galaxies

Red riding on hood: Exploring how galaxy colour depends on environment

First author: Pankaj C. Bhambhani Galaxy populations are known to exhibit a strong colour bimodality, corresponding to blue star-forming and red quiescent subpopulations. The relative abundance of the two populations has been found to vary with stellar mass and environment. In this paper, we explore the effect of environment considering different types of measurements. We choose a sample of 49, 911 galaxie with $0.05 < z < 0.18$ from the Galaxy And Mass Assembly survey.

Self-calibrating optical galaxy cluster selection bias using cluster, galaxy, and shear cross-correlations

First author: Chenxiao Zeng The clustering signals of galaxy clusters are known to be powerful tools for self-calibrating the mass-observable relation and are complementary to cluster abundance and lensing. In this work, we explore the possibility of combining three correlation functions – cluster lensing, the cluster-galaxy cross-correlation function, and the galaxy auto-correlation function – to self-calibrate optical cluster selection bias, the boosted clustering and lensing signals in a richness-selected sample mainly caused by projection effects.

A shot in the Dark (Ages): a faint galaxy at $z=9.76$ confirmed with JWST

First author: Guido Roberts-Borsani The appearance of galaxies over the first billion years after the Big Bang is believed to be responsible for the last dramatic change in the state of the Universe. Ultraviolet photons from galaxies within this time period - the Epoch of Reionization - ionized intergalactic Hydrogen, rendering the Universe transparent to UV radiation and ending the so-called cosmic Dark Ages, sometime after redshift $z\sim8$. The majority of ionizing photons in the first few hundred Myrs of cosmic history are thought to derive from galaxies significantly fainter than the characteristic luminosity $L^{}$.

Effects of feedback on galaxies in the VELA simulations: elongation, clumps and compaction

First author: Daniel Ceverino The evolution of star-forming galaxies at high redshifts is very sensitive to the strength and nature of stellar feedback. Using two sets of cosmological, zoom-in simulations from the VELA suite, we compare the effects of two different models of feedback: with and without kinetic feedback. At a fixed halo mass and redshift, the stellar mass is reduced by a factor of 1-3 in the models with stronger feedback, so the stellar-mass-halo-mass relation is in better agreement with abundance matching results.

Kinematics of the Local Group gas and galaxies in the Hestia simulations

First author: Luis Biaus We investigate the kinematic properties of gas and galaxies in the Local Group (LG) using high-resolution simulations performed by the {\sc Hestia} (High-resolution Environmental Simulations of The Immediate Area) collaboration. Our simulations include the correct cosmography surrounding LG-like regions consisting of two main spiral galaxies of $\sim 10^{12}$~M$_\odot$, their satellites and minor isolated galaxies, all sharing the same large-scale motion within a volume of a few Mpc.

Properties of Globular Clusters in Galaxy Clusters: Sensitivity from the Formation and Evolution of Globular Clusters

First author: So-Myoung Park We investigate the properties of globular clusters in a galaxy cluster, using the particle tagging method with a semi-analytical approach in a cosmological context. We assume globular clusters form from dark matter halo mergers and their metallicity is assigned based on the stellar mass of the host dark matter halos and the formation redshift of GCs. Dynamical evolution and disruption of globular clusters are considered using semi-analytical approaches, controlled by several free parameters.

Quasi-stellar objects and galaxy mass density profiles derived using the submillimetre galaxies magnification bias

First author: D. Crespo In this work, we want to exploit the magnification bias of the SMGs using two different foreground samples, quasi-stellar objects (QSOs) and galaxies. Our aim is to study and compare their mass density profiles and estimate their masses and concentrations. The background SMG sample consists of objects observed by \textit{Herschel} with 1.2<z<4.0. The foreground samples are QSOs and massive galaxies with spectroscopic redshifts between 0.2 and 1.

Spectroscopy from Lyman alpha to [O III] 5007 of a Triply Imaged Magnified Galaxy at Redshift z = 9.5

First author: Hayley Williams Given their extremely faint apparent brightness, the nature of the first galaxies and how they reionized the Universe’s gas are not yet understood. Here we report the discovery, in James Webb Space Telescope (JWST) imaging, of a highly magnified, low-mass (log(M_*/M_sol)=7.70^{+0.11}{-0.09}) galaxy visible when the Universe was only 510 Myr old, and follow-up prism spectroscopy of the galaxy extending from Lyman alpha to [O III] 5007 in its rest frame.

Beyond Ultra-Diffuse Galaxies I: Mass-Size Outliers Among the Satellites of Milky Way Analogs

First author: Jiaxuan Li Large diffuse galaxies are hard to find, but understanding the environments where they live, their numbers, and ultimately their origins, is of intense interest and importance for galaxy formation and evolution. Using Subaru’s Hyper Suprime-Cam Strategic Survey Program, we perform a systematic search for low surface brightness galaxies and present novel and effective methods for detecting and modeling them. As a case study, we surveyed 922 Milky Way analogs in the nearby Universe ($0.

CEERS Key Paper IV: The Diversity of Galaxy Structure and Morphology at z=3-9 with JWST

First author: Jeyhan S. Kartaltepe We present a comprehensive analysis of the evolution of the morphological and structural properties of a large sample of galaxies at z=3-9 using early JWST CEERS NIRCam observations. Our sample consists of 850 galaxies at z>3 detected in both CANDELS HST imaging and JWST CEERS NIRCam images to enable a comparison of HST and JWST morphologies. Our team conducted a set of visual classifications, with each galaxy in the sample classified by three different individuals.