-like Galaxies in the TNG50 Simulation -- I: Halo Gas Properties and the Role of SMBH Feedback
• Abundance and temperature of the outer hot circum-Galactic medium: The SRG/eROSITA view of the soft X-ray background in the eFEDS field
• The hot circumgalactic medium of the Milky Way: evidence for super-virial, virial, and sub-virial temperature, non-solar chemical composition, and non-thermal line broadening
• Widespread Detection of Two Components in the Hot Circumgalactic Medium of the Milky Way
• Cloud-by-cloud, multiphase, Bayesian modeling: Application to four weak, low ionization absorbers
• The warm-hot circumgalactic medium of the Milky Way as seen by eROSITA
• Detection of thermal Sunyaev-Zel'dovich Effect in the circumgalactic medium of low-mass galaxies -- a surprising pattern in self-similarity and baryon sufficiency
• The hot circumgalactic medium of the Milky-Way: new insights from XMM-Newton observations
• The SRG/eROSITA diffuse soft X-ray background. I. The local hot bubble in the western Galactic hemisphere
• Galactic coronae in Milky Way-like galaxies: the role of stellar feedback in gas accretion
• An X-ray and SZ bright diffuse source toward M31: a Local Hot Bridge
• A deep, multi-epoch Chandra HETG study of the ionized outflow from NGC 4051
• The Solar-Cycle Temporal Variation of the Solar Wind Charge Exchange X-ray Lines
• The soft X-ray background with Suzaku: I. Milky Way halo
• A Search for the 3.5 keV Line from the Milky Way's Dark Matter Halo with HaloSat
• A HaloSat Analysis of the Cygnus Superbubble
• Quantifying Observational Projection Effects with a Simulation-based hot CGM model
• On the patchy appearance of the circum-Galactic medium and the influence of foreground absorption
• The Warm Gas in the MW: the Kinematical Model of C IV and its Connection with Si IV
• On the origin of the $10^7$ K hot emitting gas in the Circumgalactic medium of the Milky Way
• Strong Evidence for Cosmic Ray-Supported $\sim$L${}^{\ast }$ Galaxy Halos via X-ray \& tSZ Constraints
• Constraining the Milky Way's Dispersion Measure Using FRB and X-ray Data
• Modeling of geocoronal solar wind charge exchange events detected with Suzaku
• On the baryon budget in the X-ray-emitting circumgalactic medium of Milky Way-mass galaxies
• Bayesian Modeling of NICER Cometary X-ray Spectra: A Legacy Survey of Solar-Wind Charge Exchange
• Constraints on cosmic rays in the Milky Way circumgalactic medium from OVIII observations
• The HaloSat and PolarLight CubeSat Missions for X-ray Astrophysics
• Prospects for studying million-degree gas in the Milky Way halo using the forbidden optical [FeX] and [FeXIV] intersystem lines