Not gone with the Wind: Survival of High-Velocity Molecular Clouds in the Galactic center

Abstract

High-velocity atomic clouds in the Galactic center have attracted significant attention due to their enigmatic formation process, which is potentially linked to the starburst or supermassive black hole activities in the region. Further, the discovery of high-velocity molecular clouds (HVMCs) presents a greater puzzle, because they are much denser and more massive. If the HVMCs were accelerated by the strong activities in the Galactic center, they are expected to be destroyed before they reach such a high velocity. To shed light on this phenomenon, we perform three-dimensional numerical simulations to investigate the origin and hydrodynamic evolution of HVMCs during a starburst in the Galactic center. We find that the presence of a magnetic field provides effective protection and acceleration to molecular clouds (MCs) within the galactic winds. Consequently, the MCs can attain latitudes of approximately 1 kpc with velocities around 200 km/s, consistent with the observed characteristics of HVMCs. The consistency of our findings across a wide parameter space supports the conclusion that HVMCs can indeed withstand the starburst environment in the Galactic center, providing valuable insights into their survival mechanisms.

18 pages, 16 figures, submitted to MNRAS

References in corpus (38)

• PLUTO: a Numerical Code for Computational Astrophysics
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Momentum Injection by Supernovae in the Interstellar Medium
• The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays
• Draping of Cluster Magnetic Fields over Bullets and Bubbles -- Morphology and Dynamic Effects
• Detection of large-scale X-ray bubbles in the Milky Way halo
• Magnetized Gas Clouds can Survive Acceleration by a Hot Wind
• Giant Magnetized Outflows from the Centre of the Milky Way
• The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass
• Photodissociation and X-Ray Dominated Regions
• Hydrodynamical Coupling of Mass and Momentum in Multiphase Galactic Winds
• The Galactic Centre Chimney
• Probing the Fermi Bubbles in Ultraviolet Absorption: A Spectroscopic Signature of the Milky Way's Biconical Nuclear Outflow
• Fermi Bubbles Inflated by Winds Launched from the Hot Accretion Flow in Sgr A*
• Nuclear Outflow of the Milky Way: Studying the Kinematics and Spatial Extent of the Northern Fermi Bubble
• The Central 300 pc of the Galaxy probed by infrared spectra of H${}_3^{+}$ and CO: part I. Predominance of warm and diffuse gas and high H${}_2$ ionization rate
• Models of irradiated molecular shocks
• Fermi and eRosita bubbles as relics of the past activity of the Galactic black hole
• A signature of anisotropic cosmic-ray transport in the gamma-ray sky
• Cold gas in the Milky Way's nuclear wind
• The Galactic center chimneys: The base of the multiphase outflow of the Milky Way
• Simple Yet Powerful: Hot Galactic Outflows Driven by Supernovae
• Outflows in Star-forming Galaxies: Stacking Analyses of Resolved Winds and the Relation to Their Hosts' Properties
• The Spatially Uniform Spectrum of the Fermi Bubbles: the Leptonic AGN Jet Scenario
• Intermediate- and high-velocity clouds in the Milky Way I: covering factors and vertical heights
• Simulating the Fermi Bubbles as Forward Shocks Driven by AGN Jets
• Intermediate- and high-velocity clouds in the Milky Way II: evidence for a Galactic fountain with collimated outflows and diffuse inflows
• Frequency and nature of central molecular outflows in nearby star-forming disk galaxies
• Observation of Acceleration of HI Clouds Within the Fermi Bubbles
• Mapping Outflowing Gas in the Fermi Bubbles: a UV Absorption Survey of the Galactic Nuclear Wind
• A Hadronic-Leptonic Model for the Fermi Bubbles: Cosmic-Rays in the Galactic Halo and Radio Emission
• Numerical Simulations of a Shock Interacting with Multiple Magnetized Clouds
• Interstellar Extinction and Elemental Abundances
• Molecular Gas within the Milky Way's Nuclear Wind
• Molecular Outflows in z > 6 QSO Hosts Driven by Star Formation
• Magnetic field draping around clumpy high-velocity clouds in galactic halo
• Diverse metallicities of Fermi bubble clouds indicate dual origins in the disk and halo