English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present hydrodynamic simulations of the evolution of self-gravitatingdense gas on scales of 1 kiloparsec down to < parsec in a galactic disk,designed to study dense clump formation from giant molecular clouds (GMCs).These structures are expected to be the precursors to star clusters and thisprocess may be the rate limiting step controling star formation rates ingalactic systems as described by the Kennicutt-Schmidt relation. We follow thethermal evolution of the gas down to ~5K using extinction-dependent heating andcooling functions. We do not yet include magnetic fields or localized stellarfeedback, so the evolution of the GMCs and clumps is determined solely byself-gravity balanced by thermal and turbulent pressure support and the largescale galactic shear. While cloud structures and densities change significantlyduring the simulation, GMC virial parameters remain mostly above unity for timescales exceeding the free-fall time of GMCs indicating that energy fromgalactic shear and large-scale cloud motions continuously cascades down to andwithin the GMCs. We implement star formation at a slow, inefficient rate of 2%per local free-fall time, but even this yields global star formation rates thatare about two orders of magnitude larger than the observed Kennicutt-Schmidtrelation due to over-production of dense gas clumps. We expect a combination ofmagnetic support and localized stellar feedback is required to inhibit denseclump formation to ~1% of the rate that results from the nonmagnetic,zero-feedback limit.

Kiloparsec-Scale Simulations of Star Formation in Disk Galaxies. I. The unmagnetized and zero-feedback limit