Time evolution of the galactic relation: the impact of the magnetic field morphology
arXiv:2402.10268 · doi:10.1051/0004-6361/202347606
Abstract
One of the most frequently used indicators to characterize the magnetic field's influence on star formation is the relation between magnetic field strength and gas density ( relation), usually expressed as . The value of is an indication of the dynamical importance of the magnetic field during gas compression. Investigating the global magnetic field's impact on this relation and its evolution, we conduct MHD simulations of Milky-Way-like galaxies including gravity, star formation, and supernova feedback along with non-equilibrium chemistry up to formation fueling star formation. Two initial magnetic field morphologies are studied: one completely ordered (toroidal) and the other completely random. In these models, we study the dynamical importance of the magnetic field through the plasma and the relation. For both magnetic morphologies, low-density regions are thermally supported, while high-density regions are magnetically dominated. Equipartition is reached earlier and at lower densities in the toroidal model. However, the relation is not unique even within the same galaxy, as it consistently includes two different branches for a given density, with ranging from about 0.2 to 0.8. The mean value of for each model also displays significant variations over time, which supersede the differences between the two models. While our findings suggest that the magnetic field morphology does influence the galactic relation, its impact is transient, since time-averaged differences between the models fall within the large temporal scatter. The context and time-dependent nature of the relation underscore the need for comprehensive research and observations to understand the intricate role of magnetic fields in star formation processes across diverse galactic environments.
The paper has been accepted for publication at A&A
References in corpus (26)
- The NumPy array: a structure for efficient numerical computation
- A High Order Godunov Scheme with Constrained Transport and Adaptive Mesh Refinement for Astrophysical MHD
- Inefficient star formation through turbulence, magnetic fields and feedback
- Observational Evidence of Dynamic Star Formation Rate in Milky Way Giant Molecular Clouds
- Magnetohydrodynamic Simulations of Disk Galaxy Formation: the Magnetization of The Cold and Warm Medium
- Deep into the structure of the first galaxies: SERRA views
- The impact of chemistry on the structure of high-z galaxies
- Stochastic star formation in early galaxies: JWST implications
- Moving mesh simulations of star forming cores in magneto-gravo-turbulence
- Non-equilibrium chemistry and cooling in the diffuse interstellar medium - II. Shielded gas
- The Star Formation Rate of the Milky Way as seen by Herschel
- Velocity dispersion in the interstellar medium of early galaxies
- Galactic Dynamos
- How primordial magnetic fields shrink galaxies
- Turbulent dynamo in the two-phase interstellar medium
- Magnetic fields in star formation: a complete compilation of all the DCF estimations
- SDSS-IV MaNGA: Stellar Population Gradients Within Barred Galaxies
- Magnetic Properties of Star-Forming Dense Cores
- Three-dimensional simulations of molecular cloud fragmentation regulated by magnetic fields and ambipolar diffusion
- The impact of magnetic fields on cosmological galaxy mergers. I: Reshaping gas and stellar discs
- Magnetic Fields on FIRE: Comparing B-fields in the multiphase ISM and CGM of Simulated L Galaxies to Observations
- Are the Milky Way and Andromeda unusual? A comparison with Milky Way and Andromeda Analogs
- Shaping the structure of a GMC with radiation and winds
- The impact of magnetic fields on the chemical evolution of the supernova-driven ISM
- Dynamo effect in unstirred self-gravitating turbulence
- The Magnetic Field versus Density relation in Star-Forming Molecular Clouds