Stellar Mass—Halo Mass Relation and Star Formation Efficiency in High-Mass Halos

ABSTRACT We introduce a simple analytic model of galaxy formation that links the growth of dark matter haloes in a cosmological background to the build-up of stellar mass within them. The model aims to identify the physical processes that drive the galaxy-halo co-evolution through cosmic time. The model restricts the role of baryonic astrophysics to setting the relation between galaxies and their haloes. Using this approach, galaxy properties can be directly predicted from the growth of their host dark matter haloes. We explore models in which the effective star formation efficiency within haloes is a function of mass (or virial temperature) and independent of time. Despite its simplicity, the model reproduces self-consistently the shape and evolution of the cosmic star formation rate density, the specific star formation rate of galaxies, and the galaxy stellar mass function, both at the present time and at high redshifts. By systematically varying the effective star formation efficiency in the model, we explore the emergence of the characteristic shape of the galaxy stellar mass function. The origin of the observed double Schechter function at low redshifts is naturally explained by two efficiency regimes in the stellar to halo mass relation, namely, a stellar feedback regulated stage, and a supermassive black hole regulated stage. By providing a set of analytic differential equations, the model can be easily extended and inverted, allowing the roles and impact of astrophysics and cosmology to be explored and understood.

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The stellar-to-halo mass relation over the past 12 Gyr

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936329 ◽

2020 ◽

Vol 634 ◽

pp. A135 ◽

Cited By ~ 6

Author(s):

G. Girelli ◽

L. Pozzetti ◽

M. Bolzonella ◽

C. Giocoli ◽

F. Marulli ◽

...

Keyword(s):

Dark Matter ◽

Star Formation ◽

Galaxy Formation ◽

Stellar Mass ◽

Dark Matter Halo ◽

Mass Relation ◽

Massive Galaxies ◽

Halo Masses ◽

Formation Efficiency ◽

Mass Functions

Aims. Understanding the link between the galaxy properties and the dark matter halos they reside in and their coevolution is a powerful tool for constraining the processes related to galaxy formation. In particular, the stellar-to-halo mass relation (SHMR) and its evolution throughout the history of the Universe provides insights on galaxy formation models and allows us to assign galaxy masses to halos in N-body dark matter simulations. To address these questions, we determine the SHMR throughout the entire cosmic history from z ∼ 4 to the present. Methods. We used a statistical approach to link the observed galaxy stellar mass functions on the COSMOS field to dark matter halo mass functions up to z ∼ 4 from the ΛCDM DUSTGRAIN-pathfinder simulation, which is complete for Mh > 1012.5 M⊙, and extended this to lower masses with a theoretical parameterization. We propose an empirical model to describe the evolution of the SHMR as a function of redshift (either in the presence or absence of a scatter in stellar mass at fixed halo mass), and compare the results with several literature works and semianalytic models of galaxy formation. We also tested the reliability of our results by comparing them to observed galaxy stellar mass functions and to clustering measurements. Results. We derive the SHMR from z = 0 to z = 4, and model its empirical evolution with redshift. We find that M*/Mh is always lower than ∼0.05 and depends both on redshift and halo mass, with a bell shape that peaks at Mh ∼ 1012 M⊙. Assuming a constant cosmic baryon fraction, we calculate the star-formation efficiency of galaxies and find that it is generally low; its peak increases with cosmic time from ∼30% at z ∼ 4 to ∼35% at z ∼ 0. Moreover, the star formation efficiency increases for increasing redshifts at masses higher than the peak of the SHMR, while the trend is reversed for masses lower than the peak. This indicates that massive galaxies (i.e., galaxies hosted at halo masses higher than the SHMR peak) formed with a higher efficiency at higher redshifts (i.e., downsizing effect) and vice versa for low-mass halos. We find a large scatter in results from semianalytic models, with a difference of up to a factor ∼8 compared to our results, and an opposite evolutionary trend at high halo masses. By comparing our results with those in the literature, we find that while at z ∼ 0 all results agree well (within a factor of ∼3), at z > 0 many differences emerge. This suggests that observational and theoretical work still needs to be done. Our results agree well (within ∼10%) with observed stellar mass functions (out to z = 4) and observed clustering of massive galaxies (M* > 1011 M⊙ from z ∼ 0.5 to z ∼ 1.1) in the two-halo regime.

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Possible density dependent local variations in the IMF

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316008012 ◽

2015 ◽

Vol 11 (S315) ◽

Author(s):

Indulekha Kavila ◽

Babitha George

Keyword(s):

Star Formation ◽

Density Dependence ◽

Stellar Mass ◽

High Mass ◽

Gas Density ◽

Stellar Cluster ◽

Scale Free ◽

Formation Efficiency ◽

Massive Clusters ◽

The Imf

AbstractA robust feature of turbulent fragmentation theories is a universal Salpeter like slope (2.2 -2.4), for the mass spectrum of the fragments, at the high mass end. This is so due to the scale-free nature of turbulence and gravity. There are reports of top heavy / flatter Initial Mass Functions (IMF), inferred for many regions where we expect star formation to take place in gas clouds with comparatively higher gas density. Also, a higher Star Formation Efficiency (SFE) for regions of higher gas density has been proposed, to understand the formation of bound stellar systems in which dark matter is not a significant factor affecting the internal dynamics. In turbulent fragmentation models for star formation, we do not expect the mass of the stellar cluster to influence the maximum stellar mass directly and thereby imply a relation between the maximum stellar mass and the cluster mass. However, such a relation may be expected from statistical considerations. In this context, we explore the density dependence of the IMF, that would arise due to denser clouds producing more massive clusters due to the density dependence of the SFE.

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MASS DISTRIBUTION OF DARK MATTER HALO AND SCALE EVOLUTION OF EARLY TYPE GALAXIES

NEWS OF THE NATIONAL ACADEMY OF SCIENCES OF THE REPUBLIC OF KAZAKHSTAN ◽

10.32014/2020.2518-1726.102 ◽

2020 ◽

Vol 6 (334) ◽

pp. 91-98

Author(s):

D. Kairatkyzy ◽

◽

H. C. Quevedo ◽

◽

...

Keyword(s):

Dark Matter ◽

Star Formation ◽

Galaxy Formation ◽

Stellar Mass ◽

Dark Matter Halo ◽

High Mass ◽

Galactic Halos ◽

Mass Relation ◽

Early Type ◽

Survival Fraction

In this paper we use two suites of ultra-high resolution N-body simulations Phoenix and Aquarius Projects to study the assembly history of sub-halos and its dependence on host halo mass. We found that more massive haloes have more progenitors, which is in contrast with former works because they counted dynamical progenitors repeatedly. Less massive halos have larger fraction of dynamical progenitors than more massive ones. The typical accretion time depends strongly on host halo mass. Progenitors of galactic halos are accreted at higher redshift than that of cluster halos. Once these progenitors orbit their primary systems, they rapidly lose their original mass but not their identifiers. Most of the progenitors are able to survive to present day. At given redshift, the survival fraction of accreted sub-halos is independent of host halo mass, while sub-halos in high mass halos lost more mass. In the second part, we use a semi-analytical galaxy formation model compiled on a Millennium Simulation to study the size evolution of massive early-type galaxies from redshift z = 2 to present days. We find that the model we used is able to well reproduce the amplitude and slope of size-mass relation, as well as its evolution. The amplitude of this relation reflects the typical compactness of dark matter halos at the time when most stars are formed. This link between size and star formation epoch is propagated in through galaxy combinations. Minor combinations are increasingly important with increasing present day stellar mass for galaxies more massive than 1011.4M⊙. At lower masses, major combinations are more important. In situ star formation contributes more to the size growth than it does to stellar mass growth. Similar to former works, we find that minor combinations dominate the subsequent growth both in stellar mass and in size for early formed early-type galaxies.

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The role of mergers and interactions in driving the evolution of dwarf galaxies over cosmic time

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3443 ◽

2020 ◽

Vol 500 (4) ◽

pp. 4937-4957 ◽

Cited By ~ 2

Author(s):

G Martin ◽

R A Jackson ◽

S Kaviraj ◽

H Choi ◽

J E G Devriendt ◽

...

Keyword(s):

Star Formation ◽

Dwarf Galaxies ◽

Large Fraction ◽

Structural Evolution ◽

Cosmic Time ◽

Stellar Mass ◽

High Mass ◽

Key Drivers ◽

Mass Assembly

ABSTRACT Dwarf galaxies (M⋆ < 109 M⊙) are key drivers of mass assembly in high-mass galaxies, but relatively little is understood about the assembly of dwarf galaxies themselves. Using the NewHorizon cosmological simulation (∼40 pc spatial resolution), we investigate how mergers and fly-bys drive the mass assembly and structural evolution of around 1000 field and group dwarfs up to z = 0.5. We find that, while dwarf galaxies often exhibit disturbed morphologies (5 and 20 per cent are disturbed at z = 1 and z = 3 respectively), only a small proportion of the morphological disturbances seen in dwarf galaxies are driven by mergers at any redshift (for 109 M⊙, mergers drive under 20 per cent morphological disturbances). They are instead primarily the result of interactions that do not end in a merger (e.g. fly-bys). Given the large fraction of apparently morphologically disturbed dwarf galaxies which are not, in fact, merging, this finding is particularly important to future studies identifying dwarf mergers and post-mergers morphologically at intermediate and high redshifts. Dwarfs typically undergo one major and one minor merger between z = 5 and z = 0.5, accounting for 10 per cent of their total stellar mass. Mergers can also drive moderate star formation enhancements at lower redshifts (3 or 4 times at z = 1), but this accounts for only a few per cent of stellar mass in the dwarf regime given their infrequency. Non-merger interactions drive significantly smaller star formation enhancements (around two times), but their preponderance relative to mergers means they account for around 10 per cent of stellar mass formed in the dwarf regime.

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Correlations between H α equivalent width and galaxy properties at z = 0.47: Physical or selection-driven?

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab778 ◽

2021 ◽

Vol 503 (4) ◽

pp. 5115-5133

Author(s):

A A Khostovan ◽

S Malhotra ◽

J E Rhoads ◽

S Harish ◽

C Jiang ◽

...

Keyword(s):

Star Formation ◽

Equivalent Width ◽

Luminosity Function ◽

Mass Function ◽

Stellar Mass ◽

High Mass ◽

Selection Effects ◽

Star Formation Activity ◽

Low Mass ◽

Stellar Masses

ABSTRACT The H α equivalent width (EW) is an observational proxy for specific star formation rate (sSFR) and a tracer of episodic, bursty star-formation activity. Previous assessments show that the H α EW strongly anticorrelates with stellar mass as M−0.25 similar to the sSFR – stellar mass relation. However, such a correlation could be driven or even formed by selection effects. In this study, we investigate how H α EW distributions correlate with physical properties of galaxies and how selection biases could alter such correlations using a z = 0.47 narrow-band-selected sample of 1572 H α emitters from the Ly α Galaxies in the Epoch of Reionization (LAGER) survey as our observational case study. The sample covers a 3 deg2 area of COSMOS with a survey comoving volume of 1.1 × 105 Mpc3. We assume an intrinsic EW distribution to form mock samples of H α emitters and propagate the selection criteria to match observations, giving us control on how selection biases can affect the underlying results. We find that H α EW intrinsically correlates with stellar mass as W0∝M−0.16 ± 0.03 and decreases by a factor of ∼3 from 107 M⊙ to 1010 M⊙, while not correcting for selection effects steepens the correlation as M−0.25 ± 0.04. We find low-mass H α emitters to be ∼320 times more likely to have rest-frame EW>200 Å compared to high-mass H α emitters. Combining the intrinsic W0–stellar mass correlation with an observed stellar mass function correctly reproduces the observed H α luminosity function, while not correcting for selection effects underestimates the number of bright emitters. This suggests that the W0–stellar mass correlation when corrected for selection effects is physically significant and reproduces three statistical distributions of galaxy populations (line luminosity function, stellar mass function, EW distribution). At lower stellar masses, we find there are more high-EW outliers compared to high stellar masses, even after we take into account selection effects. Our results suggest that high sSFR outliers indicative of bursty star formation activity are intrinsically more prevalent in low-mass H α emitters and not a byproduct of selection effects.

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A general approach to quenching and galactic conformity

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1695 ◽

2019 ◽

Vol 488 (1) ◽

pp. 234-252

Author(s):

Larry P T Sin ◽

Simon J Lilly ◽

Bruno M B Henriques

Keyword(s):

Star Formation ◽

Conceptual Framework ◽

Empirical Model ◽

Local Density ◽

Hidden Variables ◽

Stellar Mass ◽

High Mass ◽

Low Mass ◽

The Difference ◽

Internal Properties

ABSTRACT We develop a conceptual framework and methodology to study the drivers of the quenching of galaxies, including the drivers of galactic conformity. The framework is centred on the statistic Δ, which is defined as the difference between the observed star formation state of a galaxy, and a prediction of its state based on an empirical model of quenching. In particular, this work uses the average quenching effects of stellar mass M* and local density δ to construct an empirical model of quenching. Δ is therefore a residual which reflects the effects of drivers of quenching not captured by M* and δ, or so-called hidden variables. Through a toy model, we explore how the statistical properties of Δ can be used to learn about the internal and external hidden variables which control the quenching of a sample of galaxies. We then apply this analysis to a sample of local galaxies and find that, after accounting for the average quenching effects of M* and δ, Δ remains correlated out to separations of 3 Mpc. Furthermore, we find that external hidden variables remain important for driving the residual quenching of low-mass galaxies, while the residual quenching of high-mass galaxies is driven mostly by internal properties. These results, along with a similar analysis of a semi-analytical mock catalogue, suggest that it is necessary to consider halo-related properties as candidates for hidden variables. A preliminary halo-based analysis indicates that much of the correlation of Δ can be attributed to the physics associated with individual haloes.

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G.A.S.

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834673 ◽

2019 ◽

Vol 627 ◽

pp. A131 ◽

Cited By ~ 4

Author(s):

M. Cousin ◽

P. Guillard ◽

M. D. Lehnert

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Large Scale ◽

Spatial Scales ◽

Turbulent Energy ◽

Stellar Mass ◽

High Mass ◽

Radiative Cooling ◽

The Impact ◽

Good Agreement

Context. Star formation in galaxies is inefficient, and understanding how star formation is regulated in galaxies is one of the most fundamental challenges of contemporary astrophysics. Radiative cooling, feedback from supernovae and active galactic nuclei (AGN), and large-scale dynamics and dissipation of turbulent energy act over various time and spatial scales and all regulate star formation in a complex gas cycle. Aims. This paper presents the physics implemented in a new semi-analytical model of galaxy formation and evolution called the Galaxy Assembler from dark-matter Simulation (G.A.S.). Methods. The fundamental underpinning of our new model is the development of a multiphase interstellar medium (ISM) in which energy produced by supernovae and AGN maintains an equilibrium between a diffuse, hot, and stable gas and a cooler, clumpy, and low-volume filling factor gas. The hot gas is susceptible to thermal and dynamical instabilities. We include a description of how turbulence leads to the formation of giant molecular clouds through an inertial turbulent energy cascade, assuming a constant kinetic energy transfer per unit volume. We explicitly modelled the evolution of the velocity dispersion at different scales of the cascade and accounted for thermal instabilities in the hot halo gas. Thermal instabilities effectively reduce the impact of radiative cooling and moderates accretion rates onto galaxies, and in particular, for those residing in massive haloes. Results. We show that rapid and multiple exchanges between diffuse and unstable gas phases strongly regulates star formation rates in galaxies because only a small fraction of the unstable gas is forming stars. We checked that the characteristic timescales describing the gas cycle, gas depletion timescale, and star-forming laws at different scales are in good agreement with observations. For high-mass haloes and galaxies, cooling is naturally regulated by the growth of thermal instabilities, so we do not need to implement strong AGN feedback in this model. Our results are also in good agreement with the observed stellar mass function from z ≃ 6.0 to z ≃ 0.5. Conclusion. Our model offers the flexibility to test the impact of various physical processes on the regulation of star formation on a representative population of galaxies across cosmic times. Thermal instabilities and the cascade of turbulent energy in the dense gas phase introduce a delay between gas accretion and star formation, which keeps galaxy growth inefficient in the early Universe. The main results presented in this paper, such as stellar mass functions, are available in the GALAKSIENN library.

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Galaxy kinematics across different environments in the RXJ1347−1145 cluster complex

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936243 ◽

2020 ◽

Vol 637 ◽

pp. A30

Author(s):

J. M. Pérez-Martínez ◽

B. Ziegler ◽

A. Böhm ◽

M. Verdugo

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Formation Rate ◽

Stellar Mass ◽

Cluster Complex ◽

Mass Relation ◽

Cluster Membership ◽

Cluster Galaxies ◽

Fisher Relation

Aims. In order to understand the role of the different processes that drive galaxy evolution in clusters, we need comprehensive studies that simultaneously examine several of the most important physical properties of galaxies. In this work we study the interplay between the kinematic state and star formation activity of galaxies in the RXJ1347−1145 cluster complex at z ∼ 0.45. Methods. We used VLT/VIMOS to obtain slit spectra for 95 galaxies across the 40′ × 40′ area where the RXJ1347−1145 cluster complex resides. We determined the cluster membership of our targets by identifying one or more of the available emission lines within the wavelength range. Our spectroscopy is complemented with archival SUBARU/Suprime-Cam deep photometric observations in five optical bands (B, V, Rc, Ic, z′). We examined the kinematic properties of our sample attending to the degree of distortion of the extracted rotation curves. Regular rotating galaxies were included in our Tully–Fisher analysis while the distorted ones were used to study the role of cluster-specific interactions with respect to star formation and AGN activity. Results. Our analysis confirmed the cluster membership for approximately half of our targets. We report a higher fraction of galaxies with irregular gas kinematics in the cluster environment than in the field. Cluster galaxies with regular rotation display a moderate brightening in the B-band Tully–Fisher relation compatible with the gradual evolution of the stellar populations with lookback time, and no significant evolution in the stellar-mass Tully–Fisher relation, in line with previous studies at similar redshift. Average specific star formation rate values are slightly lower in our cluster sample (−0.15 dex) with respect to the main sequence of star-forming galaxies, confirming the role of the environment in the early quenching of star formation in clusters. Finally, we carried out an exploratory observational study on the stellar-to-halo mass relation finding that cluster galaxies tend to have slightly lower stellar mass values for a fixed halo mass compared to their field counterparts.

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