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

Understanding the rate at which stars form is central to studies of galaxyformation. Observationally, the star formation rates (SFRs) of galaxies aremeasured using the luminosity in different frequency bands, often under theassumption of a time-steady SFR in the recent past. We use star formationhistories (SFHs) extracted from cosmological simulations of star-forminggalaxies from the FIRE project to analyze the time-scales to which theH${\alpha}$ and far-ultraviolet (FUV) continuum SFR indicators are sensitive.In these simulations, the SFRs are highly time variable for all galaxies athigh redshift, and continue to be bursty to z=0 in dwarf galaxies. When FIRESFHs are partitioned into their bursty and time-steady phases, the best-fittingFUV time-scale fluctuates from its ~10 Myr value when the SFR is time-steady to>~100 Myr immediately following particularly extreme bursts of star formationduring the bursty phase. On the other hand, the best-fitting averagingtime-scale for H${\alpha}$ is generally insensitive to the SFR variability inthe FIRE simulations and remains ~5 Myr at all times. These time-scales areshorter than the 100 Myr and 10 Myr time-scales sometimes assumed in theliterature for FUV and H${\alpha}$, respectively, because while the FUVemission persists for stellar populations older than 100 Myr, thetime-dependent luminosities are strongly dominated by younger stars. Ourresults confirm that the ratio of SFRs inferred using H${\alpha}$ vs. FUV canbe used to probe the burstiness of star formation in galaxies.

The time-scales probed by star formation rate indicators for realistic, bursty star formation histories from the FIRE simulations