14 research outputs found
First Light And Reionisation Epoch Simulations (FLARES) VIII. The Emergence of Passive Galaxies at
Passive galaxies are ubiquitous in the local universe, and various physical
channels have been proposed that lead to this passivity. To date, robust
passive galaxy candidates have been detected up to , but it is
still unknown if they exist at higher redshifts, what their relative abundances
are, and what causes them to stop forming stars. We present predictions from
the First Light And Reionisation Epoch Simulations (FLARES), a series of zoom
simulations of a range of overdensities using the EAGLE code. Passive galaxies
occur naturally in the EAGLE model at high redshift, and are in good agreement
with number density estimates from HST and early JWST results at . Due to the unique FLARES approach, we extend these predictions to
higher redshifts, finding passive galaxy populations up to . Feedback
from supermassive black holes is the main driver of passivity, leading to
reduced gas fractions and star forming gas reservoirs. We find that passive
galaxies at are not identified in the typical UVJ selection
space due to their still relatively young stellar populations, and present new
rest--frame selection regions. We also present NIRCam and MIRI fluxes, and find
that significant numbers of passive galaxies at should be
detectable in upcoming wide surveys with JWST. Finally, we present JWST colour
distributions, with new selection regions in the observer--frame for
identifying these early passive populations.Comment: 21 pages, 20 figures. Accepted to MNRA
First Light And Reionisation Epoch Simulations (FLARES) I: environmental dependence of high-redshift galaxy evolution
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 (3.2cGpc)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
The JWST Hubble Sequence: The Rest-frame Optical Evolution of Galaxy Structure at 1.5 < z < 6.5
© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/We present results on the morphological and structural evolution of a total of 3956 galaxies observed with JWST at 1.5 109 M ⊙ at z > 3 are not dominated by irregular and peculiar structures, either visually or quantitatively, as previously thought. We find a strong dominance of morphologically selected disk galaxies up to z = 6 in this mass range. We also find that the stellar mass and star formation rate densities are dominated by disk galaxies up to z ∼ 6, demonstrating that most stars in the Universe were likely formed in a disk galaxy. We compare our results to theory to show that the fraction of types we find is predicted by cosmological simulations, and that the Hubble Sequence was already in place as early as one billion years after the Big Bang. Additionally, we make our visual classifications public for the community.Peer reviewe
Cosmic Evolution Early Release Science (CEERS) survey: The colour evolution of galaxies in the distant Universe
The wavelength-coverage and sensitivity of JWST now enables us to probe the
rest-frame UV - optical spectral energy distributions (SEDs) of galaxies at
high-redshift (). From these SEDs it is, in principle, through SED fitting
possible to infer key physical properties, including stellar masses, star
formation rates, and dust attenuation. These in turn can be compared with the
predictions of galaxy formation simulations allowing us to validate and refine
the incorporated physics. However, the inference of physical properties,
particularly from photometry alone, can lead to large uncertainties and
potential biases. Instead, it is now possible, and common, for simulations to
be \emph{forward-modelled} to yield synthetic observations that can be compared
directly to real observations. In this work, we measure the JWST broadband
fluxes and colours of a robust sample of galaxies using the Cosmic
Evolution Early Release Science (CEERS) Survey. We then analyse predictions
from a variety of models using the same methodology and compare the
NIRCam/F277W magnitude distribution and NIRCam colours with observations. We
find that the predicted and observed magnitude distributions are similar, at
least at the distributions differ somewhat, though our
observed sample size is small and thus susceptible to statistical fluctuations.
Likewise, the predicted and observed colour evolution show broad agreement, at
least at . There is however some disagreement between the observed and
modelled strength of the strong line contribution. In particular all the models
fails to reproduce the F410M-F444W colour at , though, again, the sample
size is small here.Comment: 11 pages, 10 figures, submitted to MNRA
A de novo designed inhibitor of D-Ala-D-Ala ligase from E. coli
Blueprints for an inhibitor: The de novo molecular design program SPROUT was used in conjunction with the X-ray crystal structures of the bacterial enzymes DdlB and VanA to produce a novel enzyme-selective inhibitor template. Following short and efficient synthesis and in keeping with the design predictions, the resulting inhibitor showed useful levels of enzyme-selective inhibition
Florida’s Changing Rainbow: Identifying Emerging Markets Through the Examination of Racial Composition and Demographic Change in Florida
African Americans, Emerging markets, Hispanics, Population,