Search

We present six spectroscopically confirmed massive protostructures, spanning a redshift range of 2.5 < z < 4.5 in the Extended Chandra Deep Field South (ECDFS) field discovered as part of the Charting Cluster Construction in VUDS and ORELSE (C3VO) survey. We identify and characterize these remarkable systems by applying an overdensity measurement technique on an extensive data compilation of public and proprietary spectroscopic and photometric observations in this highly studied extragalactic field. Each of these six protostructures, i.e. a large scale overdensity (volume >9000 cMpc3) of more than 2.5σδ above the field density levels at these redshifts, have a total mass M tot ≥ 1014.8 M⊙ and one or more highly overdense (overdensity |$\, \gt 5\sigma _{\delta }$|⁠) peaks. One of the most complex protostructures discovered is a massive (M tot = 1015.1M⊙) system at z ∼ 3.47 that contains six peaks and 55 spectroscopic members. We also discover protostructures at z ∼ 3.30 and z ∼ 3.70 that appear to at least partially overlap on sky with the protostructure at z ∼ 3.47, suggesting a possible connection. We additionally report on the discovery of three massive protostructures at z  = 2.67, 2.80, and 4.14 and discuss their properties. Finally, we discuss the relationship between star formation rate and environment in the richest of these protostructures, finding an enhancement of star formation activity in the densest regions. The diversity of the protostructures reported here provide an opportunity to study the complex effects of dense environments on galaxy evolution over a large redshift range in the early Universe. [ABSTRACT FROM AUTHOR]

Simulations predict that the galaxy populations inhabiting protoclusters may contribute considerably to the total amount of stellar mass growth of galaxies in the early universe. In this study, we test these predictions observationally, using the Taralay protocluster (formerly PCl J1001+0220) at z ∼ 4.57 in the COSMOS field. With the Charting Cluster Construction with VUDS and ORELSE (C3VO) survey, we spectroscopically confirmed 44 galaxies within the adopted redshift range of the protocluster (4.48 < z < 4.64) and incorporate an additional 18 galaxies from ancillary spectroscopic surveys. Using a density mapping technique, we estimate the total mass of Taralay to be ∼1.7 × 1015 M⊙, sufficient to form a massive cluster by the present day. By comparing the star formation rate density (SFRD) within the protocluster (SFRDpc) to that of the coeval field (SFRDfield), we find that SFRDpc surpasses the SFRDfield by Δlog (SFRD/M⊙yr−1 Mpc−3) = 1.08 ± 0.32 (or ∼12 ×). The observed contribution fraction of protoclusters to the cosmic SFRD adopting Taralay as a proxy for typical protoclusters is |$33.5~{{\ \rm per\ cent}}^{+8.0~{{\ \rm per\ cent}}}_{-4.3~{{\ \rm per\ cent}}}$|⁠ , a value ∼2σ higher than the predictions from simulations. Taralay contains three peaks that are 5σ above the average density at these redshifts. Their SFRD is ∼0.5 dex higher than the value derived for the overall protocluster. We show that 68 per cent of all star formation in the protocluster takes place within these peaks, and that the innermost regions of the peaks encase |$\sim 50~{{\ \rm per\ cent}}$| of the total star formation in the protocluster. This study strongly suggests that protoclusters drive stellar mass growth in the early universe and that this growth may proceed in an inside-out manner. [ABSTRACT FROM AUTHOR]

Motivated by spectroscopic confirmation of three overdense regions in the COSMOS field at z ∼ 3.35, we analyse the uniquely deep multiwavelength photometry and extensive spectroscopy available in the field to identify any further related structure. We construct a three-dimensional density map using the Voronoi tesselation Monte Carlo method and find additional regions of significant overdensity. Here, we present and examine a set of six overdense structures at 3.20 < z < 3.45 in the COSMOS field, the most well-characterized of which, PCl J0959 + 0235, has 80 spectroscopically confirmed members and an estimated mass of 1.35 × 1015 M⊙, and is modelled to virialize at z ∼ 1.5−2.0. These structures contain 10 overdense peaks with >5σ overdensity separated by up to 70 cMpc, suggestive of a proto-supercluster similar to the Hyperion system at z ∼ 2.45. Upcoming photometric surveys with JWST such as COSMOS-Web, and further spectroscopic follow-up will enable more extensive analysis of the evolutionary effects that such an environment may have on its component galaxies at these early times. [ABSTRACT FROM AUTHOR]

Background: Substance use disorder (SUD) is a known barrier to patient-self-management, which can hinder efforts to achieve treatment goals in type 2 diabetes (T2D) when the conditions coexist.Objective: Identify the association between SUD and glycemic control in patients with T2D treated in a primary care setting.Methods: This retrospective cohort study included patients with T2D treated by providers at family medicine clinics at an academic medical center and its affiliated regional sites from January 2014 to October 2019. Study index date was the first A1c recorded when T2D and SUD diagnoses had both been documented in the medical record. Glycemic control, measured by hemoglobin A1c (A1c), was identified at baseline and over a 12-month follow-up period and was compared between SUD and non-SUD patients.Results: Of 9568 included patients with T2D, 468 (4.9%) had a SUD diagnosis. In 237 SUD and 4334 non-SUD patients with A1c data, mean (SD) baseline A1c was 8.2% (2.5) and 7.9% (2.1), respectively (P = 0.043). A1c reduction was statistically greater in SUD patients than non-SUD patients (-0.31% versus -0.06%, respectively; P = 0.015), although the clinical significance is modest. In a multivariable linear regression analysis, follow-up A1c was lower in the SUD versus non-SUD patients (coefficient -0.184, 95% CI -0.358, -0.010; P = 0.038).Conclusions: Patients with T2D and SUD had higher baseline A1c but this difference was minimized over a 12-month follow-up period. Additional research is warranted to determine long-term glycemic control and barriers to attaining and maintaining glycemic control in patients with T2D and SUD. [ABSTRACT FROM AUTHOR]

We present a study of the star formation rate (SFR)–density relation at |$z$| ∼ 0.9 using data drawn from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey. We find that SFR does depend on environment, but only for intermediate-stellar mass galaxies (1010.1 < M */M⊙ < 1010.8) wherein the median SFR at the highest densities is 0.2–0.3 dex less than at lower densities at a significance of 4σ. Galaxies that are more/less massive than this have SFRs that vary at most by |${\approx }20{{\ \rm per\ cent}}$| across all environments, but show no statistically significant trend. We further split galaxies into low-redshift (⁠|$z$| ∼ 0.8) and high-redshift (⁠|$z$| ∼ 1.05) subsamples and observe nearly identical behaviour. We devise a simple toy model to explore possible star formation histories for galaxies evolving between these redshifts. The key assumption in this model is that star-forming galaxies in a given environment-stellar mass bin can be described as a superposition of two exponential time-scales (SFR ∝  e − t /τ): a long−τ time-scale with τ = 4 Gyr to simulate 'normal' star-forming galaxies, and a short-τ time-scale with free τ (between 0.3 ≤ τ/Gyr ≤ 2) to simulate galaxies on a quenching trajectory. In general, we find that galaxies residing in low/high environmental densities are more heavily weighted to the long-τ/short-τ pathways, respectively, which we argue is a signature of environmental quenching. Furthermore, for intermediate-stellar mass galaxies this transition begins at intermediate-density environments suggesting that environmental quenching is relevant in group-like haloes and/or cluster infall regions. [ABSTRACT FROM AUTHOR]