The Magellanic Stream at 20 kpc: A New Orbital History for the Magellanic Clouds

Abstract

We present new simulations of the formation of the Magellanic Stream based on an updated first-passage interaction history for the Magellanic Clouds, including both the Galactic and Magellanic Coronae and a live dark matter halo for the Milky Way. This new interaction history is needed because previously successful orbits need updating to account for the Magellanic Corona and the loosely bound nature of the Magellanic Group. These orbits involve two tidal interactions over the last 3.5 Gyrs and reproduce the Stream's position and appearance on the sky, mass distribution, and velocity profile. Most importantly, our simulated Stream is only $\sim$20 kpc away from the Sun at its closest point, whereas previous first-infall models predicted a distance of $100-200$ kpc. This dramatic paradigm shift in the Stream's 3D position would have several important implications. First, estimates of the observed neutral and ionized masses would be reduced by a factor of $\sim$5. Second, the stellar component of the Stream is also predicted to be $<$20 kpc away. Third, the enhanced interactions with the MW's hot corona at this small distance would substantially shorten the Stream's lifetime. Finally, the MW's UV radiation field would be much stronger, potentially explaining the H$\alpha$ emission observed along most of the Stream. Our prediction of a 20 kpc Stream could be tested by searching for UV absorption lines towards distant MW halo stars projected onto the Stream.

arXiv comment11 pages, 4 figures. Published in ApJL at https://iopscience.iop.org/article/10.3847/2041-8213/ac3338. Movies and interactive figures available at https://github.com/DOnghiaGroup/lucchini-2021-movies

References in corpus (58)

• The cosmological simulation code GADGET-2
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Cosmological SPH simulations: A hybrid multi-phase model for star formation
• Modeling feedback from stars and black holes in galaxy mergers
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• GIZMO: A New Class of Accurate, Mesh-Free Hydrodynamic Simulation Methods
• FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation
• New Understanding of Large Magellanic Cloud Structure, Dynamics and Orbit from Carbon Star Kinematics
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• Third-Epoch Magellanic Cloud Proper Motions I: HST/WFC3 data and Orbit Implications
• GASS: The Parkes Galactic All-Sky Survey. I. Survey Description, Goals, and Initial Data Release
• The Role of Dwarf Galaxy Interactions in Shaping the Magellanic System and Implications for Magellanic Irregulars
• The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream
• N-body Simulations of the Small Magellanic Cloud and the Magellanic Stream
• The disruption of nearby galaxies by the Milky Way
• The Parkes HI Survey of the Magellanic System
• Cosmological simulations of the circumgalactic medium with 1 kpc resolution: enhanced HI column densities
• A timing constraint on the (total) mass of the Large Magellanic Cloud
• Do Hot Haloes Around Galaxies Contain the Missing Baryons?
• The Origin of the Magellanic Stream
• The Tidal Origin of the Magellanic Stream and the Possibility of a Stellar Counterpart
• Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud
• The Origins of the Circumgalactic Medium in the FIRE Simulations
• Small Dwarf Galaxies Within Larger Dwarfs: Why Some Are Luminous While Most Go Dark
• The 200 Degree-Long Magellanic Stream System
• The Magellanic Stream: Circumnavigating the Galaxy
• The COS/UVES Absorption Survey of the Magellanic Stream. III: Ionization, Total Mass, and Inflow Rate onto the Milky Way
• Spectroscopic Survey of Red Giants in the SMC. I: Kinematics
• A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star Formation in the Milky Way
• Ram Pressure Stripping of the Large Magellanic Cloud's Disk as a Probe of the Milky Way's Circumgalactic Medium
• The Source of Ionization along the Magellanic Stream
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• The Proper Motion Field of the Small Magellanic Cloud: Kinematic Evidence for its Tidal Disruption
• The Magellanic Stream System: I. Ram-pressure tails and the relics of the collision between the Magellanic Clouds
• Fossil imprint of a powerful flare at the Galactic Centre along the Magellanic Stream
• Constraining the orbital history of the Magellanic Clouds: A new bound scenario suggested by the tidal origin of the Magellanic Stream
• The large-scale ionization cones in the Galaxy
• The Magellanic Corona and the formation of the Magellanic Stream
• The Magellanic Stream and the density of coronal gas in the Galactic halo
• Toward a Complete Understanding of the Magellanic Stream Formation
• Models of Tidally Induced Gas Filaments in the Magellanic Stream
• An Interaction of a Magellanic Leading Arm High Velocity Cloud with the Milky Way Disk
• Accretion of the Magellanic system onto the Galaxy
• A Genetic Approach to the History of the Magellanic Clouds
• Trojans in the Solar Neighborhood
• The Properties of the Galactic Hot Gaseous Halo from X-ray Emission
• The Magellanic Stream: break up and accretion onto the hot Galactic corona
• The Magellanic System: the puzzle of the leading gas stream
• Lyman-αabsorption beyond the disk of simulated spiral galaxies
• Chemical Abundances in the Leading Arm of the Magellanic Stream
• Rotation of the Milky Way and the formation of the Magellanic Stream
• Discovery of a disrupting open cluster far into the Milky Way halo: a recent star formation event in the leading arm of the Magellanic stream?
• The Magellanic Stream and Debris Clouds
• Revealing the Ionization Properties of the Magellanic Stream using Optical Emission
• Kinematics of the Magellanic Stream and Implications for its Ionization
• Discovery of Magellanic Stellar Debris in the H3 Survey
• H$\alpha$ Distances to the Leading Arm of the Magellanic Stream

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• Radiative Turbulent Mixing Layers and the Survival of Magellanic Debris
• Structural and Dynamical Analysis of the Quiescent Molecular Ridge in the Large Magellanic Cloud
• The signature of large scale turbulence driving on the structure of the interstellar medium
• A Tilt in the Dark Matter Halo of the Galaxy
• The orbital dynamics of the LMC and SMC about the Milky Way