scholarly journals Reproducing sub-millimetre galaxy number counts with cosmological hydrodynamic simulations

2021 ◽  
Author(s):  
Christopher C Lovell ◽  
James E Geach ◽  
Romeel Davé ◽  
Desika Narayanan ◽  
Qi Li
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Formation Rate ◽  
Small Contribution ◽  
Redshift Distribution ◽  
Hydrodynamic Simulation ◽  
Hydrodynamic Simulations ◽  
Multiple Components ◽  
Number Counts ◽  
Good Agreement

Abstract Matching the number counts of high-z sub-millimetre-selected galaxies (SMGs) has been a long standing problem for galaxy formation models. In this paper, we use 3D dust radiative transfer to model the sub-mm emission from galaxies in the Simba cosmological hydrodynamic simulations, and compare predictions to the latest single-dish observational constraints on the abundance of 850 μm-selected sources. We find good agreement with the shape of the integrated 850 μm luminosity function, and the normalisation is within 0.25 dex at >3 mJy, unprecedented for a fully cosmological hydrodynamic simulation, along with good agreement in the redshift distribution of bright SMGs. The agreement is driven primarily by Simba’s good match to infrared measures of the star formation rate (SFR) function between z = 2 − 4 at high SFRs. Also important is the self-consistent on-the-fly dust model in Simba, which predicts, on average, higher dust masses (by up to a factor of 2.5) compared to using a fixed dust-to-metals ratio of 0.3. We construct a lightcone to investigate the effect of far-field blending, and find that 52% of sources are blends of multiple components, which makes a small contribution to the normalisation of the bright-end of the number counts. We provide new fits to the 850 μm luminosity as a function of SFR and dust mass. Our results demonstrate that solutions to the discrepancy between sub-mm counts in simulations and observations, such as a top-heavy IMF, are unnecessary, and that sub-millimetre-bright phases are a natural consequence of massive galaxy evolution.

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 First Light And Reionization Epoch Simulations (FLARES) – I. Environmental dependence of high-redshift galaxy evolution

2020 ◽  
Vol 500 (2) ◽  
pp. 2127-2145
Author(s):  
Christopher C Lovell ◽  
Aswin P Vijayan ◽  
Peter A Thomas ◽  
Stephen M Wilkins ◽  
David J Barnes ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Dynamic Range ◽  
High Redshift ◽  
Formation Rate ◽  
Mass Function ◽  
Distribution Functions ◽  
Large Area ◽  
Composite Distribution ◽  
Environmental Dependence

ABSTRACT We introduce the First Light And Reionisation Epoch Simulations (FLARES), a suite of zoom simulations using the EAGLE model. We resimulate a range of overdensities during the Epoch of Reionization (EoR) in order to build composite distribution functions, as well as explore the environmental dependence of galaxy formation and evolution during this critical period of galaxy assembly. The regions are selected from a large $(3.2 \, \mathrm{cGpc})^{3}$ parent volume, based on their overdensity within a sphere of radius 14 h−1 cMpc. We then resimulate with full hydrodynamics, and employ a novel weighting scheme that allows the construction of composite distribution functions that are representative of the full parent volume. This significantly extends the dynamic range compared to smaller volume periodic simulations. We present an analysis of the galaxy stellar mass function (GSMF), the star formation rate distribution function (SFRF), and the star-forming sequence (SFS) predicted by FLARES, and compare to a number of observational and model constraints. We also analyse the environmental dependence over an unprecedented range of overdensity. Both the GSMF and the SFRF exhibit a clear double-Schechter form, up to the highest redshifts (z = 10). We also find no environmental dependence of the SFS normalization. The increased dynamic range probed by FLARES will allow us to make predictions for a number of large area surveys that will probe the EoR in coming years, carried out on new observatories such as Roman and Euclid.

scholarly journals Towards a census of high-redshift dusty galaxies with Herschel

2018 ◽  
Vol 614 ◽  
pp. A33 ◽  
Author(s):  
D. Donevski ◽  
V. Buat ◽  
F. Boone ◽  
C. Pappalardo ◽  
M. Bethermin ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Virgo Cluster ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Redshift Distribution ◽  
Star Forming

Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z = 2 − 3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z ≥ 4 galaxies they often consider the sources with fluxes rising from 250 μm to 500 μm (so-called “500 μm-risers”). Herschel surveys offer a unique opportunity to efficiently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500 μm-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution fitting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500 μm-risers over 55 deg2, imposing the criteria: S500 > S350 > S250, S250 > 13.2 mJy and S500 > 30 mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24+6-5% based on models. Conclusions. We present the faintest sample of 500 μm-risers down to S250 = 13.2 mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the flux-corrected star formation rate density at 4 < z < 5 with the 500 μm-risers and find it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z > 4 sources.

scholarly journals Reconstructing Orbits of Galaxies in Extreme Regions (ROGER) II: reliability of projected phase-space in our understanding of galaxy populations

2021 ◽  
Author(s):  
Valeria Coenda ◽  
Martín de los Rios ◽  
Hernán Muriel ◽  
Sofía A Cora ◽  
Héctor J Martínez ◽  
...  
Keyword(s):  
Phase Space ◽  
Galaxy Formation ◽  
Formation Rate ◽  
Stellar Mass ◽  
Cluster Galaxies ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Galaxy Population ◽  
2D Data ◽  
Good Agreement

Abstract We connect galaxy properties with their orbital classification by analysing a sample of galaxies with stellar mass M⋆ ≥ 108.5h−1M⊙ residing in and around massive and isolated galaxy clusters with mass M200 &gt; 1015h−1M⊙ at redshift z = 0. The galaxy population is generated by applying the semi-analytic model of galaxy formation sag on the cosmological simulation MultiDark Planck 2. We classify galaxies considering their real orbits (3D) and their projected phase-space position using the roger  code (2D). We define five categories: cluster galaxies, galaxies that have recently fallen into a cluster, backsplash galaxies, infalling galaxies, and interloper galaxies. For each class, we analyse the 0.1(g − r) colour, the specific star formation rate (sSFR), and the stellar age, as a function of the stellar mass. For the 3D classes, we find that cluster galaxies have the lowest sSFR, and are the reddest and the oldest, as expected from environmental effects. Backsplash galaxies have properties intermediate between the cluster and recent infaller galaxies. For each 2D class, we find an important contamination by other classes. We find it necessary to separate the galaxy populations in red and blue to perform a more realistic analysis of the 2D data. For the red population, the 2D results are in good agreement with the 3D predictions. Nevertheless, when the blue population is considered, the 2D analysis only provides reliable results for recent infallers, infalling galaxies and interloper galaxies.

scholarly journals The Evolution of Galaxies in the Last 10 GYR

1994 ◽  
Vol 161 ◽  
pp. 649-651
Author(s):  
K. Rakos ◽  
J. Schombert ◽  
T. Maindl ◽  
N. Unger ◽  
P. Obitsch
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Rest Frame ◽  
Blue Colour ◽  
Star Forming ◽  
Blue Galaxies ◽  
Single Burst ◽  
The Mean ◽  
The Difference ◽  
Good Agreement

Rest-frame Strömgren colours are presented for a large number of galaxies in rich clusters between z = 0 and z = 1. Our observations confirm a strong, rest-frame, Butcher-Oemler effect where the fraction of blue galaxies increases from 20% at z &lt; 0.4 to 80% at z = 0.9. After isolating the red objects in each cluster we have compared the mean colour of these old, non-star forming objects with SED models from the literature as a test for passive galaxy evolution in ellipticals. We find good agreement with single burst models which predict an epoch of galaxy formation from z = 2 to 5 (Rakos et al. 1988, 1991; Rakos &amp; Schombert 1993). Although the results demonstrate a great deal of hope for modelling the fine details of colour evolution when our samples are extended into the near- and far-IR, there are reasons to believe that galaxies become, observationally, much more complicated beyond redshifts of 1. The rate of blue colour evolution between 0.6 and 0.9 suggests that by a redshift of 1.5 it will be impossible to tell the difference between galaxies which have completed a single burst at a formation redshift of 2 or ones which are undergoing constant star formation.

scholarly journals Evidence for Galaxy Formation at High Redshift

2001 ◽  
Vol 204 ◽  
pp. 347-357
Author(s):  
Tom Shanks ◽  
Nigel Metcalfe ◽  
Dick Fong ◽  
Henry McCracken ◽  
Ana Campos ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Dwarf Galaxy ◽  
High Redshift ◽  
Formation Rate ◽  
Space Density ◽  
High Redshift Galaxies ◽  
Local Space ◽  
Deep Fields ◽  
Using Data ◽  
Number Counts

Metcalfe et al. (1995, 1996) have shown that galaxy counts from the UV to the near-IR are well-fitted by simple evolutionary models where the space density of galaxies remains constant with look-back time while the star-formation rate rises exponentially. We now extend these results, first by using data from the Herschel Deep Field to show that these same models give detailed fits to the faint galaxy r - i : b - r colour-colour diagram. We then use these models to predict the number counts of high redshift galaxies detected by the Lyman break technique. At z ≈ 3 there is almost exact agreement between our prediction and the data, suggesting that the space density of galaxies at z ≈ 3 may be close to its local value. At z ≈ 4 the space density of bright galaxies remains unchanged; however, the space density of dwarf galaxies is significantly lower than it is locally, suggesting that we have detected an epoch of dwarf galaxy formation at z ≈ 4. Finally, significant numbers of Lyman-break galaxy candidates are also detected at z ≈ 6 in the Hubble and Herschel Deep Fields; taking this observation together with a number of recent detections of spectroscopically confirmed z ≈ 6 galaxies suggests that the space density of bright galaxies at z ≈ 6 remains comparable to the local space density, and thus that the epoch of formation of bright galaxies may lie at yet higher redshift.

scholarly journals The evolution of sizes and specific angular momenta in hierarchical models of galaxy formation and evolution

2019 ◽  
Vol 487 (4) ◽  
pp. 5649-5665 ◽  
Author(s):  
Anna Zoldan ◽  
Gabriella De Lucia ◽  
Lizhi Xie ◽  
Fabio Fontanot ◽  
Michaela Hirschmann
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
High Redshift ◽  
Retention Factor ◽  
Mass Relation ◽  
Massive Galaxies ◽  
Star Forming ◽  
Stellar Halo ◽  
Compact Galaxies ◽  
Good Agreement

ABSTRACTWe extend our previous work focused at z ∼ 0, studying the redshift evolution of galaxy dynamical properties using the state-of-the-art semi-analytic model GAEA (GAlaxy Evolution and Assembly): we show that the predicted size–mass relation for discy/star-forming and quiescent galaxies is in good agreement with observational estimates, up to z ∼ 2. Bulge-dominated galaxies have sizes that are offset low with respect to observational estimates, mainly due to our implementation of disc instability at high redshift. At large masses, both quiescent and bulge-dominated galaxies have sizes smaller than observed. We interpret this as a consequence of our most massive galaxies having larger gas masses than observed, and therefore being more affected by dissipation. We argue that a proper treatment of quasar-driven winds is needed to alleviate this problem. Our model compact galaxies have number densities in agreement with observational estimates and they form most of their stars in small and low angular momentum high-z haloes. GAEA predicts that a significant fraction of compact galaxies forming at high-z is bound to merge with larger structures at lower redshifts: therefore they are not the progenitors of normal-size passive galaxies at z = 0. Our model also predicts a stellar–halo size relation that is in good agreement with observational estimates. The ratio between stellar size and halo size is proportional to the halo spin and does not depend on stellar mass but for the most massive galaxies, where active galactic nucleus feedback leads to a significant decrease of the retention factor (from about 80 per cent to 20 per cent).

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 Galaxy formation in the brane world I: overview and first results

2021 ◽  
Author(s):  
César Hernández-Aguayo ◽  
Christian Arnold ◽  
Baojiu Li ◽  
Carlton M Baugh
Keyword(s):  
Dark Matter ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Modified Gravity ◽  
Formation Rate ◽  
Brane World ◽  
Stellar Content ◽  
Braneworld Model ◽  
Hydrodynamical Simulations ◽  
The Impact

Abstract We carry out “full-physics” hydrodynamical simulations of galaxy formation in the normal-branch Dvali-Gabadadze-Porrati (nDGP) braneworld model using a new modified version of the Arepo code and the IllustrisTNG galaxy formation model. We simulate two nDGP models (N5 and N1) which represent, respectively, weak and moderate departures from GR, in boxes of sizes 62 h−1Mpc and 25 h−1Mpc using 2 × 5123 dark matter particles and initial gas cells. This allows us to explore, for the first time, the impact of baryonic physics on galactic scales in braneworld models of modified gravity and to make predictions on the stellar content of dark matter haloes and galaxy evolution through cosmic time in these models. We find significant differences between the GR and nDGP models in the power spectra and correlation functions of gas, stars and dark matter of up to ∼25 per cent on large scales. Similar to their impact in the standard cosmological model (ΛCDM), baryonic effects can have a significant influence over the clustering of the overall matter distribution, with a sign that depends on scale. Studying the degeneracy between modified gravity and galactic feedback in these models, we find that these two physical effects on matter clustering can be cleanly disentangled, allowing for a method to accurately predict the matter power spectrum with baryonic effects included, without having to run hydrodynamical simulations. Depending on the braneworld model, we find differences compared with GR of up to ∼15 per cent in galaxy properties such as the stellar-to-halo-mass ratio, galaxy stellar mass function, gas fraction and star formation rate density. The amplitude of the fifth force is reduced by the presence of baryons in the very inner part of haloes, but this reduction quickly becomes negligible above ∼0.1 times the halo radius.

scholarly journals ISOCAM Deep Surveys and the Cosmic Infrared Background

2002 ◽  
Vol 12 ◽  
pp. 485-488
Author(s):  
David Elbaz
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Steep Slope ◽  
Infrared Galaxies ◽  
Redshift Distribution ◽  
Infrared Background ◽  
Number Counts ◽  
Hubble Deep Field

AbstractThe steep slope of the ISOCAM 15 μmnumber counts indicates that infrared galaxies have strongly evolved sincez∼ 1 − 1.5. A nearly complete spectroscopic sample of ISOCAM galaxies in the Hubble Deep Field North (HDFN) shows that their redshift distribution is peaked aroundz∼ 0.8. We show that the 7 μmluminosity of local galaxies is correlated with their 8-1000 μmluminosity, and therefore star formation rate (SFR). We use this correlation in the rest-frame of the ISOCAM galaxies to deduce their IR luminosities (∼ 4 × 1011L⊙), SFR (∼ 80M⊙yr−1) and contribution to the peak of the cosmic IR background (CIRB) at 140 μm. We find that they most probably produce the bulk of the CIRB.

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