The n ature of submillimetre galaxies in cosmological hydrodynamic simulations

By R. Dav'e, K. Finlator, B. Oppenheimer, Mark A. Fardal, Neal Katz, D. Kerevs, D. Weinberg. 2009

187 citations recorded by the source corpus.

We study the nature of rapidly star-forming galaxies at z= 2 in cosmological hydrodynamic simulations, and compare their properties to observations of submillimetre galaxies (SMGs). We identify simulated SMGs as the most rapidly star-forming systems that match the observed number density of SMGs. In our models, SMGs are massive galaxies sitting at the centres of large potential wells, being fed by smooth infall and gas-rich satellites at rates comparable to their star formation rates (SFRs). They are not typically undergoing major mergers that significantly boost their quiescent SFR, but they still often show complex gas morphologies and kinematics. Our simulated SMGs have stellar masses of M*∼ 1011−11.7 M⊙, SFRs of ∼180–500 M⊙ yr−1, a clustering length of ∼10 h−1 Mpc and solar metallicities. The SFRs are lower than those inferred from far-infrared (far-IR) data by ∼×3, which we suggest may owe to one or more systematic effects in the SFR calibrations. SMGs at z= 2 live in ∼1013 M⊙ haloes, and by z= 0 they mostly end up as brightest group galaxies in ∼1014 M⊙ haloes. We predict that higher M* SMGs should have on average lower specific SFRs, less disturbed morphologies and higher clustering. We also predict that deeper far-IR surveys will smoothly join SMGs on to the massive end of the SFR–M* relationship defined by lower mass z∼ 2 galaxies. Overall, our simulated rapid star-formers provide as good a match to available SMG data as merger-based scenarios, offering an alternative scenario that emerges naturally from cosmological simulations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6b7b5ae26eebf2c03c0e154d8c1801bd646e5ae8

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Citations in the corpus

The evolution of the dust temperatures of galaxies in the SFR–M∗ plane up to z ~ 2 (2013, background): “…with a secular mode of star formation, likely sustained by a continuous gas accretion from the IGM and along the cosmic web (Dekel et al. 2009; Davé et al. 2010), while star-forming galaxies located far above the MS evolve through strong starbursts with short duty-cycles, mainly triggered by…”
CONSTRAINTS ON THE ASSEMBLY AND DYNAMICS OF GALAXIES. I. DETAILED REST-FRAME OPTICAL MORPHOLOGIES ON KILOPARSEC SCALE OF z ∼ 2 STAR-FORMING GALAXIES (2010, background): “…(2008) falls well above this luminosity threshold, yet the processes giving rise to extreme bolometric luminosities at high redshift may be more diverse, based on theoretical grounds (e.g., Davé et al. 2010), and supported by observational evidence (e.g., Dasyra et al. 2008; Swinbank et al. 2010).”
HYDRODYNAMICS OF HIGH-REDSHIFT GALAXY COLLISIONS: FROM GAS-RICH DISKS TO DISPERSION-DOMINATED MERGERS AND COMPACT SPHEROIDS (2010, background): “Another model of SMGs suggests that they are the high-mass end of cold-flow galaxies, with no mergers involved (Davé et al. 2010).”
The properties of the interstellar medium within a star-forming galaxy at z= 2.3 (2010, background): “Analogy to local ultra-luminous infrared galaxies (ULIRGs) would argue for compact starbursts triggered by mergers, although secular bursts in massive gas disks are also feasible (e.g. Davé et al. 2010).”
A fundamental relation between the metallicity, gas content, and stellar mass of local galaxies (2013, background): “…for the relation have focused on explanations involving the global behaviour of gas (i.e. Audouze & Tinsley 1976), which can serve both as a pristine infalling diluent (e.g. Finlator & Davé 2008; Davé et al. 2010) and as a metal-rich outflow (Spitoni et al. 2010; Peeples & Shankar 2011).”
Cool Gas in High-Redshift Galaxies (2013, background): “Dave et al. (2010) suggest that the CMA phenomenon may even scale up to HyLIRGs, and that a substantial fraction of high–z SMGs could be fed primarily by CMA, and not major mergers.”
A physical model for z∼ 2 dust-obscured galaxies (2009, background): “…to form in massive starbursts which both observational and theoretical evidence imply may be merger-driven (e.g. Chapman et al. 2003; Tacconi et al. 2006, 2008; Baugh et al. 2005; Swinbank et al. 2008; Narayanan et al. 2009, 2010, though see Davé et al. (2010) for an alternative interpretation).”
KILOPARSEC-SCALE DUST DISKS IN HIGH-REDSHIFT LUMINOUS SUBMILLIMETER GALAXIES (2016, methodology): “Finally, some models propose that SMGs may simply represent the most massive extension of the normal z > 2 star–forming galaxy population (e.g., Kereš et al. 2005, 2009b,a; Davé et al. 2010).”
Evolution of the atomic and molecular gas content of galaxies (2013, result): “However, numerical hydrodynamic simulations suffer from the same problems (Weinmann et al. 2012; Davé et al. 2010), and in fact produce very similar predictions to the SAMs, leading most theorists to conclude that it is likely to be limitations in our understanding of the sub-grid processes of…”
A general model for the CO–H2 conversion factor in galaxies with applications to the star formation law (2011, background): “2 of Davé et al. 2010, though see Keres et al. 2011; Vogelsberger et al. 2011 and Sijacki et al. 2011).”
A Herschel view of the far-infrared properties of submillimetre galaxies (2012, background): “Indeed, while simulations of major mergers are able to reproduce such extreme SFRs, simulations in a cosmological context have had great difficulties accounting for the estimated SFRs and number counts (Baugh et al. 2005; Davé et al. 2010).”
Towards a more realistic population of bright spiral galaxies in cosmological simulations (2013, result): “Narayanan et al. (2012) recently reported a similar discrepancy for the simulations of Davé et al. (2010).”
Submillimetre galaxies in a hierarchical universe: number counts, redshift distribution, and implications for the IMF (2012, methodology): “2 of Davé et al. (2010) shows that all their simulated galaxies lie significantly under the observed SFR–”
PACS Evolutionary Probe (PEP) – a Herschel key program (2011, background): “This confirmation of huge O(1000M⊙yr−1) star formation rates for SMGs is in support of a predominantly merger nature of SMGs, since such star formation rates are very hard to sustain with secular processes (e.g. Davé et al. 2010).”
The stellar masses and specific star-formation rates of submillimetre galaxies (2011, background): “…they simply represent the most massive extension of the normal star-forming galaxy population in the young active Universe at z > 2 (as predicted by Davé et al. 2010 in cosmological hydrodynamic simulations), or whether they are extreme outliers in terms of specific star-formation rate (sSFR).”
Dusty Star Forming Galaxies at High Redshift (2014, methodology): “Shimizu et al. (2012) find many more galaxies with SFR > 500 M⊙ yr−1 than Davé et al. (2010), though also simulate manymore galaxies such that it is not clear how the percentages compare.”
WHAT DOES A SUBMILLIMETER GALAXY SELECTION ACTUALLY SELECT? THE DEPENDENCE OF SUBMILLIMETER FLUX DENSITY ON STAR FORMATION RATE AND DUST MASS (2010, background): “Furthermore, roughly estimating submm counts using estimates of high-redshift major merger rates and the short duty cycle of merger-induced starbursts suggests that there may not be enough major mergers to account for the SMG population (Davé et al. 2010).”