scholarly journals First Light And Reionisation Epoch Simulations (FLARES) II: The Photometric Properties of High-Redshift Galaxies

2020 ◽  
Author(s):  
Aswin P Vijayan ◽  
Christopher C Lovell ◽  
Stephen M Wilkins ◽  
Peter A Thomas ◽  
David J Barnes ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Dynamic Range ◽  
High Redshift ◽  
Distribution Functions ◽  
High Redshift Galaxies ◽  
Relative Contribution ◽  
Extinction Model ◽  
Dust Attenuation ◽  
The Impact ◽  
Composite Distribution

Abstract We present the photometric properties of galaxies in the First Light and Reionisation Epoch Simulations (Flares). The simulations trace the evolution of galaxies in a range of overdensities through the Epoch of Reionistion (EoR). With a novel weighting scheme we combine these overdensities, extending significantly the dynamic range of observed composite distribution functions compared to periodic simulation boxes. Flares predicts a significantly larger number of intrinsically bright galaxies, which can be explained through a simple model linking dust-attenuation to the metal content of the interstellar medium, using a line-of-sight (LOS) extinction model. With this model we present the photometric properties of the Flares galaxies for z ∈ [5, 10]. We show that the ultraviolet (UV) luminosity function (LF) matches the observations at all redshifts. The function is fit by Schechter and double power-law forms, with the latter being favoured at these redshifts by the Flares composite UV LF. We also present predictions for the UV continuum slope as well as the attenuation in the UV. The impact of environment on the UV LF is also explored, with the brightest galaxies forming in the densest environments. We then present the line luminosity and equivalent widths of some prominent nebular emission lines arising from the galaxies, finding rough agreement with available observations. We also look at the relative contribution of obscured and unobscured star formation, finding comparable contributions at these redshifts.

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 Connecting observations of the first galaxies and the Epoch of Reionisation

2019 ◽  
Vol 15 (S352) ◽  
pp. 348-348
Author(s):  
Simon Mutch
Keyword(s):  
Power Spectrum ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
Dwarf Galaxies ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
Relative Contribution ◽  
Redshift Galaxy ◽  
Upper Limits ◽  
First Galaxies

AbstractDwarf galaxies are thought to be dominant contributors of ionizing photons during the Epoch of Reionisation (EoR). Our knowledge of the statistics of these high redshift galaxies is constantly improving and will take yet another important step forward with the launch of JWST. At the same time, the upper limits on the EoR 21cm power spectrum are continually falling, with a firm measurement from SKA-low being a certainty in coming years. In order to maximise what we can learn from these two complimentary observational datasets, we need to be able to model them together, self-consistently. In this talk, I will present insights into the connection between galaxy formation and the EoR gained from the DRAGONS suite of semi-analytic and hydrodynamic galaxy formation simulations. Using these we find that the steep faint end slope of the high- redshift galaxy UV luminosity function extends well beyond current observational limits, indicating that only ∼ 50% of the ionising photons available for reionisation have been observed at z < 7. I will also discuss the relative contribution of quasars to reionisation and present constraints on ionising escape fraction models.

scholarly journals The image plane approach to cosmic telescopes

2015 ◽  
Vol 11 (A29B) ◽  
pp. 783-784
Author(s):  
Masamune Oguri
Keyword(s):  
Gravitational Lensing ◽  
Luminosity Function ◽  
High Redshift ◽  
Selection Effect ◽  
Image Plane ◽  
High Redshift Galaxies ◽  
The Public ◽  
Size Evolution ◽  
Redshift Galaxies

AbstractStudies of high-redshift galaxies behind the cores of mass clusters require the correction of gravitational lensing effects. We present our approach to estimate shapes, magnitudes, and the selection effect of high-redshift galaxies in the image plane, which allows us to include not only lensing magnifications but also lensing distortions and image multiplications. For this purpose we construct new mass models for the Frontier Fields clusters using the public software glafic. We present some results on faint-end slopes of the luminosity function and the size evolution of high-redshift galaxies from the analysis of Frontier Fields clusters.

scholarly journals Semi-analytic forecasts for JWST – II. Physical properties and scaling relations for galaxies at z = 4–10

2019 ◽  
Vol 490 (2) ◽  
pp. 2855-2879 ◽  
Author(s):  
L Y Aaron Yung ◽  
Rachel S Somerville ◽  
Gergö Popping ◽  
Steven L Finkelstein ◽  
Harry C Ferguson ◽  
...  
Keyword(s):  
Star Formation ◽  
Physical Properties ◽  
High Redshift ◽  
Formation Rate ◽  
Distribution Functions ◽  
Scaling Relations ◽  
Physical Parameters ◽  
Model Parameters ◽  
Galaxy Populations ◽  
The Impact

ABSTRACT The long anticipated James Webb Space Telescope (JWST) will be able to directly detect large samples of galaxies at very high redshift. Using the well-established, computationally efficient Santa Cruz semi-analytic model, with recently implemented multiphase gas partitioning, and H2-based star formation recipes, we make predictions for a wide variety of galaxy properties for galaxy populations at z = 4–10. In this work, we provide forecasts for the physical properties of high-redshift galaxies and links to their photometric properties. With physical parameters calibrated only to z ∼ 0 observations, our model predictions are in good agreement with current observational constraints on stellar mass and star formation rate distribution functions up to z ∼ 8. We also provide predictions representing wide, deep, and lensed JWST survey configurations. We study the redshift evolution of key galaxy properties and the scaling relations among them. Taking advantage of our models’ high computational efficiency, we study the impact of systematically varying the model parameters. All distribution functions and scaling relations presented in this work are available at https://www.simonsfoundation.org/semi-analytic-forecasts-for-jwst/.

scholarly journals High-redshift JWST predictions from IllustrisTNG: II. Galaxy line and continuum spectral indices and dust attenuation curves

2020 ◽  
Vol 495 (4) ◽  
pp. 4747-4768 ◽  
Author(s):  
Xuejian Shen ◽  
Mark Vogelsberger ◽  
Dylan Nelson ◽  
Annalisa Pillepich ◽  
Sandro Tacchella ◽  
...  
Keyword(s):  
High Redshift ◽  
Formation Rate ◽  
Spectral Indices ◽  
High Redshift Galaxies ◽  
Luminosity Functions ◽  
Galaxy Populations ◽  
Stellar Masses ◽  
Red Galaxies ◽  
Dust Attenuation ◽  
Rate Relation

ABSTRACT We present predictions for high redshift (z = 2−10) galaxy populations based on the IllustrisTNG simulation suite and a full Monte Carlo dust radiative transfer post-processing. Specifically, we discuss the H α and H β + $[\rm O \,{\small III}]$ luminosity functions up to z = 8. The predicted H β + $[\rm O \,{\small III}]$ luminosity functions are consistent with present observations at z ≲ 3 with ${\lesssim} 0.1\, {\rm dex}$ differences in luminosities. However, the predicted H α luminosity function is ${\sim }0.3\, {\rm dex}$ dimmer than the observed one at z ≃ 2. Furthermore, we explore continuum spectral indices, the Balmer break at 4000 Å; (D4000) and the UV continuum slope β. The median D4000 versus specific star formation rate relation predicted at z = 2 is in agreement with the local calibration despite a different distribution pattern of galaxies in this plane. In addition, we reproduce the observed AUV versus β relation and explore its dependence on galaxy stellar mass, providing an explanation for the observed complexity of this relation. We also find a deficiency in heavily attenuated, UV red galaxies in the simulations. Finally, we provide predictions for the dust attenuation curves of galaxies at z = 2−6 and investigate their dependence on galaxy colours and stellar masses. The attenuation curves are steeper in galaxies at higher redshifts, with bluer colours, or with lower stellar masses. We attribute these predicted trends to dust geometry. Overall, our results are consistent with present observations of high-redshift galaxies. Future James Webb Space Telecope observations will further test these predictions.

scholarly journals A PHYSICAL MODEL FOR THE EVOLVING ULTRAVIOLET LUMINOSITY FUNCTION OF HIGH REDSHIFT GALAXIES AND THEIR CONTRIBUTION TO THE COSMIC REIONIZATION

2014 ◽  
Vol 785 (1) ◽  
pp. 65 ◽  
Author(s):  
Zhen-Yi Cai ◽  
Andrea Lapi ◽  
Alessandro Bressan ◽  
Gianfranco De Zotti ◽  
Mattia Negrello ◽  
...  
Keyword(s):  
Physical Model ◽  
Luminosity Function ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
Redshift Galaxies

scholarly journals Shedding light on high-redshift galaxies with the 21cm signal

2019 ◽  
Vol 15 (S352) ◽  
pp. 69-69
Author(s):  
Anne Hutter
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Neutral Hydrogen ◽  
First Stars ◽  
High Redshift Galaxies ◽  
Redshift Galaxy ◽  
First Galaxies ◽  
Galaxy Population ◽  
The Impact ◽  
Redshift Galaxies

AbstractReionization represents an important epoch in the history in the Universe, when the first stars and galaxies gradually ionize the neutral hydrogen in the intergalactic medium (IGM). Understanding the nature of the ionizing sources, the associated ionization of the IGM, and its impact on subsequent structure formation and galaxy evolution by means of radiative feedback effects, represent key outstanding questions in current astrophysics. High-redshift galaxy observations and simulations have significantly extended our knowledge on the nature of high-redshift galaxies. However, essential properties such as the escape fraction of ionizing photons from galaxies into the IGM and their dependency on galactic properties remain essentially unknown, but determine significantly the distribution and time evolution of the ionized regions during reionization. Analyzing this ionization topology by means of the neutral hydrogen sensitive 21cm signal with radio interferometers such as SKA offers a complementary and unique opportunity to determine the nature of these first galaxies. I will show results from a self-consistent semi-numerical model of galaxy evolution and reionization, and discuss the potential of inferring galactic properties with the 21cm signal as well as the impact of reionization on the high-redshift galaxy population and its evolution.

scholarly journals The impact of binary stars on the colors of high-redshift galaxies

2013 ◽  
Vol 554 ◽  
pp. A136 ◽  
Author(s):  
Y. Zhang ◽  
J. Liu ◽  
F. Zhang ◽  
Z. Han
Keyword(s):  
Binary Stars ◽  
High Redshift ◽  
High Redshift Galaxies ◽  
The Impact ◽  
Redshift Galaxies

scholarly journals The intergalactic medium transmission towards z ≳ 4 galaxies with VANDELS and the impact of dust attenuation

2020 ◽  
Vol 634 ◽  
pp. A110 ◽  
Author(s):  
R. Thomas ◽  
L. Pentericci ◽  
O. Le Fevre ◽  
G. Zamorani ◽  
D. Schaerer ◽  
...  
Keyword(s):  
Intergalactic Medium ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Theoretical Models ◽  
Spectral Energy ◽  
Uv Spectrum ◽  
Star Forming ◽  
Dust Extinction ◽  
Dust Attenuation ◽  
The Impact

Aims. Our aim is to estimate the intergalactic medium (IGM) transmission towards UV-selected star-forming galaxies at z ≳ 4 and study the effect of the dust attenuation on these measurements. Methods. The UV spectrum of high-redshift galaxies is a combination of their intrinsic emission and the effect of the IGM absorption along their line of sight. Using data coming from the unprecedentedly deep spectroscopy from the VANDELS ESO public survey carried out with the VIMOS instrument, we compute both the dust extinction and the mean transmission of the IGM as well as its scatter from a set of 281 galaxies at z >  3.87. Because of a degeneracy between the dust content of the galaxy and the IGM, we first estimate the stellar dust extinction parameter E(B − V) and study the result as a function of the dust prescription. Using these measurements as constraint for the spectral fit we estimate the IGM transmission Tr(Lyα). Both photometric and spectroscopic spectral energy distribution fits are performed using the SPectroscopy And photometRy fiTting tool for Astronomical aNalysis which is able to fit the spectral continuum of the galaxies as well as photometric data. Results. Using the classical Calzetti attenuation law we find that E(B − V) goes from 0.11 at z = 3.99 to 0.08 at z = 5.15. These results are in very close agreement with published measurements. We estimate the IGM transmission and find that the transmission is decreasing with increasing redshift from Tr(Lyα) = 0.53 at z = 3.99 to 0.28 at z = 5.15. We also find a large standard deviation around the average transmission that is more than 0.1 at every redshift. Our results are in very good agreement with both previous measurements from AGN studies and with theoretical models.

scholarly journals High-redshift JWST predictions from IllustrisTNG: dust modelling and galaxy luminosity functions

2020 ◽  
Vol 492 (4) ◽  
pp. 5167-5201 ◽  
Author(s):  
Mark Vogelsberger ◽  
Dylan Nelson ◽  
Annalisa Pillepich ◽  
Xuejian Shen ◽  
Federico Marinacci ◽  
...  
Keyword(s):  
Observational Data ◽  
Exposure Time ◽  
Cold Dark Matter ◽  
Rest Frame ◽  
Dynamic Range ◽  
High Redshift ◽  
Formation Rate ◽  
Mass Relation ◽  
Luminosity Functions ◽  
Dust Attenuation

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 $10^4\, {\rm s}$.

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