Anisotropic quenching is detected at the highest redshift yet and linked to preprocessing dominating over intrahalo effects by ~20% along the major axis in a delay-then-rapid quenching model informed by cluster accretion histories.
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COLOSSUS: A python toolkit for cosmology, large-scale structure, and dark matter halos
15 Pith papers cite this work. Polarity classification is still indexing.
abstract
This paper introduces Colossus, a public, open-source python package for calculations related to cosmology, the large-scale structure (LSS) of matter in the universe, and the properties of dark matter halos. The code is designed to be fast and easy to use, with a coherent, well-documented user interface. The cosmology module implements Friedman-Lemaitre-Robertson-Walker cosmologies including curvature, relativistic species, and different dark energy equations of state, and provides fast computations of the linear matter power spectrum, variance, and correlation function. The LSS module is concerned with the properties of peaks in Gaussian random fields and halos in a statistical sense, including their peak height, peak curvature, halo bias, and mass function. The halo module deals with spherical overdensity radii and masses, density profiles, concentration, and the splashback radius. To facilitate the rapid exploration of these quantities, Colossus implements more than 40 different fitting functions from the literature. I discuss the core routines in detail, with particular emphasis on their accuracy. Colossus is available at bitbucket.org/bdiemer/colossus.
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First near-IR weak-lensing analysis of CANDELS fields detects 12 shear-selected overdensities with masses 0.2-2.2 x 10^14 solar masses at redshifts 0.22-0.9 and mean z=0.68.
In 37 massive ETGs, the IMF becomes less bottom-heavy with radius, with average α_IMF falling from 2.16 to 1.74 and IMF gradients dominating M/L variations over stellar population effects.
JWST lensing data on 28 systems constrain dark matter free-streaming length to below 6-7 kpc and thermal relic mass above 6.5-7.4 keV, consistent with cold dark matter predictions.
Corrected empirical limits show the most massive galaxies never exceed the theoretical baryonic maximum of 0.16 times halo virial mass, keeping observations consistent with LambdaCDM at all redshifts.
A new multi-scale hierarchical framework in GR uses matter horizons to extend perturbation theory beyond shell-crossing by gluing spacetimes with opposite orientation.
Angular auto-correlation of gravitational wave sources decreases with lensing dispersion, and joint cross-correlation with galaxies partially breaks the degeneracy with source bias.
Five LRDs at z≈2 yield number density ≈7×10^{-6} cMpc^{-3}, confirming a decline from the z≈5 peak but gentler than prior photometric estimates.
New hydrodynamical simulations show that dwarf galaxy stellar mass-halo mass relations and star formation histories are more influenced by host halo concentration than by the 5 cMpc scale environment.
New UNIONS galaxy-galaxy lensing data around CMASS galaxies indicates no significant lensing is low problem, with joint HOD fits to GGL and GC favoring a slightly lower matter power spectrum amplitude than Planck.
Weak-lensing calibration of 19 Planck SZ clusters with HSC Year 3 yields 1-b = 0.73^{+0.10}_{-0.11} at z_eff ~0.24 after forward-modeling selection, Eddington bias, and miscentering.
Upper bounds on the dark matter fraction in MACHOs of 10^3 to 10^7 solar masses are derived from limits on distortions to the global 21-cm signal at z~17, z~89, and z>300.
50 constrained simulations of Coma cluster analogues reproduce the observed radial X-ray surface brightness and Compton-y profiles within the scatter expected from environment and assembly history.
An updated linear halo bias fit calibrated on high-redshift simulations reduces systematic offsets in early-universe clustering predictions to under 1%.
SKAO continuum surveys will detect radio emission from JWST AGN and LRDs and distinguish between Compton-thick absorption, intrinsically weak accretion, and dense gas cocoon scenarios.
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Constraining the lensing dispersion from the angular clustering of binary black hole mergers
Angular auto-correlation of gravitational wave sources decreases with lensing dispersion, and joint cross-correlation with galaxies partially breaks the degeneracy with source bias.