Related papers: Quasar-Marked Protoclusters and Biased Galaxy Form…
We report the discovery and spectroscopic confirmation of three gravitationally-lensed images of a galaxy at z=3.9 in the background of a distant, rich cluster of galaxies at z=0.83, on the basis of observations with Faint Object Camera And…
We present an investigation of the environment (\approx 600 kpc radius) of a pair of luminous z=4.25 quasars, SDSS J1439-0034 A,B, separated by 33''. An analysis of high-quality Subaru spectra of the quasars suggests that this configuration…
We discuss the structural and morphological properties of galaxies in a z=1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey…
Observations with WFC3/IR on the Hubble Space Telescope and the use of gravitational lensing techniques have facilitated the discovery of galaxies as far back as z ~ 10-12, a truly remarkable achievement. However, this rapid emergence of…
The most luminous quasars at $z > 6$ are suspected to be both highly clustered and reside in the most massive dark matter halos in the early Universe, making them prime targets to search for galaxy overdensities and/or protoclusters. We…
As the densest galaxy environments in the universe, clusters are vital to our understanding of the role that environment plays in galaxy formation and evolution. Unfortunately, the evolution of high-redshift cluster galaxies is poorly…
Protoclusters, which will yield galaxy clusters at lower redshift, can provide valuable information on the formation of galaxy clusters. However, identifying progenitors of galaxy clusters in observations is not an easy task, especially at…
We have examined the orientations of early-type galaxies in the Coma cluster to see whether the well-established tendency for brightest cluster galaxies to share the same major axis orientation as their host cluster also extends to the rest…
Massive, quiescent galaxies are already observed at redshift $z\sim4$, i.e. $\sim$1.5 Gyr after the Big Bang. Current models predict them to be formed via massive, gas-rich mergers at $z>6$. Recent ALMA observations of the cool gas and dust…
We use the stellar-mass-selected catalog from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) in the COSMOS field to study the environments of galaxies via galaxy density and clustering analyses up to $z \sim 2.5$. The…
The formation history of globular clusters (GCs) at redshift $z > 4$ remains an unsolved problem. In this work, we use the cosmological, $N$-body hydrodynamical ``zoom-in'' simulation GigaEris to study the properties and formation of…
The realization that most stars form in clusters, raises the question of whether star/planet formation are influenced by the cluster environment. The stellar density in the most prevalent clusters is the key factor here. Whether dominant…
Recent work has shown that the star formation-density relation -- in which galaxies with low star formation rates are preferentially found in dense environments -- is still in place at z~1, but the situation becomes less clear at higher…
The discovery of gravitationally lensed stellar clusters at high redshift with the James Webb Space Telescope (JWST) has revealed extremely compact, massive star-forming systems in galaxies at $z > 6$, providing a new window into early…
We previously reported a significant clustering of red galaxies (R-K=3.5--6) around the radio-loud quasar B2 1335+28 at z=1.086. In this paper, we establish the existence of a rich cluster at the quasar redshift, and study the properties of…
Context: Understanding galaxy evolution in dense environments, particularly proto-clusters, is crucial for studying mechanisms driving star formation and quenching. Aims: This study examines how two proto-cluster over-densities at 3 < z < 4…
High redshift galaxy clusters have traditionally been a fruitful place to study galaxy evolution. I review various search strategies for finding clusters at z > 1. Most efforts to date have concentrated on the environments of distant AGN. I…
Investigating the processes by which galaxies rapidly build up their stellar mass during the peak of their star formation ($z=2$--$3$) is crucial to advancing our understanding of the assembly of large-scale structures. We report the…
Magnitude-limited galaxy redshift surveys are now providing large samples of galaxies to beyond z=2, while color-selected and emission-line-selected samples are finding galaxies to z=4.7. A broad picture is emerging of galaxy formation…
We present results from a low-resolution spectroscopic survey for 21 galaxy clusters at $0.4 < z < 0.8$ selected from the ESO Distant Cluster Survey. We measured spectra using the low-dispersion prism in IMACS on the Magellan Baade…