To properly quantify possible residual systematic errors affecting the Classical Cepheid distance scale, a detailed theoretical scenario is recommended. By extending set of nonlinear convective pulsation models published for $Z=0.02$ \citep[][]{Desomma2020a} to $Z=0.004$, $Z=0.008$ and $Z=0.03$, we provide homogeneous model grid taking into account simultaneous variations mass-luminosity relati...

Different determinations currently suggest scattered values for the power spectrum normalization on the scale of galaxy clusters, σ8. Here we concentrate on the constraints coming from the X-ray temperature and luminosity functions (XTF and XLF), and investigate several possible sources of discrepancies in the results. Importantly, we have used two largely independent codes for the temperature ...

We present a detection of the Sunyaev–Zel’dovich (SZ) decrement associated with the luminous red galaxy (LRG) sample of the Sloan Digital Sky Survey. The SZ data come from 148 GHz maps of the equatorial region made by the Atacama Cosmology Telescope. The LRG sample is divided by luminosity into four bins, and estimates for the central SZ temperature decrement are calculated through a stacking p...

We develop an improved mass tracer for clusters of galaxies from optically observed parameters, and calibrate the mass relation using weak gravitational lensing measurements. We employ a sample of ∼13 000 optically selected clusters from the Sloan Digital Sky Survey (SDSS) maxBCG catalogue, with photometric redshifts in the range 0.1–0.3. The optical tracers we consider are cluster richness, cl...

We measure the distribution of velocity dispersions of groups of galaxies identified in the UZC catalog; we use the distribution to derive the group mass function. We introduce a new method which makes efficient use of the entire magnitude limited catalog. Our determination of n(≥ σT ) includes a significant contribution from low luminosity systems that would be missing in a volume limited samp...