scholarly journals Assessing the Predictive Power of Galaxy Formation Models: A Comparison of Predicted and Observed Rest-Frame Optical Luminosity Functions at [FORMULA][F]2.0≤z≤3.3[/F][/FORMULA]

2007 ◽  
Vol 663 (2) ◽  
pp. L89-L92 ◽  
Author(s):  
Danilo Marchesini ◽  
Pieter G. van Dokkum
2006 ◽  
Vol 2 (S238) ◽  
pp. 65-70
Author(s):  
Andrea Merloni ◽  
Sebastian Heinz

AbstractWe present a first attempt to derive the cosmological evolution of the kinetic luminosity function of AGN based on the joint evolution of the flat spectrum radio and hard X-ray selected AGN luminosity functions. An empirical correlation between jet power and radio core luminosity is found, which is consistent with the theoretical assumption that, below a certain Eddington ratio, SMBH accrete in a radiatively inefficient way, while most of the energy output is in the form of kinetic energy.We show how the redshift evolution of the kinetic power density from such a low-ṁ mode of accretion makes it a good candidate to explain the so-called “radio mode” of AGN feedback as outlined in many galaxy formation schemes.


2020 ◽  
Vol 493 (2) ◽  
pp. 2782-2792
Author(s):  
Eda Gjergo ◽  
Marco Palla ◽  
Francesca Matteucci ◽  
Elena Lacchin ◽  
Andrea Biviano ◽  
...  

ABSTRACT Stacked analyses of galaxy clusters at low-to-intermediate redshift show signatures attributable to dust, but the origin of this dust is uncertain. We test the hypothesis that the bulk of cluster dust derives from galaxy ejecta. To do so, we employ dust abundances obtained from detailed chemical evolution models of galaxies. We integrate the dust abundances over cluster luminosity functions (one-slope and two-slope Schechter functions). We consider both a hierarchical scenario of galaxy formation and an independent evolution of the three main galactic morphologies: elliptical/S0, spiral and irregular. We separate the dust residing within galaxies from the dust ejected in the intracluster medium. To the latter, we apply thermal sputtering. The model results are compared to low-to-intermediate redshift observations of dust masses. We find that in any of the considered scenarios, elliptical/S0 galaxies contribute negligibly to the present-time intracluster dust, despite producing the majority of gas-phase metals in galaxy clusters. Spiral galaxies, instead, provide both the bulk of the spatially unresolved dust and of the dust ejected into the intracluster medium. The total dust-to-gas mass ratio in galaxy clusters amounts to 10−4, while the intracluster medium dust-to-gas mass ratio amounts to 10−6 at most. These dust abundances are consistent with the estimates of cluster observations at 0.2 < z < 1. We propose that galactic sources, spiral galaxies in particular, are the major contributors to the cluster dust budget.


2010 ◽  
Vol 6 (S277) ◽  
pp. 282-286
Author(s):  
Lidia A. M. Tasca ◽  
Laurence Tresse ◽  

AbstractThe chronology of galactic bulge and disk formation is studied by analysing the relative contributions of these components to the B band rest–frame luminosity density (LD) at two different cosmological epochs. The luminosity function (LF) of the bulge and disk components at z ~ 0.8 is computed on a galaxy subsample of the final zCOSMOS “bright” catalogue of roughly 20,000 objects with spectroscopic redshift in the COSMOS field. The comparison is then performed on galaxies in the local universe. Our preliminary results show that the LD in the disk component strongly decreases from ~ 80% at z ~ 0.8 to ~ 50% at z = 0, the bulges having a specular behaviour. The observational constraints provided in this work are aimed to discriminate among competing scenarios of galaxy formation and evolution. An appropriate comparison with hydrodynamical semianalytical models will be considered in a future study to understand further the formation and evolution of galaxies.


2020 ◽  
Vol 499 (3) ◽  
pp. 4534-4544 ◽  
Author(s):  
Jordan Mirocha

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.


1994 ◽  
Vol 161 ◽  
pp. 649-651
Author(s):  
K. Rakos ◽  
J. Schombert ◽  
T. Maindl ◽  
N. Unger ◽  
P. Obitsch

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 < 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 & 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.


2020 ◽  
Vol 634 ◽  
pp. A97 ◽  
Author(s):  
Y. Khusanova ◽  
O. Le Fèvre ◽  
P. Cassata ◽  
O. Cucciati ◽  
B. C. Lemaux ◽  
...  

Context. The star formation rate density (SFRD) evolution presents an area of great interest in the studies of galaxy evolution and reionization. The current constraints of SFRD at z >  5 are based on the rest-frame UV luminosity functions with the data from photometric surveys. The VIMOS UltraDeep Survey (VUDS) was designed to observe galaxies at redshifts up to ∼6 and opened a window for measuring SFRD at z >  5 from a spectroscopic sample with a well-controlled selection function. Aims. We establish a robust statistical description of the star-forming galaxy population at the end of cosmic HI reionization (5.0 ≤ z ≤ 6.6) from a large sample of 49 galaxies with spectroscopically confirmed redshifts. We determine the rest-frame UV and Lyα luminosity functions and use them to calculate SFRD at the median redshift of our sample z = 5.6. Methods. We selected a sample of galaxies at 5.0 ≤ zspec ≤ 6.6 from the VUDS. We cleaned our sample from low redshift interlopers using ancillary photometric data. We identified galaxies with Lyα either in absorption or in emission, at variance with most spectroscopic samples in the literature where Lyα emitters (LAE) dominate. We determined luminosity functions using the 1/Vmax method. Results. The galaxies in this redshift range exhibit a large range in their properties. A fraction of our sample shows strong Lyα emission, while another fraction shows Lyα in absorption. UV-continuum slopes vary with luminosity, with a large dispersion. We find that star-forming galaxies at these redshifts are distributed along the main sequence in the stellar mass vs. SFR plane, described with a slope α = 0.85 ± 0.05. We report a flat evolution of the specific SFR compared to lower redshift measurements. We find that the UV luminosity function is best reproduced by a double power law, while a fit with a Schechter function is only marginally inferior. The Lyα luminosity function is best fitted with a Schechter function. We derive a logSFRDUV(M⊙ yr−1 Mpc−3) = −1.45+0.06−0.08 and logSFRDLyα(M⊙ yr−1 Mpc−3) = −1.40+0.07−0.08. The SFRD derived from the Lyα luminosity function is in excellent agreement with the UV-derived SFRD after correcting for IGM absorption. Conclusions. Our new SFRD measurements at a mean redshift of z = 5.6 are ∼0.2 dex above the mean SFRD reported in Madau & Dickinson (2014, ARA&A, 52, 415), but in excellent agreement with results from Bouwens et al. (2015a, ApJ, 803, 34). These measurements confirm the steep decline of the SFRD at z >  2. The bright end of the Lyα luminosity function has a high number density, indicating a significant star formation activity concentrated in the brightest LAE at these redshifts. LAE with equivalent width EW > 25 Å contribute to about 75% of the total UV-derived SFRD. While our analysis favors low dust content in 5.0 <  z <  6.6, uncertainties on the dust extinction correction and associated degeneracy in spectral fitting will remain an issue, when estimating the total SFRD until future surveys extending spectroscopy to the NIR rest-frame spectral domain, such as with JWST.


2020 ◽  
Vol 492 (4) ◽  
pp. 5167-5201 ◽  
Author(s):  
Mark Vogelsberger ◽  
Dylan Nelson ◽  
Annalisa Pillepich ◽  
Xuejian Shen ◽  
Federico Marinacci ◽  
...  

ABSTRACT The James Webb Space Telescope (JWST) promises to revolutionize our understanding of the early Universe, and contrasting its upcoming observations with predictions of the Λ cold dark matter model requires detailed theoretical forecasts. Here, we exploit the large dynamic range of the IllustrisTNG simulation suite, TNG50, TNG100, and TNG300, to derive multiband galaxy luminosity functions from z = 2 to z = 10. We put particular emphasis on the exploration of different dust attenuation models to determine galaxy luminosity functions for the rest-frame ultraviolet (UV), and apparent wide NIRCam bands. Our most detailed dust model is based on continuum Monte Carlo radiative transfer calculations employing observationally calibrated dust properties. This calibration results in constraints on the redshift evolution of the dust attenuation normalization and dust-to-metal ratios yielding a stronger redshift evolution of the attenuation normalization compared to most previous theoretical studies. Overall we find good agreement between the rest-frame UV luminosity functions and observational data for all redshifts, also beyond the regimes used for the dust model calibrations. Furthermore, we also recover the observed high-redshift (z = 4–6) UV luminosity versus stellar mass relation, the H α versus star formation rate relation, and the H α luminosity function at z = 2. The bright end (MUV &gt; −19.5) cumulative galaxy number densities are consistent with observational data. For the F200W NIRCam band, we predict that JWST will detect ∼80 (∼200) galaxies with a signal-to-noise ratio of 10 (5) within the NIRCam field of view, $2.2\times 2.2 \, {\rm arcmin}^{2}$, for a total exposure time of $10^5\, {\rm s}$ in the redshift range z = 8 ± 0.5. These numbers drop to ∼10 (∼40) for an exposure time of $10^4\, {\rm s}$.


2020 ◽  
Vol 498 (2) ◽  
pp. 2645-2661 ◽  
Author(s):  
Jordan Mirocha ◽  
Charlotte Mason ◽  
Daniel P Stark

ABSTRACT Connecting the observed rest-ultraviolet (UV) luminosities of high-z galaxies to their intrinsic luminosities (and thus star formation rates, SFRs) requires correcting for the presence of dust. We bypass a common dust-correction approach that uses empirical relationships between infrared (IR) emission and UV colours, and instead augment a semi-empirical model for galaxy formation with a simple – but self-consistent – dust model and use it to jointly fit high-z rest-UV luminosity functions (LFs) and colour–magnitude relations (MUV–β). In doing so, we find that UV colours evolve with redshift (at fixed UV magnitude), as suggested by observations, even in cases without underlying evolution in dust production, destruction, absorption, or geometry. The observed evolution in our model arises due to the reduction in the mean stellar age and rise in specific SFRs with increasing z. The UV extinction, AUV, evolves similarly with redshift, though we find a systematically shallower relation between AUV and MUV than that predicted by IRX–β relationships derived from z ∼ 3 galaxy samples. Finally, assuming that high $1600\hbox{-}{\mathring{\rm A}}$ transmission (≳0.6) is a reliable Ly α emitter (LAE) indicator, modest scatter in the effective dust surface density of galaxies can explain the evolution both in MUV–β and LAE fractions. These predictions are readily testable by deep surveys with the James Webb Space Telescope.


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