The distribution of stellar mass in galaxy clusters over cosmic time

Understanding how galaxies form in our dark matter dominated Universe is a key goal of extragalactic astronomy. Both the stellar mass function and the spatial distribution of galaxies provide insights in the connection between dark matter and the stellar component. This thesis presents measurements on the stellar component in the most massive structures formed in the Universe, with the potential to test and further expand current physical models and thus our understanding of the cosmos. After studying 10 clusters in the distant Universe (Chapter 2-4), and 10 clusters in the local Universe (Chapter 5), we consider different evolutionary scenarios to explain the observed trends. Chapter 6 presents measurements on the very distant Universe, probing a time at which these massive structures have not yet formed.Sterrewacht Leiden NWO grant number 639.042.814 Leids Kerkhoven-Bosscha FondsUBL - phd migration 201

Towards Understanding The Origin And Evolution Of Ultra-Diffuse Galaxies

Article in monograph or in proceedingsSterrewach

Evidence for strong evolution in galaxy environmental quenching efficiency between z = 1.6 and z = 0.9

Indexación: Web of Science; Scopus.We analyse the evolution of environmental quenching efficiency, the fraction of quenched cluster galaxies which would be star forming if they were in the field, as a function of redshift in 14 spectroscopically confirmed galaxy clusters with 0.87 < z < 1.63 from the Spitzer Adaptation of the Red-Sequence Cluster Survey. The clusters are the richest in the survey at each redshift. Passive fractions rise from 42-13 +10 per cent at z ~ 1.6 to 80-9 +12 per cent at z ~ 1.3 and 88-3 +4 per cent at z < 1.1, outpacing the change in passive fraction in the field. Environmental quenching efficiency rises dramatically from 16-19 +15 per cent at z ~ 1.6 to 62-15 +21 per cent at z~1.3 and 73-7 +8 per cent at z ≲ 1.1. This work is the first to show direct observational evidence for a rapid increase in the strength of environmental quenching in galaxy clusters at z ~ 1.5, where simulations show cluster-mass haloes undergo non-linear collapse and virialization.https://academic.oup.com/mnrasl/article/465/1/L104/241728

A first constraint on the average mass of ultra-diffuse galaxies from weak gravitational lensing

Large scale structure and cosmolog

The galaxy-subhalo connection in low-redshift galaxy clusters from weak gravitational lensing

Large scale structure and cosmolog

CCCP and MENeaCS: (updated) weak-lensing masses for 100 galaxy clusters

Large scale structure and cosmolog

Gemini Observations of Galaxies in Rich Early Environments (GOGREEN) I: survey description

We describe a new Large Program in progress on the Gemini North and South telescopes: Gemini Observations of Galaxies in Rich Early Environments (GOGREEN). This is an imaging and deep spectroscopic survey of 21 galaxy systems at 1 10 in halo mass. The scientific objectives include measuring the role of environment in the evolution of low-mass galaxies, and measuring the dynamics and stellar contents of their host haloes. The targets are selected from the SpARCS, SPT, COSMOS, and SXDS surveys, to be the evolutionary counterparts of today's clusters and groups. The new red-sensitive Hamamatsu detectors on GMOS, coupled with the nod-and-shuffle sky subtraction, allow simultaneous wavelength coverage over λ ∼ 0.6–1.05 μm, and this enables a homogeneous and statistically complete redshift survey of galaxies of all types. The spectroscopic sample targets galaxies with AB magnitudes z΄ < 24.25 and [3.6] μm < 22.5, and is therefore statistically complete for stellar masses M* ≳ 1010.3 M⊙, for all galaxy types and over the entire redshift range. Deep, multiwavelength imaging has been acquired over larger fields for most systems, spanning u through K, in addition to deep IRAC imaging at 3.6 μm. The spectroscopy is ∼50 per cent complete as of semester 17A, and we anticipate a final sample of ∼500 new cluster members. Combined with existing spectroscopy on the brighter galaxies from GCLASS, SPT, and other sources, GOGREEN will be a large legacy cluster and field galaxy sample at this redshift that spectroscopically covers a wide range in stellar mass, halo mass, and clustercentric radius

Resolving galaxy cluster gas properties at z ~ 1 with XMM-Newton and Chandra

International audienceMassive, high-redshift, galaxy clusters are useful laboratories to test cosmological models and to probe structure formation and evolution, but observations are challenging due to cosmological dimming and angular distance effects. Here we present a pilot X-ray study of the five most massive (M500 > 5 × 1014M⊙), distant (z ~ 1), clusters detected via the Sunyaev-Zel’Dovich effect. We optimally combine XMM-Newton and Chandra X-ray observations by leveraging the throughput of XMM-Newton to obtain spatially-resolved spectroscopy, and the spatial resolution of Chandra to probe the bright inner parts and to detect embedded point sources. Capitalising on the excellent agreement in flux-related measurements, we present a new method to derive the density profiles, which are constrained in the centre by Chandra and in the outskirts by XMM-Newton. We show that the Chandra-XMM-Newton combination is fundamental for morphological analysis at these redshifts, the Chandra resolution being required to remove point source contamination, and the XMM-Newton sensitivity allowing higher significance detection of faint substructures. Measuring the morphology using images from both instruments, we found that the sample is dominated by dynamically disturbed objects. We use the combined Chandra-XMM-Newton density profiles and spatially-resolved temperature profiles to investigate thermodynamic quantities including entropy and pressure. From comparison of the scaled profiles with the local REXCESS sample, we find no significant departure from standard self-similar evolution, within the dispersion, at any radius, except for the entropy beyond 0.7 R500. The baryon mass fraction tends towards the cosmic value, with a weaker dependence on mass than that observed in the local Universe. We make a comparison with the predictions from numerical simulations. The present pilot study demonstrates the utility and feasibility of spatially-resolved analysis of individual objects at high-redshift through the combination of XMM-Newton and Chandra observations. Observations of a larger sample will allow a fuller statistical analysis to be undertaken, in particular of the intrinsic scatter in the structural and scaling properties of the cluster population.Key words: methods: data analysis / X-rays: galaxies: clusters / galaxies: clusters: intracluster mediu

Gradually varied open-channel flow profiles normalized by critical depth and analytically solved by using Gaussian hypergeometric functions

The equation of one-dimensional gradually varied flow (GVF) in sustaining and non-sustaining open channels is normalized using the critical depth, <i>y</i>_c, and then analytically solved by the direct integration method with the use of the Gaussian hypergeometric function (GHF). The GHF-based solution so obtained from the <i>y</i>_c-based dimensionless GVF equation is more useful and versatile than its counterpart from the GVF equation normalized by the normal depth, <i>y</i>_n, because the GHF-based solutions of the <i>y</i>_c-based dimensionless GVF equation for the mild (M) and adverse (A) profiles can asymptotically reduce to the <i>y</i>_c-based dimensionless horizontal (H) profiles as <i>y</i>_c/<i>y</i>_n &rarr; 0. An in-depth analysis of the <i>y</i>_c-based dimensionless profiles expressed in terms of the GHF for GVF in sustaining and adverse wide channels has been conducted to discuss the effects of <i>y</i>_c/<i>y</i>_n and the hydraulic exponent <i>N</i> on the profiles. This paper has laid the foundation to compute at one sweep the <i>y</i>_c-based dimensionless GVF profiles in a series of sustaining and adverse channels, which have horizontal slopes sandwiched in between them, by using the GHF-based solutions

Weak lensing magnification of SpARCS galaxy clusters

International audienceContext. Measuring and calibrating relations between cluster observables is critical for resource-limited studies. The mass–richness relation of clusters offers an observationally inexpensive way of estimating masses. Its calibration is essential for cluster and cosmological studies, especially for high-redshift clusters. Weak gravitational lensing magnification is a promising and complementary method to shear studies, that can be applied at higher redshifts.Aims. We aim to employ the weak lensing magnification method to calibrate the mass–richness relation up to a redshift of 1.4. We used the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS) galaxy cluster candidates (0.2 1.0 is 4.1σ; for the entire cluster sample we obtained an average M200 of 1.28 -0.21+0.23 × 1014 M⊙. Conclusions. Our measurements demonstrated the feasibility of using weak lensing magnification as a viable tool for determining the average halo masses for samples of high redshift galaxy clusters. The results also established the success of using galaxy over-densities to select massive clusters at z > 1. Additional studies are necessary for further modelling of the various systematic effects we discussed.Key words: gravitational lensing: weak / galaxies: clusters: general / galaxies: clusters: individual: SpARC