Dark Energy Survey Year 3 results: Constraints on extensions to ΛcDM with weak lensing and galaxy clustering

We constrain six possible extensions to the Λ cold dark matter (CDM) model using measurements from the Dark Energy Survey's first three years of observations, alone and in combination with external cosmological probes. The DES data are the two-point correlation functions of weak gravitational lensing, galaxy clustering, and their cross-correlation. We use simulated data vectors and blind analyses of real data to validate the robustness of our results to astrophysical and modeling systematic errors. In many cases, constraining power is limited by the absence of theoretical predictions beyond the linear regime that are reliable at our required precision. The ΛCDM extensions are dark energy with a time-dependent equation of state, nonzero spatial curvature, additional relativistic degrees of freedom, sterile neutrinos with eV-scale mass, modifications of gravitational physics, and a binned σ8(z) model which serves as a phenomenological probe of structure growth. For the time-varying dark energy equation of state evaluated at the pivot redshift we find (wp,wa)=(-0.99-0.17+0.28,-0.9±1.2) at 68% confidence with zp=0.24 from the DES measurements alone, and (wp,wa)=(-1.03-0.03+0.04,-0.4-0.3+0.4) with zp=0.21 for the combination of all data considered. Curvature constraints of ωk=0.0009±0.0017 and effective relativistic species Neff=3.10-0.16+0.15 are dominated by external data, though adding DES information to external low-redshift probes tightens the ωk constraints that can be made without cosmic microwave background observables by 20%. For massive sterile neutrinos, DES combined with external data improves the upper bound on the mass meff by a factor of 3 compared to previous analyses, giving 95% limits of (ΔNeff,meff)≤(0.28,0.20 eV) when using priors matching a comparable Planck analysis. For modified gravity, we constrain changes to the lensing and Poisson equations controlled by functions ς(k,z)=ς0ωΛ(z)/ωΛ,0 and μ(k,z)=μ0ωΛ(z)/ωΛ,0, respectively, to ς0=0.6-0.5+0.4 from DES alone and (ς0,μ0)=(0.04±0.05,0.08-0.19+0.21) for the combination of all data, both at 68% confidence. Overall, we find no significant evidence for physics beyond ΛCDM

Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Modeling Uncertainty

This work and its companion paper, Amon et al. [Phys. Rev. D 105, 023514 (2022)], present cosmic shear measurements and cosmological constraints from over 100 million source galaxies in the Dark Energy Survey (DES) Year 3 data. We constrain the lensing amplitude parameter S 8 ≡ σ 8 √ Ω m / 0.3 at the 3% level in Λ CDM : S 8 = 0.75 9 + 0.025 − 0.023 (68% CL). Our constraint is at the 2% level when using angular scale cuts that are optimized for the Λ CDM analysis: S 8 = 0.77 2 + 0.018 − 0.017 (68% CL). With cosmic shear alone, we find no statistically significant constraint on the dark energy equation-of-state parameter at our present statistical power. We carry out our analysis blind, and compare our measurement with constraints from two other contemporary weak lensing experiments: the Kilo-Degree Survey (KiDS) and Hyper-Suprime Camera Subaru Strategic Program (HSC). We additionally quantify the agreement between our data and external constraints from the Cosmic Microwave Background (CMB). Our DES Y3 result under the assumption of Λ CDM is found to be in statistical agreement with Planck 2018, although favors a lower S 8 than the CMB-inferred value by 2.3 σ (a p -value of 0.02). This paper explores the robustness of these cosmic shear results to modeling of intrinsic alignments, the matter power spectrum and baryonic physics. We additionally explore the statistical preference of our data for intrinsic alignment models of different complexity. The fiducial cosmic shear model is tested using synthetic data, and we report no biases greater than 0.3 σ in the plane of S 8 × Ω m caused by uncertainties in the theoretical models

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Biossegurança em uma unidade de terapia intensiva: a percepção da equipe de enfermagem Bioseguridad en una unidad de terapia intensiva: la percepción del equipo de enfermería Biosecurity in an intensive care unit: the nursing team perception

O estudo, de cunho descritivo com abordagem qualitativa, teve como objetivos: descrever as medidas de biossegurança adotadas pela equipe de enfermagem durante a assistência prestada em UTI; identificar a percepção da equipe de enfermagem acerca da importância da adoção e implementação de medidas de biossegurança durante esta assistência e analisar as possibilidades de implementação por esta equipe de medidas de biossegurança durante esta assistência. Os dados foram obtidos por meio de observação sistemática e entrevistas com roteiro semi-estruturado, realizadas na UTI onde trabalhavam 29 profissionais de enfermagem.A análise temática das entrevistas permitiu identificar três categorias: medidas de biossegurança adotadas pela equipe de enfermagem; percepção desta equipe em relação à importância da adoção e implementação das medidas de biossegurança; e possibilidades de intervenção para a adoção e implementação de medidas de biossegurança.Verificou-se que as normas de biossegurança devem incluir as "boas práticas", possibilitando alcançar um ambiente laboral sem riscos ocupacionais.<br>El estudio es de cuño descriptivo con abordaje cualitativo, tuvo como objetivos: describir las medidas de bioseguridad adoptadas por el equipo de enfermería durante la asistencia prestada en UTI; identificar la percepción del equipo de enfermería acerca de la importancia de la adopción e implementación de medidas de bioseguridad durante esta asistencia y analizar las posibilidades de implementación por este equipo de medidas de bioseguridad durante esta asistencia. Los datos se han obtenido por medio de observación sistemática y entrevistas con guión semi-estructurado, realizadas en la UTI donde trabajaban 29 profesionales de enfermería. El análisis temático de las entrevistas permitió identificar tres categorías: medidas de bioseguridad adoptadas por el equipo de enfermería; la percepción de este equipo en relación con la importancia de adoptar e implementar las medidas de bioseguridad y posibilidades de intervención para la adopción e implementación de medidas de bioseguridad. Se ha verificado que las normas de bioseguridad deben incluir las buenas prácticas, posibilitando alcanzar un ambiente laboral sin riesgos ocupacionales.<br>The descriptive study having a qualitative approach aimed at: describing the biosecurity measures adopted by the nursing team during the attendance on an ICU identifying the perception of the nursing team about the importance of adopting and implementing biosecurity measures during the attendance and analyzing the possibilities to the team of implementing some biosecurity measures during the attendance. The data were obtained by means of the systematic observation and interviews with semi-structured script, carried out on an ICU where 29 nurses used to work. The thematic analysis of the interviews allowed identifying three categories: biosecurity measures adopted by the nurse team; perception of this team concerning the importance of adopting and implementing the biosecurity measures and the possibilities of intervention for the adoption and implementation of the biosecurity measures. It was verified that the biosecurity rules must include the good practices, making possible to reach a labor ambience with no occupational risks