The galaxy-halo connection from a joint lensing, clustering and abundance analysis in the CFHTLenS/VIPERS field

We present new constraints on the relationship between galaxies and their host dark matter halos, measured from the location of the peak of the stellar-to-halo mass ratio (SHMR), up to the most massive galaxy clusters at redshift $z\sim0.8$ and over a volume of nearly 0.1~Gpc$^3$. We use a unique combination of deep observations in the CFHTLenS/VIPERS field from the near-UV to the near-IR, supplemented by $\sim60\,000$ secure spectroscopic redshifts, analysing galaxy clustering, galaxy-galaxy lensing and the stellar mass function. We interpret our measurements within the halo occupation distribution (HOD) framework, separating the contributions from central and satellite galaxies. We find that the SHMR for the central galaxies peaks at $M_{\rm h, peak} = 1.9^{+0.2}_{-0.1}\times10^{12} M_{\odot}$ with an amplitude of $0.025$, which decreases to $\sim0.001$ for massive halos ($M_{\rm h} > 10^{14} M_{\odot}$). Compared to central galaxies only, the total SHMR (including satellites) is boosted by a factor 10 in the high-mass regime (cluster-size halos), a result consistent with cluster analyses from the literature based on fully independent methods. After properly accounting for differences in modelling, we have compared our results with a large number of results from the literature up to $z=1$: we find good general agreement, independently of the method used, within the typical stellar-mass systematic errors at low to intermediate mass (${M}_{\star} < 10^{11} M_{\odot}$) and the statistical errors above. We have also compared our SHMR results to semi-analytic simulations and found that the SHMR is tilted compared to our measurements in such a way that they over- (under-) predict star formation efficiency in central (satellite) galaxies.Comment: 31 pages, 18 figures, 4 table. Accepted for publication in MNRAS. Online material available at http://www.cfhtlens.or

Multiwavelength scaling relations in galaxy groups: a detailed comparison of GAMA and KiDS observations to BAHAMAS simulations

We study the scaling relations between the baryonic content and total mass of groups of galaxies, as these systems provide a unique way to examine the role of non-gravitational processes in structure formation. Using Planck and ROSAT data, we conduct detailed comparisons of the stacked thermal Sunyaev-Zel’dovich (tSZ) and X-ray scaling relations of galaxy groups found in the Galaxy And Mass Assembly (GAMA) survey and the BAHAMAS hydrodynamical simulation. We use weak gravitational lensing data from the Kilo Degree Survey to determine the average halo mass of the studied systems. We analyse the simulation in the same way, using realistic weak lensing, X-ray, and tSZ synthetic observations. Furthermore, to keep selection biases under control, we employ exactly the same galaxy selection and group identification procedures to the observations and simulation. Applying this comparison, we find that the simulations reproduce the richness, size, and stellar mass functions of GAMA groups, as well as the stacked weak lensing and tSZ signals in bins of group stellar mass. However, the simulations predict X-ray luminosities that are higher than observed for this optically selected group sample. As the same simulations were previously shown to match the luminosities of X-ray-selected groups, this suggests that X-ray-selected systems may form a biased subset. Finally, we demonstrate that our observational processing of the X-ray and tSZ signals is free of significant biases. We find that our optical group selection procedure has, however, some room for improvement

KiDS-450: cosmological parameter constraints from tomographic weak gravitational lensing

We present cosmological parameter constraints from a tomographic weak gravitational lensing analysis of ∼450 deg2 of imaging data from the Kilo Degree Survey (KiDS). For a flat Λ cold dark matter (ΛCDM) cosmology with a prior on H0 that encompasses the most recent direct measurements, we find S8≡σ8Ωm/0.3−−−−−−√=0.745±0.039⁠. This result is in good agreement with other low-redshift probes of large-scale structure, including recent cosmic shear results, along with pre-Planck cosmic microwave background constraints. A 2.3σ tension in S8 and ‘substantial discordance’ in the full parameter space is found with respect to the Planck 2015 results. We use shear measurements for nearly 15 million galaxies, determined with a new improved ‘self-calibrating’ version of lensFIT validated using an extensive suite of image simulations. Four-band ugri photometric redshifts are calibrated directly with deep spectroscopic surveys. The redshift calibration is confirmed using two independent techniques based on angular cross-correlations and the properties of the photometric redshift probability distributions. Our covariance matrix is determined using an analytical approach, verified numerically with large mock galaxy catalogues. We account for uncertainties in the modelling of intrinsic galaxy alignments and the impact of baryon feedback on the shape of the non-linear matter power spectrum, in addition to the small residual uncertainties in the shear and redshift calibration. The cosmology analysis was performed blind. Our high-level data products, including shear correlation functions, covariance matrices, redshift distributions, and Monte Carlo Markov chains are available at http://kids.strw.leidenuniv.nl

The galaxy-halo connection from a joint lensing, clustering and abundance analysis in the CFHTLenS/VIPERS field

We present new constraints on the relationship between galaxies and their host dark matter haloes, measured from the location of the peak of the stellar-to-halo mass ratio (SHMR), up to the most massive galaxy clusters at redshift z∼0.8 and over a volume of nearly 0.1Gpc3. We use a unique combination of deep observations in the CFHTLenS/VIPERS field from the near-UV to the near-IR, supplemented by ∼60 000 secure spectroscopic redshifts, analysing galaxy clustering, galaxy-galaxy lensing and the stellar mass function. We interpret our measurements within the halo occupation distribution (HOD) framework, separating the contributions from central and satellite galaxies. We find that the SHMR for the central galaxies peaks at $M_{\rm h, peak} = 1.9^{+0.2}_{-0.1}\times 10^{12}{\,{\rm M}_{{\odot }}}$ with an amplitude of 0.025, which decreases to ∼0.001 for massive haloes (${{{M}_{\rm h}}}> 10^{14} {\,{\rm M}_{{\odot }}}$). Compared to central galaxies only, the total SHMR (including satellites) is boosted by a factor of 10 in the high-mass regime (cluster-size haloes), a result consistent with cluster analyses from the literature based on fully independent methods. After properly accounting for differences in modelling, we have compared our results with a large number of results from the literature up to z=1: we find good general agreement, independently of the method used, within the typical stellar-mass systematic errors at low to intermediate mass (${{{M}_{\rm \star }}}<10^{11} {\,{\rm M}_{{\odot }}}$) and the statistical errors above. We have also compared our SHMR results to semi-analytic simulations and found that the SHMR is tilted compared to our measurements in such a way that they over- (under-) predict star formation efficiency in central (satellite) galaxie

Gravitational lensing analysis of the Kilo-Degree Survey

The Kilo-Degree Survey (KiDS) is a multi-band imaging survey designed for cosmological studies from weak lensing and photometric redshifts. It uses the European Southern Observatory VLT Survey Telescope with its wide-field camera OmegaCAM. KiDS images are taken in four filters similar to the Sloan Digital Sky Survey ugri bands. The best seeing time is reserved for deep r-band observations. The median 5σ limiting AB magnitude is 24.9 and the median seeing is below 0.7 arcsec. Initial KiDS observations have concentrated on the Galaxy and Mass Assembly (GAMA) regions near the celestial equator, where extensive, highly complete redshift catalogues are available. A total of 109 survey tiles, 1 square degree each, form the basis of the first set of lensing analyses of halo properties of GAMA galaxies. Nine galaxies per square arcminute enter the lensing analysis, for an effective inverse shear variance of 69 arcmin−2. Accounting for the shape measurement weight, the median redshift of the sources is 0.53. KiDS data processing follows two parallel tracks, one optimized for weak lensing measurement and one for accurate matched-aperture photometry (for photometric redshifts). This technical paper describes the lensing and photometric redshift measurements (including a detailed description of the Gaussian aperture and photometry pipeline), summarizes the data quality and presents extensive tests for systematic errors that might affect the lensing analyses. We also provide first demonstrations of the suitability of the data for cosmological measurements, and describe our blinding procedure for preventing confirmation bias in the scientific analyses. The KiDS catalogues presented in this paper are released to the community through http://kids.strw.leidenuniv.nl

Dependence of GAMA galaxy halo masses on the cosmic web environment from 100 deg2 of KiDS weak lensing data

Galaxies and their dark matter haloes are part of a complex network of mass structures, collectively called the cosmic web. Using the tidal tensor prescription these structures can be classified into four cosmic environments: voids, sheets, filaments and knots. As the cosmic web may influence the formation and evolution of dark matter haloes and the galaxies they host, we aim to study the effect of these cosmic environments on the average mass of galactic haloes. To this end we measure the galaxy–galaxy lensing profile of 91 195 galaxies, within 0.039 < z < 0.263, from the spectroscopic Galaxy And Mass Assembly survey, using ∼100deg2∼100deg2 of overlapping data from the Kilo-Degree Survey. In each of the four cosmic environments we model the contributions from group centrals, satellites and neighbouring groups to the stacked galaxy–galaxy lensing profiles. After correcting the lens samples for differences in the stellar mass distribution, we find no dependence of the average halo mass of central galaxies on their cosmic environment. We do find a significant increase in the average contribution of neighbouring groups to the lensing profile in increasingly dense cosmic environments. We show, however, that the observed effect can be entirely attributed to the galaxy density at much smaller scales (within 4 h−1 Mpc), which is correlated with the density of the cosmic environments. Within our current uncertainties we find no direct dependence of galaxy halo mass on their cosmic environment

Quantitative in vivo receptor binding IV: Detection of muscarinic receptor down-regulation by equilibrium and by tracer kinetic methods

Newly-developed methods for estimation of in vivo binding to neurotransmitter receptors should enable the detection and quantification of physiologic or pathologic changes in receptor numbers. In the present study, both equilibrium and kinetic experimental strategies for in vivo muscarinic receptor determination were applied to the detection of receptor changes induced by chronic inhibition of acetylcholinesterase in the rat. Following one week of treatment, in vitro receptor autoradiography utilizing [ 3 H]scopolamine revealed significant losses of muscarinic binding in the cerebral cortex, hippocampus, striatum and in cranial nerve motor nuclei. The in vivo distribution of [ 3 H]scopolamine, following infusion to approach equilibrium binding in the brain, revealed reductions in binding which paralleled the pattern and magnitude of changes detected in vitro. A simplified tracer kinetic estimation following bolus injection of the ligand also detected substantial reductions in forebrain muscarinic receptor binding. These results indicate the feasibility of detecting receptor changes underlying neuropathologic conditions in vivo, and suggest that either equilibrium or kinetic experimental approaches may be extended to clinical research applications with the use of positron or single-photon emission tomography.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45405/1/11064_2004_Article_BF00965845.pd

Galaxy And Mass Assembly (GAMA): Gas Fuelling of Spiral Galaxies in the Local Universe II. – Direct Measurement of the Dependencies on Redshift and Host Halo Mass of Stellar Mass Growth in Central Disk Galaxies

We present a detailed analysis of the specific star formation rate – stellar mass (sSFR − M*) of z ≤ 0.13 disk central galaxies using a morphologically selected mass-complete sample (M* ≥ 109.5M⊙). Considering samples of grouped and ungrouped galaxies, we find the sSFR − M* relations of disk-dominated central galaxies to have no detectable dependence on host dark-matter halo (DMH) mass, even where weak-lensing measurements indicate a difference in halo mass of a factor ≳ 5. We further detect a gradual evolution of the sSFR − M* relation of non-grouped (field) central disk galaxies with redshift, even over a Δz ≈ 0.04 (≈5 · 108yr) interval, while the scatter remains constant. This evolution is consistent with extrapolation of the ”main-sequence-of-star-forming-galaxies” from previous literature that uses larger redshift baselines and coarser sampling. Taken together, our results present new constraints on the paradigm under which the SFR of galaxies is determined by a self-regulated balance between gas inflows and outflows, and consumption of gas by star-formation in disks, with the inflow being determined by the product of the cosmological accretion rate and a fuelling-efficiency – M ˙ b,halo ζ M˙b,haloζ . In particular, maintaining the paradigm requires M ˙ b,halo ζ M˙b,haloζ to be independent of the mass Mhalo of the host DMH. Furthermore, it requires the fuelling-efficiency ζ to have a strong redshift dependence (∝(1 + z)2.7 for M* = 1010.3M⊙ over z = 0 − 0.13), even though no morphological transformation to spheroids can be invoked to explain this in our disk-dominated sample. The physical mechanisms capable of giving rise to such dependencies of ζ on Mhalo and z for disks are unclea