Related papers: DEIMOS spectroscopy of $z=6$ protocluster candidat…
We conduct a systematic search for protocluster candidates at $z \geq 6$ in the COSMOS field using the recently released COSMOS2020 source catalog. We select galaxies using a number of selection criteria to obtain a sample of galaxies that…
We present the discovery of three protoclusters at $z\sim3\mathrm{-}4$ with spectroscopic confirmation in the Canada-France-Hawaii Telescope (CFHT) Legacy Survey Deep Fields. In these fields, we investigate the large-scale projected sky…
We performed a systematic spectroscopic observation of a protocluster at $z=6.01$ in the Subaru Deep Field. We took spectroscopy for all 53 $i'$-dropout galaxies down to $z'=27.09\,\mathrm{mag}$ in/around the protocluster region. From these…
We present new observations of the field containing the z=3.786 protocluster, PC217.96+32.3. We confirm that it is one of the largest and most overdense high-redshift structures known. Such structures are rare even in the largest…
We present a catalog of 10718 objects in the COSMOS field observed through multi-slit spectroscopy with the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope in the wavelength range ~5500-9800A. The catalog contains…
[Abridged] We present the results of a large program conducted with the Very Large Telescope and Keck telescope to search for forming clusters of galaxies near powerful radio galaxies at 2.0 < z < 5.2. We obtained narrow- and broad-band…
High-redshift protoclusters are crucial for understanding the formation of galaxy clusters and the evolution of galaxies in dense environments. The James Webb Space Telescope (JWST), with its unprecedented near-infrared sensitivity, enables…
We identify 42 candidate groups lying between 1.8<z<3.0 from a sample of 3502 galaxies with spectroscopic redshifts in the zCOSMOS-deep redshift survey within the same redshift interval. These systems contain three to five spectroscopic…
Protoclusters represent sites of accelerated galaxy formation and extreme astrophysical activity characteristic of dense environments. Identifying massive protoclusters and mapping their spatial structures are therefore crucial first steps…
We compare the highly clustered populations of very high redshift galaxies with proto-clusters identified numerically in a standard $\Lambda$CDM universe ($\Omega_0=0.3, \lambda_0=0.7$) simulation. We evolve 256^3 dark matter particles in a…
In the hierarchical theory of galaxy formation, a galaxy overdensity is a hallmark of a massive cosmic structure. However, it is less well understood how different types of galaxies trace the underlying large-scale structure. Motivated by…
[Abridged] We characterise a massive proto-cluster at z=2.895 that we found in the COSMOS field using the spectroscopic sample of the VIMOS Ultra-Deep Survey (VUDS). This is one of the rare structures at z~3 not identified around AGNs or…
We have obtained three-dimensional maps of the universe in $\sim200\times200\times80$ comoving Mpc$^3$ (cMpc$^3$) volumes each at $z=5.7$ and $6.6$ based on a spectroscopic sample of 179 galaxies that achieves $\gtrsim80$\% completeness…
Using moderate-resolution optical spectra from 58 background Lyman-break galaxies and quasars at $z\sim 2.3-3$ within a $11.5'\times13.5'$ area of the COSMOS field ($\sim 1200\,\mathrm{deg}^2$ projected area density or $\sim…
We report the discovery of a protocluster at z~6 containing at least eight cluster member galaxies with spectroscopic confirmations in the wide-field image of the Subaru Deep Field (SDF). The overdensity of the protocluster is significant…
Motivated by recent observational studies of the environment of z~6 QSOs, we have used the Millennium Run (MR) simulations to construct a very large (~20 deg^2) mock redshift survey of star-forming galaxies at z~6. We use this simulated…
Protoclusters of galaxies have been found in the last quarter century. However, most of them have been found through the overdensity of star-forming galaxies, and there had been no known structures identified by multiple spectroscopically…
To demonstrate the feasibility of studying the epoch of massive galaxy cluster formation in a more systematic manner using current and future galaxy surveys, we report the discovery of a large sample of proto-cluster candidates in the 1.62…
(Abridged) We have observed CS and C17O lines, and 1.2 mm cont. emission towards a sample of 130 high-mass protostellar candidates with DEC<-30 deg. This is the first step of the southern extension of a project started more than a decade…
We investigate the sky distribution of z ~ 6 Lyman break galaxies selected as i'-dropouts having i' - z' > 1.45 down to z' < 26.5 in the Subaru Deep Field (SDF). We discover 37 i'-dropouts clustered in a projected comoving 21.6 x 21.6 Mpc^2…