The Magellanic Corona and the formation of the Magellanic Stream

Abstract

The dominant gaseous structure in the Galactic halo is the Magellanic Stream, an extended network of neutral and ionized filaments surrounding the Large and Small Magellanic Clouds (LMC/SMC), the two most massive satellite galaxies of the Milky Way. Recent observations indicate that the Clouds are on their first passage around our Galaxy, the Stream is made up of gas stripped from both the LMC and the SMC, and the majority of this gas is ionized. While it has long been suspected that tidal forces and ram-pressure stripping contributed to the Stream's formation, a full understanding of its origins has defied modelers for decades. Several recent developments, including the discovery of dwarf galaxies associated with the Magellanic Group, the high mass of the LMC, the detection of highly ionized gas toward stars in the LMC and the predictions of cosmological simulations all support the existence of a halo of warm ionized gas around the LMC at a temperature of $\sim 5\times 10^5\mathrm{K}$. Here we show that by including this "Magellanic Corona" in hydrodynamic simulations of the Magellanic Clouds falling onto the Galaxy, we can simultaneously reproduce the Stream and its Leading Arm. Our simulations explain the Stream's filamentary structure, spatial extent, radial velocity gradient, and total ionized gas mass. We predict that the Magellanic Corona will be unambiguously observable via high-ionization absorption lines in the ultraviolet spectra of background quasars lying near the LMC. This prediction is directly testable with the Cosmic Origins Spectrograph on the Hubble Space Telescope.

32 pages, 7 figures. Published in the September 20 issue of Nature. This is the authors' version before final edits. Published version is available at https://www.nature.com/articles/s41586-020-2663-4

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Cited by in corpus (35)

• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• Detection of the Keplerian decline in the Milky Way rotation curve
• The effect of the LMC on the Milky Way system
• The Magellanic Stream at 20 kpc: A New Orbital History for the Magellanic Clouds
• Observations of a Magellanic Corona
• 3D hydrodynamic simulations for the formation of the Local Group satellite planes
• Discovery of the Magellanic Stellar Stream Out to 100 Kiloparsecs
• The effects of LMC-mass environments on their dwarf satellite galaxies in the FIRE simulations
• The hot circumgalactic media of massive cluster satellites in the TNG-Cluster simulation: existence and detectability
• Cold and Hot gas distribution around the Milky-Way-M31 system in the HESTIA simulations
• The Large Magellanic Cloud Revealed in Gravitational Waves with LISA
• Characterizing the Circumgalactic Medium of the Lowest-Mass Galaxies: A Case Study of IC 1613
• It's a Breeze: The Circumgalactic Medium of a Dwarf Galaxy is Easy to Strip
• Radiative Turbulent Mixing Layers and the Survival of Magellanic Debris
• Properties of the Magellanic Corona
• The Relevance of Dynamical Friction for the MW/LMC/SMC Triple System
• Ram pressure stripping in clusters: Gravity can bind the ISM but not the CGM
• Lessons from the Magellanic System and its modeling
• UVIT Study of the MAgellanic Clouds (U-SMAC) II. A Far-UV catalog of the Small Magellanic Cloud: Morphology and Kinematics of young stellar population
• The Magellanic Clouds are very rare in the IllustrisTNG simulations
• Revisiting newly Large Magellanic Cloud age gap star clusters
• The Magellanic Puzzle: origin of the periphery
• Galaxies at a Cosmic-Ray Eddington Limit
• Investigating the Baryon Cycle in Interacting Dwarfs with the Very Large Array and Pan-STARRS
• The Diffuse Ionized Gas of the Large Magellanic Cloud
• The VMC survey -- LIV. The internal kinematics of the LMC with new VISTA observations
• UVIT Study of the MAgellanic Clouds (U-SMAC) I. Recent star formation history and kinematics of the Shell region in the North-Eastern Small Magellanic Cloud
• Following the tidal trail: a history of modeling the Magellanic Stream
• The Evolution of Magellanic-like Galaxy Pairs and The Production of Magellanic Stream Analogues in Simulations with Tides, Ram Pressure, and Stellar Feedback
• Discovery of the Goat Horn complex: a $\sim 1000$ deg${}^2$ diffuse X-ray source connected to radio loop XII
• Distant probes of RM structure -- Where is the Faraday Rotation towards the Magellanic Leading Arm?
• A neutral hydrogen absorption study of cold gas in the outskirts of the Magellanic Clouds using the GASKAP-HI survey
• Wind of Change: Faraday Rotation in a Simulated Large Magellanic Cloud
• Threading the Magellanic Needle: Hypervelocity Stars Trace the Past Location of the LMC
• Mapping the Distorted Dark Matter Distribution of the LMC-SMC System Prior to Milky Way Infall with Basis Function Expansions