scholarly journals Prospects for distinguishing galaxy evolution models with surveys at redshifts z ≳ 4

2020 ◽  
Vol 499 (3) ◽  
pp. 4534-4544 ◽  
Author(s):  
Jordan Mirocha
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Duty Cycle ◽  
Cosmic Time ◽  
Galaxy Surveys ◽  
Stellar Feedback ◽  
Luminosity Functions ◽  
Galaxy Bias ◽  
The Masses

ABSTRACT Many semi-empirical galaxy formation models have recently emerged to interpret high-z galaxy luminosity functions and make predictions for future galaxy surveys. A common approach assumes a ‘universal’ star formation efficiency, f*, independent of cosmic time but strongly dependent on the masses of dark matter haloes. Though this class of models has been very successful in matching observations over much of cosmic history, simple stellar feedback models do predict redshift evolution in f* and are commonly used in semi-analytic models. In this work, we calibrate a set of universal f* and feedback-regulated models to the same set of rest-ultraviolet z ≳ 4 observations and find that a rapid, ∼(1 + z)−3/2 decline in both the efficiency of dust production and duty cycle of star formation are needed to reconcile feedback-regulated models with current observations. By construction, these models remain nearly identical to universal f* models in rest-ultraviolet luminosity functions (UVLFs) and colours. As a result, the only way to distinguish these competing scenarios is either via (i) improved constraints on the clustering of galaxies – universal and feedback-regulated models differ in predictions for the galaxy bias by 0.1 ≲ Δ〈b〉 ≲ 0.3 over 4 ≲ z ≲ 10 – or (ii) independent constraints on the dust contents and/or duty cycle of star formation. This suggests that improved constraints on the ‘dustiness’ and ‘burstiness’ of high-z galaxies will not merely add clarity to a given model of star formation in high-z galaxies, but rather fundamentally determine our ability to identify the correct model in the first place.

scholarly journals The elephant in the bathtub: when the physics of star formation regulate the baryon cycle of galaxies

2020 ◽  
Vol 500 (2) ◽  
pp. 2000-2011
Author(s):  
Jindra Gensior ◽  
J M Diederik Kruijssen
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
High Redshift ◽  
Formation Rate ◽  
Cosmic Time ◽  
Free Fall ◽  
Isolated Galaxies ◽  
The Galaxy ◽  
Galaxy Masses

ABSTRACT In simple models of galaxy formation and evolution, star formation is solely regulated by the amount of gas present in the galaxy. However, it has recently been shown that star formation can be suppressed by galactic dynamics in galaxies that contain a dominant spheroidal component and a low gas fraction. This ‘dynamical suppression’ is hypothesized to also contribute to quenching gas-rich galaxies at high redshift, but its impact on the galaxy population at large remains unclear. In this paper, we assess the importance of dynamical suppression in the context of gas regulator models of galaxy evolution through hydrodynamic simulations of isolated galaxies, with gas-to-stellar mass ratios of 0.01–0.20 and a range of galactic gravitational potentials from disc-dominated to spheroidal. Star formation is modelled using a dynamics-dependent efficiency per free-fall time, which depends on the virial parameter of the gas. We find that dynamical suppression becomes more effective at lower gas fractions and quantify its impact on the star formation rate as a function of gas fraction and stellar spheroid mass surface density. We combine the results of our simulations with observed scaling relations that describe the change of galaxy properties across cosmic time, and determine the galaxy mass and redshift range where dynamical suppression may affect the baryon cycle. We predict that the physics of star formation can limit and regulate the baryon cycle at low redshifts (z ≲ 1.4) and high galaxy masses (M* ≳ 3 × 1010 M⊙), where dynamical suppression can drive galaxies off the star formation main sequence.

scholarly journals Quasi-equilibrium models of high-redshift disc galaxy evolution

2020 ◽  
Vol 500 (3) ◽  
pp. 3394-3412
Author(s):  
Steven R Furlanetto
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
High Redshift ◽  
Formation Rate ◽  
New Physics ◽  
Small Scale ◽  
Quasi Equilibrium ◽  
Mass Relation ◽  
Disc Galaxy

ABSTRACT In recent years, simple models of galaxy formation have been shown to provide reasonably good matches to available data on high-redshift luminosity functions. However, these prescriptions are primarily phenomenological, with only crude connections to the physics of galaxy evolution. Here, we introduce a set of galaxy models that are based on a simple physical framework but incorporate more sophisticated models of feedback, star formation, and other processes. We apply these models to the high-redshift regime, showing that most of the generic predictions of the simplest models remain valid. In particular, the stellar mass–halo mass relation depends almost entirely on the physics of feedback (and is thus independent of the details of small-scale star formation) and the specific star formation rate is a simple multiple of the cosmological accretion rate. We also show that, in contrast, the galaxy’s gas mass is sensitive to the physics of star formation, although the inclusion of feedback-driven star formation laws significantly changes the naive expectations. While these models are far from detailed enough to describe every aspect of galaxy formation, they inform our understanding of galaxy formation by illustrating several generic aspects of that process, and they provide a physically grounded basis for extrapolating predictions to faint galaxies and high redshifts currently out of reach of observations. If observations show violations from these simple trends, they would indicate new physics occurring inside the earliest generations of galaxies.

scholarly journals In pursuit of giants

2020 ◽  
Vol 644 ◽  
pp. A144
Author(s):  
D. Donevski ◽  
A. Lapi ◽  
K. Małek ◽  
D. Liu ◽  
C. Gómez-Guijarro ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Main Sequence ◽  
Stellar Mass ◽  
Starburst Galaxies ◽  
Analytical Models ◽  
Physical Parameters ◽  
Star Forming ◽  
Galaxy Populations

The dust-to-stellar mass ratio (Mdust/M⋆) is a crucial, albeit poorly constrained, parameter for improving our understanding of the complex physical processes involved in the production of dust, metals, and stars in galaxy evolution. In this work, we explore trends of Mdust/M⋆ with different physical parameters and using observations of 300 massive dusty star-forming galaxies detected with ALMA up to z ≈ 5. Additionally, we interpret our findings with different models of dusty galaxy formation. We find that Mdust/M⋆ evolves with redshift, stellar mass, specific star formation rates, and integrated dust size, but that evolution is different for main-sequence galaxies than it is for starburst galaxies. In both galaxy populations, Mdust/M⋆ increases until z ∼ 2, followed by a roughly flat trend towards higher redshifts, suggesting efficient dust growth in the distant universe. We confirm that the inverse relation between Mdust/M⋆ and M⋆ holds up to z ≈ 5 and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that the Mdust/M⋆ in starbursts reflects the increase in molecular gas fraction with redshift and attains the highest values for sources with the most compact dusty star formation. State-of-the-art cosmological simulations that include self-consistent dust growth have the capacity to broadly reproduce the evolution of Mdust/M⋆ in main-sequence galaxies, but underestimating it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust-growth timescales relative to observations. The results of phenomenological models based on the main-sequence and starburst dichotomy as well as analytical models that include recipes for rapid metal enrichment are consistent with our observations. Therefore, our results strongly suggest that high Mdust/M⋆ is due to rapid dust grain growth in the metal-enriched interstellar medium. This work highlights the multi-fold benefits of using Mdust/M⋆ as a diagnostic tool for: (1) disentangling main-sequence and starburst galaxies up to z ∼ 5; (2) probing the evolutionary phase of massive objects; and (3) refining the treatment of the dust life cycle in simulations.

scholarly journals The impact of stellar feedback on high-z galaxy populations

2015 ◽  
Vol 11 (S319) ◽  
pp. 26-26
Author(s):  
Michaela Hirschmann ◽  
Gabriella De Lucia
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Large Scale ◽  
Mass Function ◽  
Chemical Enrichment ◽  
Stellar Feedback ◽  
Feedback Scheme ◽  
Galaxy Populations ◽  
Improved Model ◽  
The Impact

AbstractOne major deficiency of state-of-the-art galaxy formation models consists in their inability of capturing the observed galaxy downsizing trend significantly over-estimating the number density of low-mass galaxies, in particular at high redshifts. Employing an enhanced galaxy formation model with a full chemical enrichment scheme (DeLucia et al., 2014), we present an improved model for stellar feedback (based on parametrizations from cosmological zoom simulations), in which strong gas outflows occur due to bursty star formation at high z, while star formation is mainly “quiescent” not causing any significant outflows anymore at low z. Due to the stronger gas outflows at high z, early star formation is strongly delayed towards later times. This helps to sufficiently detach the evolution of galaxy growth from the hiearchical dark matter assembly resulting in a fairly good agreement with the evolution of the observed stellar mass function (SMF, see Fig. 1). With our new feedback scheme, we can also successfully reproduce many other observational constraints, such as the metallicity content, the cold gas fractions or the quiescent galaxy fractions at both low and high redshifts. The resulting new-generation galaxy catalogues (Hirschmann et al., in prep) based on that model are expected to significantly contribute to the interpretation of current and up-coming large-scale surveys (HST, JWST, Euclid). This will, in turn, provide a rapid verification and refinement of our modeling.

scholarly journals The Connection Between Galaxies and Their Dark Matter Halos

2018 ◽  
Vol 56 (1) ◽  
pp. 435-487 ◽  
Author(s):  
Risa H. Wechsler ◽  
Jeremy L. Tinker
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
Strong Function ◽  
Galaxy Surveys ◽  
Narrow Region ◽  
Open Questions ◽  
Galaxy Halo

In our modern understanding of galaxy formation, every galaxy forms within a dark matter halo. The formation and growth of galaxies over time is connected to the growth of the halos in which they form. The advent of large galaxy surveys as well as high-resolution cosmological simulations has provided a new window into the statistical relationship between galaxies and halos and its evolution. Here, we define this galaxy–halo connection as the multivariate distribution of galaxy and halo properties that can be derived from observations and simulations. This galaxy–halo connection provides a key test of physical galaxy-formation models; it also plays an essential role in constraints of cosmological models using galaxy surveys and in elucidating the properties of dark matter using galaxies. We review techniques for inferring the galaxy–halo connection and the insights that have arisen from these approaches. Some things we have learned are that galaxy-formation efficiency is a strong function of halo mass; at its peak in halos around a pivot halo mass of 1012M⊙, less than 20% of the available baryons have turned into stars by the present day; the intrinsic scatter in galaxy stellar mass is small, less than 0.2 dex at a given halo mass above this pivot mass; below this pivot mass galaxy stellar mass is a strong function of halo mass; the majority of stars over cosmic time were formed in a narrow region around this pivot mass. We also highlight key open questions about how galaxies and halos are connected, including understanding the correlations with secondary properties and the connection of these properties to galaxy clustering.

GALAXY EVOLUTION THROUGH THE COSMIC TIME

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1371-1377
Author(s):  
T. P. IDIART ◽  
J. A. F. PACHECO ◽  
J. SILK
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Cosmic Time ◽  
Evolutionary Model ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Star Formation Activity ◽  
Formation And Evolution ◽  
The Universe

Elliptical galaxies are the best systems to study the early star formation activity in the universe. This work aims to understand the formation and evolution of these objects through the study of the integrated properties of their stellar populations. Here an evolutionary model is developed and their predicted spectrophotometric properties are presented.

scholarly journals Early-type galaxy formation: understanding the role of the environment

2014 ◽  
Vol 10 (S309) ◽  
pp. 291-292
Author(s):  
Ricardo Demarco ◽  
Alessandro Rettura ◽  
Chris Lidman ◽  
Julie Nantais ◽  
Yara Jaffe ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Early Type ◽  
Cluster Galaxy ◽  
Cluster Galaxies ◽  
Physical Mechanisms ◽  
Characteristic Features ◽  
Early Type Galaxy

AbstractOne of the most characteristic features of galaxy clusters is the so-called “red sequence” (RS) of early-type galaxies. Since these galaxies are, in general, devoid of gas and dust, their red colors are mainly a consequence of their passive nature. However, the physical mechanisms responsible for quenching their star formation, thus originating the RS, are poorly understood. Environmental effects should play a significant role in the formation of the RS by transforming the observed galaxy properties from late to early-type ones. In this respect, we have initiated a KMOS program aimed at studying the kinematical structure of cluster galaxies at 0.8 < z < 1.7 in an effort to disentangle the physical mechanisms responsible for cluster galaxy evolution and the formation of the RS.

scholarly journals Modeling Formation of Globular Clusters: Beacons of Galactic Star Formation

2010 ◽  
Vol 6 (S270) ◽  
pp. 381-384
Author(s):  
Oleg Y. Gnedin
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Cluster Formation ◽  
Star Clusters ◽  
Mass Function ◽  
Giant Molecular Clouds ◽  
Early Galaxies ◽  
The Masses

AbstractModern hydrodynamic simulations of galaxy formation are able to predict accurately the rates and locations of the assembly of giant molecular clouds in early galaxies. These clouds could host star clusters with the masses and sizes of real globular clusters. I describe current state-of-the-art simulations aimed at understanding the origin of the cluster mass function and metallicity distribution. Metallicity bimodality of globular cluster systems appears to be a natural outcome of hierarchical formation and gradually declining fraction of cold gas in galaxies. Globular cluster formation was most prominent at redshifts z > 3, when massive star clusters may have contributed as much as 20% of all galactic star formation.

scholarly journals Gas accretion regulates the scatter of the mass–metallicity relation

2020 ◽  
Vol 498 (3) ◽  
pp. 3215-3227
Author(s):  
Gabriella De Lucia ◽  
Lizhi Xie ◽  
Fabio Fontanot ◽  
Michaela Hirschmann
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Formation Rate ◽  
Gas Content ◽  
Stellar Feedback ◽  
Accretion Rates ◽  
The Galaxy ◽  
Gas Cooling ◽  
Gas Accretion ◽  
Cold Gas

ABSTRACT In this paper, we take advantage of the GAlaxy Evolution and Assembly (GAEA) semi-analytic model to analyse the origin of secondary dependencies in the local galaxy mass–gas metallicity relation. Our model reproduces quite well the trends observed in the local Universe as a function of galaxy star formation rate and different gas-mass phases. We show that the cold gas content (whose largest fraction is represented by the atomic gas phase) can be considered as the third parameter governing the scatter of the predicted mass–metallicity relation, in agreement with the most recent observational measurements. The trends can be explained with fluctuations of the gas accretion rates: a decrease of the gas supply leads to an increase of the gas metallicity due to star formation, while an increase of the available cold gas leads to a metallicity depletion. We demonstrate that the former process is responsible for offsets above the mass–metallicity relation, while the latter is responsible for deviations below the mass–metallicity relation. In low- and intermediate-mass galaxies, these negative offsets are primarily determined by late gas cooling dominated by material that has been previously ejected due to stellar feedback.

scholarly journals A two-state model for galaxy bias

2020 ◽  
Vol 493 (3) ◽  
pp. 3449-3463
Author(s):  
Andrew Repp ◽  
István Szapudi
Keyword(s):  
Galaxy Formation ◽  
State Model ◽  
Galaxy Surveys ◽  
Bias Model ◽  
Reliable Model ◽  
The Galaxy ◽  
Dirac Distribution ◽  
Galaxy Bias ◽  
Conventional Models ◽  
Two State Model

ABSTRACT A reliable model of galaxy bias is necessary for interpreting data from future dense galaxy surveys. Conventional linear and quadratic bias models are unphysical, often predicting negative galaxy densities (δg &lt; −1) in voids, which potentially contain half of a survey’s available cosmological information. Here we present a physically motivated alternative by assuming two energetically distinct subhalo states. Our approximations – namely, local galaxy formation, rough equivalence of galaxy-hosting subhaloes, and universal energetic favourability for the galaxy-hosting state – result in a bias model with only two free parameters; mathematically, the model (in the correct variables) yields a Fermi–Dirac distribution or (equivalently) an interactionless Ising model with an external field. The model yields sensible (and physical) predictions for both high- and low-density regions. We test the model using a catalogue of Millennium Simulation galaxies in cubical survey pixels with side lengths from 2 h−1–31 h−1 Mpc, at redshifts from 0 to 2. We find the two-state model markedly superior to linear and quadratic bias models on scales smaller than 10 h−1 Mpc, while those conventional models fare better on scales larger than 30 h−1 Mpc. Though the largest scale of applicability is likely to depend on the galaxy catalogue employed, the two-state model should be superior on any scale with a non-negligible fraction of cells devoid of galaxies.

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