Physical properties and evolution of (sub-)millimetre-selected galaxies in the galaxy formation simulation shark

Claudia Del P. Lagos, Elisabete Da Cunha, Aaron S.G. Robotham, Danail Obreschkow, Francesco Valentino, Seiji Fujimoto, Georgios E. Magdis, Rodrigo Tobar

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We thoroughly explore the properties of (sub)-millimetre (mm) selected galaxies (SMGs) in the shark semi-analytic model of galaxy formation. Compared to observations, the predicted number counts at wavelengths (λ) 0.6-2 mm and redshift distributions at 0.1-2 mm, agree well. At the bright end (≥1 mJy), shark galaxies are a mix of mergers and disc instabilities. These galaxies display a stacked far-ultraviolet (FUV)-to-far-infrared (FIR) spectrum that agrees well with observations. We predict that current optical/NIR surveys are deep enough to detect bright (>1 mJy) λ = 0.85-2 mm-selected galaxies at z ≲ 5, but too shallow to detect counterparts at higher redshift. A James Webb Space Telescope 10 000s survey should detect all counterparts for galaxies with S0.85mm ≳ 0.01 mJy. We predict SMG's disks contribute significantly (negligibly) to the rest-frame UV (IR). We investigate the 0 ≤ z ≤ 6 evolution of the intrinsic properties of >1 mJy λ = 0.85-2 mm-selected galaxies finding their: (i) stellar masses are > 1010.2, M⊙, with the 2 mm ones tracing the most massive galaxies (> 1011 M⊙); (ii) specific star formation rates (SFR) are mildly (≈3-10 times) above the main sequence (MS); (iii) host halo masses are > 1012.3, M⊙, with 2 mm galaxies tracing the most massive haloes (protoclusters); (iv) SMGs have lower dust masses (≈ 108 M⊙), higher dust temperatures (≈40-45 K) and higher rest-frame V-band attenuation (>1.5) than MS galaxies; (v) sizes decrease with redshift, from 4 kpc at z = 1 to ≲1 kpc at z = 4; and (vi) the carbon monoxide line spectra of S0.85mm ≳ 1 mJy sources peak at 4 → 3. Finally, we study the contribution of SMGs to the molecular gas and cosmic SFR density at 0 ≤ z ≤ 10, finding that >1 mJy sources make a negligible contribution at z ≳ 3 and 5, respectively, suggesting current observations have unveiled the majority of the SF at 0 ≤ z ≤ 10.

Original languageEnglish
Pages (from-to)1948-1971
Number of pages24
JournalMonthly Notices of the Royal Astronomical Society
Volume499
Issue number2
DOIs
Publication statusPublished - Dec 2020

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