http://arxiv.org/abs/2007.09853
We thoroughly explore the properties of (sub)-millimeter (mm) selected galaxies (SMGs) in the Shark semi-analytic model of galaxy formation. Compared to observations, the predicted number counts at wavelengths (lambda) 0.6-2mm and redshift distributions at 0.1-2mm, agree well. At the bright end (>1mJy), Shark galaxies are a mix of mergers and disk instabilities. These galaxies display a stacked FUV-to-FIR spectrum that agrees well with observations. We predict that current optical/NIR surveys are deep enough to detect bright (>1mJy) lambda=0.85-2mm-selected galaxies at z<5, but too shallow to detect counterparts at higher redshift. A JWST 10,000s survey should detect all counterparts for galaxies with $S_{\rm 0.85mm}>0.01$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 >1mJy lambda=0.85-2mm-selected galaxies finding their: (i) stellar masses are $>10^{10.2}M_{\odot}$, with the 2mm ones tracing the most massive galaxies in Shark ($>10^{11}M_{\odot}$); (ii) average specific star formation rates (SFR) are mildly (~3-10x) above the main sequence (MS); (iii) host halo masses are $>10^{12.3}M_{\odot}$, with the 2mm galaxies tracing the most massive halos (proto-clusters); (iv) SMGs have lower dust masses ($\sim 10^{8}M_{\odot}$), higher dust temperatures (~40-45K) and higher rest-frame V-band attenuation (>1.5) than MS galaxies; (v) sizes decrease with redshift, from 4kpc at z=1 to 1kpc at z=4; (vi) the Carbon Monoxide spectral line energy distributions of $S_{\rm 0.85mm}>1$mJy sources peak at 4->3. Finally, we study the contribution of SMGs to the molecular gas and cosmic SFR density (CSFRD) at 0<z<10, finding that >1mJy sources make a negligible contribution at z>3 and z>5, respectively, suggesting current observations have unveiled the majority of the star formation at 0<z<10.
C. Lagos, E. Cunha, A. Robotham, et. al.
Tue, 21 Jul 20
-402/75
Comments: Submitted for publications to MNRAS. 27 pages, 22 of main text and figures. Comments welcome!