We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ∼ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared ...observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed M
UV-M
* relation has a shallow slope more consistent with a constant mass-to-light ratio and a normalization which evolves with redshift. Our stellar mass functions have steep low-mass slopes (α ≈ −1.9), steeper than previously observed at these redshifts and closer to that of the UV luminosity function. Integrating our new mass functions, we find the observed stellar mass density evolves from
$\log _{10} \rho _{*} = 6.64^{+0.58}_{-0.89}$
at z ∼ 7 to 7.36 ± 0.06 M⊙ Mpc− 3 at z ∼ 4. Finally, combining the measured UV continuum slopes (β) with their rest-frame UV luminosities, we calculate dust-corrected star formation rates (SFR) for our sample. We find the specific SFR for a fixed stellar mass increases with redshift whilst the global SFR density falls rapidly over this period. Our new SFR density estimates are higher than previously observed at this redshift.
In this work, we present the first cosmology results from large-scale structure using the full 5000 deg2 of imaging data from the Dark Energy Survey (DES) Data Release 1. We perform an analysis of ...large-scale structure combining three two-point correlation functions ( 3×2pt ): (i) cosmic shear using 100 million source galaxies, (ii) galaxy clustering, and (iii) the cross-correlation of source galaxy shear with lens galaxy positions, galaxy–galaxy lensing. To achieve the cosmological precision enabled by these measurements has required updates to nearly every part of the analysis from DES Year 1, including the use of two independent galaxy clustering samples, modeling advances, and several novel improvements in the calibration of gravitational shear and photometric redshift inference. The analysis was performed under strict conditions to mitigate confirmation or observer bias; we describe specific changes made to the lens galaxy sample following unblinding of the results and tests of the robustness of our results to this decision. We model the data within the flat Λ CDM and wCDM cosmological models, marginalizing over 25 nuisance parameters. We find consistent cosmological results between the three two-point correlation functions; their combination yields clustering amplitude S8=0.776-0.017+0.017 and matter density Ω m =0.339-0.031+0.032 in Λ CDM , mean with 68% confidence limits; S8=0.775-0.024+0.026 , Ω m =0.352-0.041+0.035 , and dark energy equation-of-state parameter w=-0.98-0.20+0.32 in wCDM . These constraints correspond to an improvement in signal-to-noise of the DES Year 3 3×2pt data relative to DES Year 1 by a factor of 2.1, about 20% more than expected from the increase in observing area alone. This combination of DES data is consistent with the prediction of the model favored by the Planck 2018 cosmic microwave background (CMB) primary anisotropy data, which is quantified with a probability-to-exceed p=0.13 –0.48. We find better agreement between DES 3×2pt and Planck than in DES Y1, despite the significantly improved precision of both. When combining DES 3×2pt data with available baryon acoustic oscillation, redshift-space distortion, and type Ia supernovae data, we find p=0.34 . Combining all of these datasets with Planck CMB lensing yields joint parameter constraints of S8=0.812-0.008+0.008 , Ω m =0.306-0.005+0.004 , h=0.680-0.003+0.004 , and Σmν<0.13 eV (95% C.L.) in Λ CDM ; S8=0.812-0.008+0.008 , Ω m =0.302-0.006+0.006 , h=0.687-0.007+0.006 , and w=-1.031-0.027+0.030 in wCDM .
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 S8≡σ8 Ω m / 0.3 at the 3% level in Λ CDM : S8=0.759-0.023+0.025 (68% CL). Our constraint is at the 2% level when using angular scale cuts that are optimized for the Λ CDM analysis: S8=0.772-0.017+0.018 (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 S8 than the CMB-inferred value by 2.3σ (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 0.3σ in the plane of S8× Ω m caused by uncertainties in the theoretical models.
Abstract
We present a new constraint on the Hubble constant
H
0
using a sample of well-localized gravitational-wave (GW) events detected during the first three LIGO/Virgo observing runs as dark ...standard sirens. In the case of dark standard sirens, a unique host galaxy is not identified, and the redshift information comes from the distribution of potential host galaxies. From the third LIGO/Virgo observing run detections, we add the asymmetric-mass binary black hole GW190412 and the high-confidence GW candidates S191204r, S200129m, and S200311bg to the sample of dark standard sirens analyzed in Palmese et al. Our sample contains the top 20% (based on localization) GW events and candidates to date with significant coverage by the Dark Energy Spectroscopic Instrument Legacy Survey. We combine the
H
0
posterior for eight dark siren events, finding
H
0
=
79.8
−
12.8
+
19.1
km
s
−
1
Mpc
−
1
(68% highest density interval) for a prior in
H
0
uniform between 20, 140 km s
−1
Mpc
−1
. This result shows that a combination of eight well-localized dark sirens combined with an appropriate galaxy catalog is able to provide an
H
0
constraint that is competitive (∼20% versus 18% precision) with a single bright standard siren analysis (i.e., assuming the electromagnetic counterpart) using GW170817. When combining the posterior with that from GW170817, we obtain
H
0
=
72.77
−
7.55
+
11.0
km
s
−
1
Mpc
−
1
. This result is broadly consistent with recent
H
0
estimates from both the cosmic microwave background and supernovae.
We investigate galactic-scale outflows in the redshift range 0.71 ≤ z ≤ 1.63, using 413 K-band selected galaxies observed in the spectroscopic follow-up of the UKIDSS Ultra-Deep Survey (UDSz). The ...galaxies have an average stellar mass of ∼109.5 M and span a wide range in rest-frame colours, representing typical star-forming galaxies at this epoch. We stack the spectra by various galaxy properties, including stellar mass, O ii equivalent width, star formation rate, specific star formation rate and rest-frame spectral indices. We find that outflows are present in virtually all spectral stacks, with velocities ranging from 100 to 1000 km s−1, indicating that large-scale outflowing winds are a common property at these redshifts. The highest velocity outflows (>500 km s−1) are found in galaxies with the highest stellar masses and the youngest stellar populations. Our findings suggest that high-velocity galactic outflows are mostly driven by star-forming processes rather than active galactic nuclei, with implied mass outflow rates comparable to the rates of star formation. Such behaviour is consistent with models required to reproduce the high-redshift mass-metallicity relation.
We perform a joint analysis of the counts of redMaPPer clusters selected from the Dark Energy Survey (DES) year 1 data and multiwavelength follow-up data collected within the 2500 deg2 South Pole ...Telescope (SPT) Sunyaev-Zel'dovich (SZ) survey. The SPT follow-up data, calibrating the richness-mass relation of the optically selected redMaPPer catalog, enable the cosmological exploitation of the DES cluster abundance data. To explore possible systematics related to the modeling of projection effects, we consider two calibrations of the observational scatter on richness estimates: a simple Gaussian model which account only for the background contamination (BKG), and a model which further includes contamination and incompleteness due to projection effects (PRJ). Assuming either a Λ CDM + ∑ mν or w CDM + ∑ mν cosmology, and for both scatter models, we derive cosmological constraints consistent with multiple cosmological probes of the low and high redshift Universe, and in particular with the SPT cluster abundance data. This result demonstrates that the DES Y1 and SPT cluster counts provide consistent cosmological constraints, if the same mass calibration data set is adopted. It thus supports the conclusion of the DES Y1 cluster cosmology analysis which interprets the tension observed with other cosmological probes in terms of systematics affecting the stacked weak lensing analysis of optically selected low–richness clusters. Finally, we analyze the first combined optically SZ selected cluster catalog obtained by including the SPT sample above the maximum redshift probed by the DES Y1 redMaPPer sample (z = 0.65). Besides providing a mild improvement of the cosmological constraints, this data combination serves as a stricter test of our scatter models: the PRJ model, providing scaling relations consistent between the two abundance and multiwavelength follow-up data, is favored over the BKG model.
Two of the most sensitive probes of the large scale structure of the universe are the clustering of galaxies and the tangential shear of background galaxy shapes produced by those foreground ...galaxies, so-called galaxy-galaxy lensing. Combining the measurements of these two two-point functions leads to cosmological constraints that are independent of the galaxy bias factor. The optimal choice of foreground, or lens, galaxies is governed by the joint, but conflicting requirements to obtain accurate redshift information and large statistics. We present cosmological results from the full 5000 sq. deg2 of the Dark Energy Survey first three years of observations (Y3) combining those two-point functions, using for the first time a magnitude-limited lens sample (MagLim) of 11 million galaxies especially selected to optimize such combination, and 100 million background shapes. We consider two cosmological models, flat ΛCDM and wCDM. In ΛCDM we obtain for the matter density Ωm = 0.320$^{+0.041}_{–0.034}$ and for the clustering amplitude S8 = σ8(Ωm/0.3)0.5 = 0.778$^{+0.037}_{–0.031}$, at 68% C.L. The latter is only 1σ smaller than the prediction in this model informed by measurements of the cosmic microwave background by the Planck satellite. In wCDM we find Ωm = 0.32$^{+0.044}_{–0.046}$, S8 = 0.777$^{+0.049}_{–0.051}$, and dark energy equation of state w = –1.031$^{+0.218}_{–0.379}$. We find that including smaller scales while marginalizing over non-linear galaxy bias improves the constraining power in the Ωm – S8 plane by 31% and in the Ωm – w plane by 41% while yielding consistent cosmological parameters from those in the linear bias case. Furthermore, these results are combined with those from cosmic shear in a companion paper to present full DES-Y3 constraints from the three two-point functions (3 x 2pt).
We explore the redshift evolution of a curious correlation between the star formation properties of central galaxies and their satellites (‘galactic conformity’) at intermediate to high redshift (0.4 ...< z < 1.9). Using an extremely deep near-infrared survey, we study the distribution and properties of satellite galaxies with stellar masses, log(M
*/M⊙) > 9.7, around central galaxies at the characteristic Schechter function mass, M ∼ M*. We fit the radial profiles of satellite number densities with simple power laws, finding slopes in the range −1.1 to −1.4 for mass-selected satellites, and −1.3 to −1.6 for passive satellites. We confirm the tendency for passive satellites to be preferentially located around passive central galaxies at 3σ significance and show that it exists to at least z ∼ 2. Meanwhile, the quenched fraction of satellites around star-forming galaxies is consistent with field galaxies of equal stellar masses. We find no convincing evidence for a redshift-dependent evolution of these trends. One simple interpretation of these results is that only passive central galaxies occupy an environment that is capable of independently shutting off star formation in satellite galaxies. By examining the satellites of higher stellar mass star-forming galaxies (log(M
*/M⊙) > 11), we conclude that the origin of galactic conformity is unlikely to be exclusively due to the host dark matter halo mass. A halo-mass-independent correlation could be established by either formation bias or a more physical connection between central and satellite star formation histories. For the latter, we argue that a star formation (or active galactic nucleus) related outburst event from the central galaxy could establish a hot halo environment which is then capable of quenching both central and satellite galaxies.
We use the United Kingdom Infrared Telescope Deep Sky Survey (UKIDSS) Ultra Deep Survey (UDS), the deepest degree-scale near-infrared survey to date, to investigate the clustering of star-forming and ...passive galaxies to z ∼ 3.5. Our new measurements include the first determination of the clustering for passive galaxies at z > 2, which we achieve using a cross-correlation technique. We find that passive galaxies are the most strongly clustered, typically hosted by massive dark matter haloes with M
halo > 5 × 1012 M irrespective of redshift or stellar mass. Our findings are consistent with models in which a critical halo mass determines the transition from star-forming to passive galaxies. Star-forming galaxies show no strong correlation between stellar mass and halo mass, but passive galaxies show evidence for an anticorrelation; low-mass passive galaxies appear, on average, to be located in the most massive haloes. These results can be understood if the termination of star formation is most efficient for galaxies of low stellar mass in very dense environments.
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