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

High-redshift submillimetre galaxies (SMGs) are some of the most rapidlystar-forming galaxies in the Universe. Historically, galaxy formation modelshave had difficulty explaining the observed number counts of SMGs. We combine asemi-empirical model with 3-D hydrodynamical simulations and 3-D dust radiativetransfer to predict the number counts of unlensed SMGs. Because the stellarmass functions, gas and dust masses, and sizes of our galaxies are constrainedto match observations, we can isolate uncertainties related to the dynamicalevolution of galaxy mergers and the dust radiative transfer. The number countsand redshift distributions predicted by our model agree well with observations.Isolated disc galaxies dominate the faint (S_1.1 < ~1 mJy, or S_850 < ~2 mJy)population. The brighter sources are a mix of merger-induced starbursts andgalaxy-pair SMGs; the latter subpopulation accounts for ~30 - 50 per cent ofall SMGs at all S_1.1 > ~0.5 mJy (S_850 > ~1 mJy). The mean redshifts are ~3.0- 3.5, depending on the flux cut, and the brightest sources tend to be athigher redshifts. Because the galaxy-pair SMGs will be resolved into multiplefainter sources by ALMA, the bright ALMA counts should be as much as 2 timesless than those observed using single-dish telescopes. The agreement betweenour model, which uses a Kroupa IMF, and observations suggests that the IMF inhigh-redshifts starbursts need not be top-heavy; if the IMF were top-heavy, ourmodel would over-predict the number counts. We conclude that the difficultysome models have reproducing the observed SMG counts is likely indicative ofmore general problems -- such as an under-prediction of the abundance ofmassive galaxies or a star formation rate--stellar mass relation normalisationlower than that observed -- rather than a problem specific to the SMGpopulation.

Submillimetre galaxies in a hierarchical universe: number counts, redshift distribution, and implications for the IMF