Magnetic fields and galactic star formation rates

Journal Article · Tue Feb 10 04:00:00 EST 2015 · Astrophysical Journal Letters

OSTI ID:22364186

Loo, Sven Van ^[1]; Tan, Jonathan C. ^[2]

---

1. School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom)
2. Departments of Astronomy and Physics, University of Florida, Gainesville, FL 32611 (United States)

The regulation of galactic-scale star formation rates (SFRs) is a basic problem for theories of galaxy formation and evolution: which processes are responsible for making observed star formation rates so inefficient compared to maximal rates of gas content divided by dynamical timescale? Here we study the effect of magnetic fields of different strengths on the evolution of giant molecular clouds (GMCs) within a kiloparsec patch of a disk galaxy and resolving scales down to ≃0.5 pc. Including an empirically motivated prescription for star formation from dense gas (n{sub H}>10{sup 5} cm{sup −3}) at an efficiency of 2% per local free-fall time, we derive the amount of suppression of star formation by magnetic fields compared to the nonmagnetized case. We find GMC fragmentation, dense clump formation, and SFR can be significantly affected by the inclusion of magnetic fields, especially in our strongest investigated B-field case of 80 μG. However, our chosen kiloparsec-scale region, extracted from a global galaxy simulation, happens to contain a starbursting cloud complex that is only modestly affected by these magnetic fields and likely requires internal star formation feedback to regulate its SFR.

• OSTI ID: 22364186
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 800; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CLOUDS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
GALACTIC EVOLUTION
GALAXIES
MAGNETIC FIELDS
STAR CLUSTERS
STAR EVOLUTION
STARS